Advanced Daylight Technologies For Sustainable ...

ALEXANDRIA UNIVERSITY FACULTY OF ENGINEERING

Advanced Daylight Technologies For Sustainable Architectural Design

A Thesis Presented to the Department of Architecture Faculty of Engineering, Alexandria University In Partial Fulfillment of the Requirements for the degree of

Master of Science in

Architecture

By: Osama Mohamed El-said Omar B.Sc. Architecture, Alexandria University

Supervisors: Prof. Dr Samir Bayoumy Professor of Architecture, Department of Architecture Faculty of Engineering, Alexandria University And

Prof. Dr. Mohamed Anwar Fikry Professor of Architecture, Department of Architecture Faculty of Engineering, Alexandria University

Registered: September 2004 Submitted: July 2008


Presented by: Osama Mohamed El-said Omar B.Sc. Architecture, Alexandria University

For the degree of Master of Science In Architecture

Advisors' Committee: Prof. Dr. Samir Bayoumy Professor of Architecture, Department of Architecture, Faculty of Engineering, Alexandria University.

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Prof. Dr. Mohamed Anwar Fikry Professor of Architecture, Department of Architecture, Faculty of Engineering, Alexandria University.

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Presented by: Osama Mohamed El-said Omar B.Sc. Architecture, Alexandria University

For the degree of Master of Science In Architecture

Examiner's Committee:

Approved

Prof. Dr. Mohamed Abd El- Al Ibrahim Professor of Architecture, Department of Architecture Faculty of Engineering, Alexandria University

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Prof. Dr. Magdy Moussa Professor of Architecture, Department of Architecture Faculty of Fine Arts, Alexandria University

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Prof. Dr. Samir H.B. Hosni Professor of Architecture, Department of Architecture Faculty of Engineering, Alexandria University

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For the council of the Faculty of Engineering Prof. Dr. Ebthal Bastawese. Vice Dean for High Studies and Research Faculty of Engineering, Alexandria University

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Preface For many years, daylight was the only efficient source of light available. Architecture was dominated by the goal of spanning wide spaces and creating openings large enough to distribute daylight to building interiors. Efficient artificial light sources and fully glazed facades have liberated designers from these constraints of the past. Advanced daylighting systems and control strategies are another step forward in providing day lit, user-friendly, energy-efficient building environments. These systems need to be integrated in to a building’s overall architectural strategy and incorporated into the design process from its earliest stages. Quality and quantity of light inside building are important factors that intensively influence occupants’ productivity and physiological performance. As a result, architects should insure adequate internal luminous environment by implementing either artificial light source or natural daylight. Daylighting strategies and architectural design strategies are inseparable. Daylight not only replaces artificial lighting, reducing lighting energy use, but also influences both heating and cooling load. Planning for daylight therefore involves integrating the perspectives and requirements of various specialties and professionals. Daylighting design starts with the selection of a building site and continues as long as the building is occupied [Fontoynont 1999]. In modern society, architects, building engineers are called upon to create high-quality indoor environments which provide thermal, aural and visual comfort in order to maintain the productivity of space users. These same architects, engineers and managers are also increasingly asked to consider the sustainability of raw materials, energy and natural resources. However, many remain wholly influenced by the performance of buildings in operation, using components which are less sustainable but permit greater control over the indoor environment and the comfort of its occupants. It is not often considered that both these criteria can be met by appropriate building component Selection. Proponents of sustainable design have argued that environmentally friendly technologies and design strategies enhance environmental quality by such features as increased use of Daylighting and increased contact with the natural environment. However, commonly used features such as open plan spaces can make it more difficult to create productive working conditions by increasing noise levels, making thermal comfort harder to achieve and reducing access to daylight in large, deep space [G.F. Menzies, J.R.Wherrett, 2003] This thesis mainly considers sustainable daylight, simulation program for daylighting, but it is also an overview of advanced daylight technologies and daylighting calculation. Hopefully this thesis will give the reader some knowledge about this issue [The Researcher].

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Abstract Daylighting has been a part of built form throughout architectural history. Interest in using daylighting as a major design element has varied with the social and economic forces of the time. Since 1973, interest in daylighting has increased as a result of oil embargo and the understanding that electric lighting represents a major energy consumer. Energy savings achieved through the use of daylight also translate into energy cost savings from reduced electricity consumption for lighting and cooling as well as from reduced needs during peak demand periods in many building [ Fikry,2000]. The objective of this paper is to explain the great importance for daylighting and the role played in design process for the building and the participation in the design from the first step which effects the designer decision for dimensions, position for the opening and the building orientation, etc... Which give the psychological comfort for building user and how to control the heat transfer throw opening by using different materials and using simulation programs which give to the designer a clear image for what will be a situation all the year around? [The Researcher]. This research consists of an introduction, abstract in both Arabic and English. In addition to four detailed chapters as follows:

First Chapter: An introduction show the architect historical background to deal with the daylight. Also addressing the problem faces the architect in choosing the openings sizes that met daylight requirements in the space according to its uses. Then it is followed be the research objective which is achieving the design standards of the openings to achieve the sustainability objectives in the warm atmospheres using the modern techniques by using reliable renewable resources like daylighting, the study field and boundaries which is analytical and theoretical study of the daylight and experimental study through using the simulations programs. Research methodology consists of the theoretical and experimental approach. Eventually it shows the study results and recommendations [The Researcher].

Second Chapter: It contains the most important definitions such as sustainability as the maintaining the present and existing recourses and wealth for the next generations and replace it with the renewable resources like solar and wind energy, the natural delighting as the sun lighting or daylighting, and its effect on the design process. Also this chapter includes the architect historical background of dealing with the daylight as well as its value, importance, the benefits provided by visual, the psychological comfort which is helpful to increase the user productivity and his passions of designing the space to achieve psychological comfort. At the end of this chapter, showing the advanced techniques used in the daylight during five years (2000-2005). These techniques are still used until now with continuous developments during the last short period. Also stating different techniques used in various buildings and helped to achieve the highest rates of daylight inside these buildings [The Researcher].

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Third Chapter: This chapter consists of two main parts. Part one shows the calculation methods of daylight in the space which are “the calculation methods, flow charts, & simulation techniques”. Calculation methods include the spreadsheets, formulas, solving and doing a lot of long and difficult formulas which require high concentrations to avoid errors which give wrong picture of the situation in the space. While the flow charts comprise of the counter maps of the daylight rates in the space which give clear picture of the place needing more lighting. The third method is the simulation technique which enables the designer to use the simulation programs designed to help to imagine the situation in the space throughout the year. These programs are approved and certified by the Canadian supreme daylighting authority. The third method is the best way because of the high level of accuracy, speed, & comprehensive output. “Counter maps, flow charts values, mathematical rates, solar tracks throughout the year in the space, lighting forms in the space in different seasons. This information have been mentioned in the comparison table in the first part of this chapter while the second part present local examples (art museum of Ramses Wissa Wassef, 1970, Giza) and different European examples show the use of daylight in the early stages of the design process which is helpful to increase the building efficiency and effectiveness [The Researcher].

Fourth Chapter: This chapter shows the practical examples using one of the simulation program (Ecotech) which is approved by Canadian supreme daylighting authority. The 2nd year room in the architecture department, Engineering Faculty, Alexandria University is our case study because of low daylight rates problem in the space although the many windows on both sides of the room but the caused glare from the opened windows leads the students to close these windows and use the electric lighting in the morning. Simulation program show the counter maps of the room throughout the year and in different atmospheres. The program emphasized on the weak points of the room central area which causing problems to students because of its low daylight rates and reduce the optimal use of this room. The program helped to imagine the daylight forms in the space and sun tracks throughout the year. Accordingly, this chapter presents two new methods of daylight from the ceiling to increase the daylight rates in the room central area which is called the vertical lighting. The results and recommendations show the importance of using the daylight in the early stages of the design process and the use of the simulation program in calculating the daylight rates in the space to help the designer to assess the openings dimensions, places, as well as building direction to increase the daylight rates. The main objective of these programs is to rely on the renewable resources which are the main objective of the sustainability leading us to the designing standards helping the designer in the decision making of the initial design process [The Researcher].

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Acknowledgment I am most grateful to Prof. Samir Bayoumy for all what he did for me when I was an undergraduate student till this moment. I hope to thank my dear Prof. Mohamed Anwar Fikry for his continuous support and encouragement. I would like to express my sincere appreciation and gratitude to Prof. Tarek farghale for his support. Thanks to Dr. Christophe. Reinhart from National Research Council Canada who helped me to understand how Ecotect program work and for his support. I hope to thanks all my family and my friends...

Osama Mohamed El-said

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TABLE OF CONTENTS Preface… Abstract… Acknowledgement… Table of contents… List of figures… List of tables… Chapter One: 1-1 Introduction. 1-1-1 1-1-2 1-1-3 1-1-4 1-1-5

Background. Problem definition & importance of research. Objective. Methodology. Research outlines.

Chapter Two: 2-1 Definitions 2-1-1 Sustainability. 2-1-2 Daylight.

2-2 Why daylight? 2-2-1 What is light? 2-2-2 History of lighting. 2-2-3 Value of daylight. 2-2-4 Benefits of natural lighting.

2-3 Advanced Daylighting for sustainable architecture. 2-3-1 Classification of daylight elements. 2-3-2 Advanced technology and those developed in the last decade. 2-3-3 Recent innovative developments in the past 5 years(2000-2005). 2-3-4 Conclusion.

Chapter Three: 3-1 Daylighting Calculation. 3-1-1 Daylight prediction techniques. 3-1-1-1 Calculation methods. 3-1-1-2 Graphical methods. 3-1-1-3 Simulation methods. 3-1-2 Conclusion.

3-2 Determination of the ways to deal with daylight . 3-2-1 Showing the problem and its causes. 3-2-2 Example in Egypt. 3-2-3 Examples from Europe.

Chapter Four: 4-1 The application. 4-2 Final conclusions. References ….

I II IV V VI IX 1 2 2 2 3 3 3 7 8 8 12 16 16 16 17 18 21 21 22 35 51 52 53 53 58 60 61 66 67 67 67 69 84 85 95 97

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List of Figures Fig 1.1: The research outline diagram. Fig 1.2: Methodology diagram. Fig 2.1: Typical liner building design process used by many architectural firms. Fig 2.2: Steps in the redesign analysis phase of the building design process for using daylight in a building. Fig 2.3: Energy use and costs in a typical office building. Fig 2.4: Yasuda Academia building,Tokyo,Japan( Daylighting is achieved via solar glazing solar glazing / blind / louvers ). Fig 2.5: The Scottish office building,Edinburgh,UK( Daylighting is achieved via triple glazing window with integral louver). Fig 2.6: Shows a shading technique, PFIZER building 500, UK as green building (courtesy of FOCCHI,UK). Fig 2.7: Shows examples of automated blinds / louvers. Fig 2.8: Illustrates daylighting elements as solar shading panels. Fig 2.9: The optical sunscreen, Institute De Monde Arab, Paris France. Fig 2.10: Shows how HOE performs to direct light. Fig 2.11: Shows how External light Shelves are used to improve daylighting by reflection. Fig 2.12: Shows external and internal views of light shelves to improve daylighting condition. Fig 2.13: Shows different types of light shelves set up at both clear and overcast sky condition. Fig 2.14: Angular selective skylights on a building at Waterford state school Brisbane Australia. Fig 2.15: Rejection of high elevation light admission of law elevation light by an angular selective skylight. Fig 2.16: Angular selective skylights / sky dome as daylighting elements. Fig 2.17: Horizontal and ceiling Anidolic duct. Fig 2.18: A view of an Anidolic ceiling incorporated in to a courtyard to improve daylighting. Fig 2.19: Shows Zenitthal Light-guiding glass. Fig 2.20: The British Airway terminal using the Laser-cut panel, London, UK. Fig 2.21: The laser-cut panel installed in school classroom in Australia. Fig 2.22: Prismatic panels to control sunlight. Fig 2.23: Prismatic panels to control sunlight. Fig 2.24: Shows daylighting by using light pipes. Fig 2.25: Zenithal light pipe (sky dome) with movable reflectors. Fig 2.26: Daylighting via Electro chromic glazing. Fig 2.27: Light-redirecting skylight, Berlin. Fig 2.28: Oracular between-pane louver system. Fig 2.29: Solar Filters. Fig 2.30: A dual light shelf design, front Collins office building. Fig 2.31: Exterior Reflectors. Fig 2.32: Anidolic Mirrors. Fig 2.33: Prism panels.

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Fig 2.34: Shows recent innovative louvers. Fig 2.35: Shows recent innovative louvers. Fig 2.36: Shows recent innovative louvers. Fig 2.37: light pipes with step index fiber. Fig 2.38: The BRE Building. Fig 2.39: Cross section through the glazed faced (left) and the ventilation stack (right). Fig 2.40: Cross section through the glazed faced (left) and the ventilation stack (right). Fig 2.41: Cross section through the glazed faced (left) and the ventilation stack (right). Fig 2.42: Cross section through the glazed faced (left) and the ventilation stack (right). Fig 2.43: Cross section through the glazed faced (left) and the ventilation stack (right). Fig 2.44: Exterior views of the vertical louvers on the west faced. Fig 2.45: Exterior views of the vertical louvers on the west faced. Fig 2.46: Daylighting Inland Revenue Center in Nottingham, UK. Fig 2.47: Daylighting system in Center for Clinical Science Research. Fig 2.48: The Prismatic Panel reflects light to the desired angle. Fig 2.49: Double-skin faced made of external skin which consists of 15 mm laminated solar control glazing, the internal skin consists of solar control fixed glazing. Fig 2.50: HUK Coburg Office entry hall, Coburg, Germany. Fig 3.1: Diagram of daylight calculation classification. Fig 3.2: Example of daylight factor contours on horizontal working plan. Fig 3.3: BRE SC protractor number 2 for a vertical glazing under the CIE overcast sky. Fig 3.4: Simplified Waldram diagram for glazed apertures under the CIE overcast sky. Fig 3.5: Ecotect Interface. Fig 3.6: Daysim Interface. Fig 3.7: Radiance Interface. Fig 3.8: Master plan. Fig 3.9: Elevation & section diagram. Fig 3.10: Interior picture explain how used daylight to focus on the element. Fig 3.11: Interior picture for main hall. Fig 3.12: Master plans&Elevations. Fig 3.13 Sun movement and overcast sky dome behavior. Fig 3.14 The daylight zone. Fig 3.15 Elements of the design. Fig 3.16 Section of the building. Fig 3.17 Daylight Component. Fig 3.18 Case study. Fig 3.19 Windows Details. Fig 3.20 Daylight Window. Fig 3.21 Windows Details.

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Fig 3.22 Interior lightshelf. Fig 3.23 Common Material Selections. Fig 3.24 Analyses picture for the building. Fig 3.25 Roof plan. Fig 3.26 Modeling for building. Fig 3.27 Sun movement and overcast sky dome behavior. Fig 3.28 Simulation Equipments. Fig 3.29 Overcast sky simulation. Fig 3.30 Direct sun control. Fig 3.31 Upper level entry. Fig 3.32 Upper level entry. Fig 3.33 Lower level Dining / Cafe. Fig 3.34 Lower level Dining / Cafe. Fig 3.35 Gallery / Display space. Fig 3.36 Open office Area. Fig 3.37 Open office Area ( Overcast simulation ). Fig 4.1 Plan For Fourth Floor in Administration Building. Fig 4.2 Classroom plan. Fig 4.3 Picture For Classroom. Fig 4.4 Contours plan for classroom by Ecotect. Fig 4.5 Daylight Analysis for classroom in September. Fig 4.6 Contours plan for classroom in September. Fig 4.7 Sun path for classroom in September. Fig 4.8 Daylight Analysis for classroom in December. Fig 4.9 Contours plan for classroom in December. Fig 4.10 Sun path for classroom in December. Fig 4.11 Daylight Analysis for classroom in March. Fig 4.12 Contours plan for classroom in March. Fig 4.13 Sun path for classroom in March. Fig 4.14 Daylight Analysis for classroom in June. Fig 4.15 Contours plan for classroom in June. Fig 4.16 Sun path for classroom in June.

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Fig 4.17 Horizontal light pipe technology (HLP).

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Fig 4.18 Vertical light pipes technology (VLPs) with and without reflectors.

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List of Tables Table 3.1: Recommended levels of general or minimum daylight factor in building.

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Table 3.2: Comparative analysis for different daylight prediction techniques.

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Chapter 1: 1.1. Introduction 1-1-1

Background.

1-1-2

Problem definition & importance of research.

1-1-3

Objective.

1-1-4

Methodology.

1-1-5

Research outlines.

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Chapter 1

1.1. Introduction 1-1-1 Background: The use of electric lighting in homes and at workplaces represents a significant portion of the society's electric energy consumption. At the same time as the electricity flows through lamps inside houses, an overflow of light flows down from the sky and hits the exterior of the same houses. At almost any day the daylight is superior in both the illumination level and the quality compared to the artificial light that is being used for everyday tasks. So why not utilize the daylight instead? And this is actually happen. Daylight and sunlight is let into our building through windows designed both for view and for lighting purposes. Until electrical lighting became efficient and cheap enough in the mid 20th century, the major changes in architecture aimed at letting more light in. This was the objective of the Roman and the Gothic groin vault as well as 19th century Crystal Palace [Lechner, 1987]. In order to fully replace the electrical lighting with the daylight during daytime one step must be taken further than windows and other architectural solution. The question is how to get the light into the building, when windows and skylights cannot do this? [Whitehouse, 1999].

1-1-2 Problem definition & importance of research: Internal lighting has ever been a problem facing architects who try to provide the natural lighting in the space without depending on artificial lighting which is energy consuming. So the most difficult issue in the design is the determination of openings design aspects that influence amount and distribution of the daylight in the space. The main mistake in the design process is the inconsideration of the natural lighting of the space in the initial design stages. As we suppose to take into consideration the orientation of the building in the land to get the best lighting in places needing light at all hours of the day, without being exposed to the glare. We have to consider that sometimes the natural lighting causes some increase in the temperature inside the space and one has this problem wasting energy and money. Another important element for the reflection of the natural lighting is materials used inside the space as it may have a positive or negative action in the resultant light in the space. Eventually , It can be concluded that the kind of glass and the material used in the finishing of the ceiling and floors and walls of the space plus the location and dimension of the openings all these act together as an equation to give the last result for the space and how it may be designed in the first location. In this research we will discuss the design considerations which have to be taken in the determination of size and location of the openings and its material to assure the permanent purpose of the building in hot areas of the world and maintaining it by using the new renewable resources instead of the obsolete consumed ones. (And this will be done by making application methods by supplying some examples and simulating them by simulation programs as "Ecotect"… ect.) As these programs enable us to determine the size and the dimension of the opening and its location , in the initial design stage.

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Chapter 1

As it gives the right value of the percentages of the light in the space and determines whether it gives enough light or not every space by its use. If it wasn't enough the suggestions that will be given for the electrical lightening needed to enable establishing the needed amount of lighting in the space according to its use [The Researcher].

1-1-3 Objective: Reaching the design standards in the determination of the sustainable design aspects in the hot areas. Taking into consideration the dependence of new resources and not the obsolete ones. Discussing methods of using the natural lighting in Egypt and how to use the latest technology in this field [The Researcher].

1-1-4 Methodology: To reach these designing standards for the openings, the theoretical and analytical applications will be discussed which will include the theoretical study of the special definitions of daylight and sustainability showing the ways of classifications specializing in the natural lighting and the divided parts for it. Also showing an examination of the natural lighting and the elements which determine the shape of openings and the mathematical calculations for it. As for analytical application studies, will be shown some examples for the different kinds of buildings such as office buildings and educational buildings and others. In this part, some examples will be discussion from Egypt and other countries dealing with the actual treatments for the natural lighting with a discussion of the new technology in Egypt in these last 5 years. Modeling for the way this buildings Orientation put and designed by making the study by simulation ways used by Ecotect , Daysim and Sky vision programs which will be used to make suggestions of the redesigning of these examples. Also referring to the reason of using these three simulating programs from many others is their accuracy in calculating the natural lighting on scientific basis. These programs will be given to us by Europe National Research Council Canada for natural lighting and this is the main and largest Council in Europe which gives annual reports in this field. Finally a comparative schedule between examples will be issued to support conclusions and recommendations [The Researcher].

1-1-5 The research outline: Three issues will be discussed: First issue: (Theoretically) This part deals with the theoretical analytical study for the natural lighting and the main points affecting it. The study consists of natural lighting background, it's value and the advantages of using natural lighting concluding the physical theories for it.

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Chapter 1

Second issue: (Experimental simulation modeling) This part consists of the applications done on the examples and doing the flow charts to analyze the results and redesign the examples to reach the best solutions. Third issue: (Comparison between analytical evolutions) In this part we will deal with the comparison between the example before and after the redesign reaching the calculation of the daylight amount in the space [The Researcher].

Conclusions: In this part, the recommendations concluded from the applications done will be shown to reach the designing standards considered in the natural lighting designing process [The Researcher].

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Theoretical part Consists of:

1

2

3

Chapter 1

The problem and reaching the designable standards of natural lighting

Background of natural lighting and value of daylight.

Classification of daylight

The reassuring of the mathematical equations for the programs in the theoretical part

The definition of sustainability and its importance and aims in this field

4

Showing the calculation ways of lighting in the space.

5

The effective ways in the amount of light in the space

6

The determination of the methods for solving the light problems in Egypt

7

The determination of the methods which deals with light in Egypt.

The study of the percentage of the sustainability aims established by these examples and how to change these examples to benefit these aims

The analytical & experimental way Consists of:

Showing the simulation programs and why it was chosen. The description of how these programs work "Ecotect, Daysim and Sky vision.

1

2

Making the redesign of Egyptian and European examples together

3

Making comparisons between the examples before and after the redesigning

4

From the results of the two comparison s and comparing them with the previous situations we will decide the weak points and reach the designable standards for natural lighting.

Reaching the final conclusions and the answer to our problems Figure 1-1: The research outline diagram [source / The Researcher].

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Chapter 1

The problem is the inaccuracy of the calculations of the size and the place of the openings and the amount of light going inside the space

1

2

3

4

The reasons which lead to the appearance of this problem and the local examples discussed with the obsolete and recent ways for dealing with it.

How to calculate the needed lightening in the space and how to enter this data in the primary designing process and studying the direction of the orientation of the building and the finishing materials used in it.

The simulating programs done for stimulating and calculating the natural lighting and the measurement of the efficiency of its use in this direction. Plus showing the way of entering the database of these programs and achieving the results and the flow charts dealing with examples in and out of Egypt.

Reaching the recommendations and main aims in the designing of natural lightening in the different kinds of buildings at the end of these results and analysis

Figure 1-2: Methodology diagram [source / The Researcher]..

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Chapter 2: 2-1 Definitions 2-1-1 Sustainability. 2-1-2 Daylight.

2-2 Why daylight? 2-2-1 What is light? 2-2-2 History of lighting. 2-2-3 Value of daylight. 2-2-4 Benefits of natural lighting.

2-3 Advanced Daylighting for sustainable architecture. 2-3-1 Classification of daylight elements. 2-3-2 Advanced technology and those developed in the last decade. 2-3-3 Recent innovative developments in the past 5 years. 2-3-4 Conclusion.

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Chapter 2

2-1 Definition 2-1-1 Sustainability: What is Sustainability? In an effort to clarify exactly what sustainability means, a number of formal definitions and descriptions have been put forward. These range from formulations by the United Nations, to definitions from the perspective of specific academic disciplines, to indexes and lists of principles. So far, there is no universally agreed single definition. But sustainability is a multifaceted concern, so it may well be more productive to look for a defining framework with several dimensions, rather than for a single-point definition. Sustainability is a multifaceted concern, so it may well be more productive to look for a defining framework with several dimensions, rather than for a single-point Sustainability has very broad scope. It addresses almost all aspects of society and extends decades into the future. It is a process for finding solutions to global problems, and it is being put forward as an international strategic agenda. Precisely because of the breadth of these aspirations, sustainability is often regarded as a fuzzy concept which hinders its implementation [Brundtland report, 1987]. A- Definitions from dictionary... Sustainable: (adj) able to be maintained: able to be maintained [Oxford, 1999]. Environment maintaining an ecological balance: exploiting natural resources without destroying the ecological balance of a particular area. B- Definitions of Sustainability by United Nations... This part presents four significant and frequently referenced definitions of sustainability; taken together they represent the range of analytical approaches to sustainability. These are: • A political definition. • A systems definition. • An economic & an ecological definition. A political Definition:"Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs" [Brundtland report, 1987]. Conceptual framework is "Sustainable development, needs, intergenerational equity, limits, economic growth" [Brundtland report, 1987].

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Chapter 2

Our Common Future: Highlights • • • • •

Identifies social and ecological problems as the primary areas of concern. Sees the way society is deploying industry and technology, and distributing their benefits, as both driving and defining these problems. [Identifies] two important sustainability principles: needs and limits. Regards meeting human needs as crucial ... [This] emphasizes the human dimension of sustainable development. "We do not pretend that the process is easy or straightforward. Painful choices have to be made. Thus, in the final analysis, sustainable development must rest on political will" [Brundtland report, 1987].

A Systems Definition:• • •

•

• • •

Achieving sustainability ... mean changing the structure of the system The book Beyond the Limits ... provides a definition of sustainability phrased in the language of systems theory. From a systems point of view a sustainable society is one that has in place informational mechanisms to keep in check the positive feedback loops that cause exponential population and [physical] capital growth. That means that birth rates roughly equal death rates, and [physical] investment rates roughly equal physical. Depreciation rates, unless and until technical changes and social decisions justify a considered and controlled change in the levels of population or capital. In order to be socially sustainable the combination of population, capital, and technology in the society would have to be configured so that the material living standard is adequate and secure for everyone. In order to be physically sustainable the society’s material and energy throughputs would have to meet economist Herman Daly’s three conditions:Its rates of use of renewable resources do not exceed their rates of regeneration. Its rates of use of non-renewable resources do not exceed the rate at which sustainable renewable substitutes are developed. Its rates of pollution emission do not exceed the assimilative capacity of the environment [Ittenbach, Reitmair, 2003].

An economic & an ecological Definition:"Sustainable development requires meeting the basic needs of all and extending to all the opportunity to fulfill their aspirations for a better life". 1- Sees limits as real but conditional ... the continuing availability and extent of natural, renewable resources and "ecosystem services" will be a function of social and technological developments. 2- The concept of sustainable development does simply limits-not absolute limits, but limitations imposed by the present state of technology and social organization on environmental resources and by the ability of the biosphere to absorb the effects of human activities.

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Chapter 2

3- Sustainable development is not a fixed state of harmony, but rather a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional change are made consistent with future as well as present needs [Brundtland report, 1987]. C- Other Definitions based on an individual point of view… There are two ideas hidden in the word system: The idea of a system as a whole and the idea of a generating system. A system as a whole is not an object but a way of looking at an object. It focuses on some holistic property which can only be understood as a product of interaction among parts. A generating system is not a view of a single thing. It is a kit of parts, with rules about the way these parts maybe combined. Almost every “system as a whole” is generated by a generating system. If we wish to make things which function as “wholes” we shall have to invent generating systems to create them. Modified Definition:The systems approach to design and construction for facilities, systems, and equipment that insures consideration of the optimization of ecological and human issues in light of well-grounded acceptable economic constraints. HOK Definition :A balance that accommodates human needs without diminishing the health and productivity of natural systems [Brundtland report, 1987].

AIA (American institute of Architects) Definition:The ability of society to continue functioning into the future without being forced into decline through exhaustion or overloading of the key resource on which that system depends [ Steele, 1998]. Pacific North West National Laboratory:What is sustainable architecture? A basic definition extends that of sustainability itself, an architecture that meets the needs of the present without compromising the ability of future generations to meet their own needs. Those needs differ from society to society and region to region and are best defined by the people involved [ Steele, 1998]. Aspects of Sustainable Design:

Sustainable Design: The Domain. Sustainable Design: Ends, Objectives, and Goals. Sustainable Design: The Process.

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Chapter 2

Conclusions: In this part, from showing for the last definition for sustainable design we can see the following:"Sustainable design is a design philosophy that seeks to maximize the quality of the built environment , while minimizing or eliminating negative impact to the natural environment ".And that gives us the definition of sustainability depends in the first degree on harnessing the natural resources to gain a maximum running efficiency from the building “which lead to minimizing energy consumption” although it's depend on natural lighting with an attempt to minimizing or eliminating side effect such as heat transfers with light and how to store natural light and reuse in other places [Ittenbach, Reitmair, 2003].

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Chapter 2

2-1-2 Daylight: Daylight is constantly changing in intensity and color from dawn to dusk, from day to day, from season to season. Some people consider it a capricious source of light that is best left alone, but it can also be a powerful vehicle of architectural expression. Because it moves, changes character, and varies with the weather, it can provide buildings a living quality unachievable with any other design element. The decision to use daylight in a modern commercial building must be based on more than just an understanding of the aesthetics of light and space; it must be based on an understanding- by the architect and each member of the design team-of the implications of day-light on all aspects of the design, construction, and use of a building. Daylight can affect the functional arrangement of spaces, occupant comfort (visual and thermal), structure, and energy use in the building, as well as the type and use of electric light and associated control systems. In fact, if daylight is considered a viable source of light in the building, its use can have ramifications for all aspects of the building design process, from urban planning to interior design, from predesign analysis and programming to specification writing and construction. No phase of the building design process will be unaffected. Daylighting is both an art and science; that is, daylight is both a design element and an environmental system. As a design element, it can enhance aesthetic and qualitative aspects of a building. As an environmental system, it should be subjected to the same level of rigorous analysis and review that any environmental system receives. To work as design element, it must be made as integral part of one's design philosophy. To work as an environmental system, its performance attributes (including lighting, energy, and economics) its physical characteristics, and its interaction with other environmental system (including electric light, heating, cooling and building structure) must be described usually quantitatively. The combined consideration of design and environmental system purposes is part of the building design process known as design synthesis. Although daylighting may sometimes be considered exclusively in terms of design aesthetics, it is more often considered as a design alternative because of some concern for energy use and energy conservation in the proposed building. Recognizing that daylight is both design determinant and an environmental system does not begin to explain why it should be included in the building, how it has been used in the past, or how it fits into the building design process. These kinds of questions are important because (rightly or wrongly) daylighting is considered an alternative technology, just as electric lighting was as an alternative to day lighting 100 years ago [ L.Robbins, 1985]. In order to begin considering the inclusion of daylight in a building, a designer must have one or more compelling reasons for doing so. Most often daylight is used as either a primary or a secondary interior illuminant; but even if it is used only to provide a particular design effect, the designer must consider the impact of the light on all aspects of the building and its occupants. Every building has different requirements, needs and constraints. The decision to use daylight, or any other specific environmental system, must be made on a case- by-case basis. In order to make good professional decisions, the designer should consider all pertinent issues and weight them in terms of the requirements of the project.

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Many reasons can justify considering daylight as a light source in both residential and commercial buildings, although some of the reasons may apply more to one building category than the other. Among the reasons are: • • • • • • • • • •

Quality of the light. Importance of daylight as a design element. View (daylight apertures provide visual communication channels to the outside). Use of day lighting apertures as fire exits in emergencies. Energy conservation resulting from the use of daylight as a primary or secondary illuminant. Energy consumption and peak demand cost savings resulting from the use of daylight. No cost change in construction. Opportunity to develop integrated structural and mechanical systems. Psychological and physiological benefits not obtainable with electric lighting or windowless buildings. The genuine desire to have natural light and sunlight in a room or space. The quality of daylight as a illuminant is an important reason to use daylight in a building. Daylight the combination of sunlight and sky light-is the one light source that most closely matches human visual response. Daylight is a full- spectrum light, over millions of years; the human eye has evolved using this full-spectrum light as the source against which all other light sources are compared [ L.Robbins, 1985].

Technical issues of daylighting design: At least five primary technical or design issues must be described, understood and accepted before day lighting can be fully utilized as a building-environment technology. These issues are: • • • • •

The need for a daylight- and sunlight-availability data base for analyzing lighting and energy performance characteristics of the system and building. The need for a systematic method of describing day lighting concepts (in order to develop design intuition about the best ways to use daylight in buildings) The need for comprehensive methods of analysis that include all aspects of system performance (illumination, energy, and visual comfort). The need for a method of integrating day lighting and electric lighting. The need for better understanding of who has responsibility for the design of the day lighting system the architect, the engineer the lighting designer, a day lighting consultant, or a combination of these [ L.Robbins, 1985].

Under and over – estimation of day lighting design :Daylighting concepts need to be developed on the basis of the designer's having some understanding of the sensitivity of the system to change. It is important when designing a day lighting system not to be overly concerned about detail early in the design

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process. Like the structural system, the HVAC systems, and the exact arrangement of spaces in the building, the day lighting system should not be completely designed until the end of the design process [ L.Robbins, 1985]. Many architects and engineers follow a building design process that includes the following five steps (fig 2-1) (fig 2-2): • • • • •

Schematic or conceptual design. Design development or final design. Documentation or working drawings. Bidding. Construction.

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PDA

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Figure 2-1 typical linear building design process used by Many architectural firms: (a) Redesign analysis (PDA); (b) Schematic design (SD); (c) Design development (DD);(d) Construction documents (CD); (e) Construction( c) [source / L.Ronnins, 1985]

SD

DD

CD

C

Daylight Concept Development and Daylighting Systems Design and Analysis

Is Daylighting available Lighting Alternative?

Redesign Analysis

1. Site Consideration 2. Program Considerations 3. Utility and Energy Considerations

Figure 2-2 Steps in the redesign analysis phase of the Building design process for using daylight in a building [source / L.Ronnins, 1985].

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2-2 Why daylighting? 2-2-1 What is light? Light is purely a human sensation in similar fashion to sound, taste, smell and warmth. Something is necessary to stimulate the senses, and in this case it is electromagnetic radiation falling on the retina of the eye. Light can therefore be considered as a combination of radiation and our response to it. The brightness of light as we humans experience it depends on the surrounding. If the eye is kept in a low light situation for some time the eye grows more sensitive and a given quantity of light will seem brighter than normally [ Gordan, 1957 ].For this reason there are standardized mathematical descriptions of visual sensitivity. These interrelated units describe the flow of the light , its intensity in space, luminance at the point , and the luminance of a surface . These units are both physical and psychological, since they depend on both the physical properties of electromagnetic radiation and our perception. Luminous flux describes the total flow of a light from a light source. The output of a lamp is given in lumen (lm). The luminous efficacy gives us the relation between a lamp's light output and its electrical input. The intensity of the light, from a source, in a certain direction is defined as luminous intensity with the unit candela (cd). The amount of light falling on a unit surface area is the luminance measured in lux (lx) [Tregenza and Loe , 1998 ] .

2-2-2 History of lighting. In the early history of the humans, the sun was the only light source. Around 400 000 B.C. the human discovered the fire and learnt how to control it. The flaming torch and campfire constituted the first use of artificial lightening. The first lamps were quiet primitive and made of naturally occurring materials, such as rocks, shells, horns and stones. These lamps were filled with grease and had a fiber wick. They typically used animal or vegetable fats as fuel. Basic designed lamps and pottery lamps followed the natural oil lamp. These were invented in the early Greek time. In the beginning they were handmade and later they were manufactured. Pottery lamps provided a cheap and practical mean of illumination, easy to produce, easy to use, but rather messy to handle. The oil would often goes from the weak hole and run down the side of the lamp. The invention of the candles dates back to about 400 A.D. , perhaps somewhat earlier. Candles were rarely used in the home until about the 14th Century, however they were an important symbol of the Christian religion .The best candles were made of bee wax and were chiefly used in church rituals because the bee was regarded as a symbol of purity. William Murdock a Scotsman is generally regarded as the father of gas lightening. In 1792 he heated coal to produce gas and used it to light his home and office on Cornwall, England. Thomas Edison invented the first practical electric lamp in 1879. Edison's original lamp used a carbon filament placed in vacuum. Today's light bulbs contain a tungsten wire and argon gas. Edison's original lamp converted less than 1% of the electricity into light. Today's household bulbs convert 6 to 7% into light, the rest being wasted as heat. Compact fluorescent lamps today can be 50 times more efficient then Edison's original lamp and last for years. Today there is an increasing amount of lamp types available for home, work place and exterior lighting. In addition small businesses, such as retail stores and

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restaurants are finding that well designed lighting can have a significant effect on the customer's view of their products and their establishment [Williams, 1999].

2-2-3 Value of daylight. Daylighting has become increasingly important in buildings, in part because it is recognized as related to improved morale and productivity of the people, which are working or living, in such buildings. No electrical lamp can match the color variation of daylight. The human eye adapts easily to daylight and especially windows give the occupants a sense of contact with the outdoors [US Department of energy, 2002]. The information that our brain receives from the illuminated environment is an essential element in shaping our moods, reactions and psychological well being [Sze-Hui, 1999]. So, physiological and psychological benefits are good reasons for using natural light. Daylight generally increases occupant satisfaction by providing a healthier and more pleasant environment. It seems like humans function better emotionally and physically under natural light, it seems like our bodies were designed for natural light. By receiving the full spectrum light the human body gets beneficial effects like producing more vitamin D, gets a better calcium absorption, metabolism and hormone secretion. The body's ability to assimilate calcium is essential for formation and maintenance of bones and teeth and it depends on the presence of vitamin D. A healthy person receives enough of this vitamin through a daily exposure of the hand and face to 15 minutes of sunlight. Of coarse we get some vitamin D from food, but up to 90% of the vitamin D on our body is built up by the reaction that occurs when our skin get exposed to ultraviolet light, which is present in e.g. sunlight. Children with softening bones or old people with brittle bones have problems with vitamin D insufficiencies, which can be prevented or even cured by exposure to small quantities of ultraviolet radiation [Neer et al, 1971]. Recent Swedish studies have shown that people in the northern part of the country more often get hip fractures than people in the southern part. This is thought to be caused by the lack of exposure to sunlight, and thereby lack of vitamin D [William- Olsson, 2002].A study on daylighting in schools shows that students get more productive in daylighting schools, than in traditionally illuminated schools. Students with optimal day lightening in their classrooms progressed 20% faster on Mathematics tests and 26% faster on reading tests in one year, compared to students in the least day lighted classrooms.[Plympton et al, 2000]. Students tend to be more attentive and display lower levels of hyperactivity [Thayer, 2000].An analysis by Nicklas and Bailey shows that students exposed a full spectrum of light were healthier and attended school 3.2 to 3.8 days more per year, than students at comparative nondaylighted school. The full spectrum lighting induced more positive moods and because of the additional vitamin D received by the students in full spectrum light, students had nine times less dental decay, than students in a nondaylighted school [Nicklas and Bailey, 1997].Libraries with superior light resulted in significantly lower noise levels. Daylighting bring the effect that heating, ventilation and air condition systems can be downsized, which also reduced the noise levels in offices, classrooms and library, thus enhancing the environment for working and studying [Plympton et al, 2000]. Another primary difference between natural and artificial light is the inherent variability of daylight and its unpredictability. Levels fluctuate as clouds move through the sky, successively obscuring and revealing the sun. some studies have showed that this variability of the daylight has a relaxing effect on the eyes [Sze-Hui, 1999].Daylight has a better " light quality " than electric light. Light quality is a holistic term which includes a number of attributes of the

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environment that are generally considered to be positive, like better distribution of light, better color radiation, absence of flicker. Daylight is a very diffuse source of light, and tends to illuminate surfaces more evenly in all directions. Electric lighting for offices or schools is mostly designed so the light is directed downwards towards the desktops. For that reason the horizontal surfaces are brightly illuminated than vertical surfaces. The stronger horizontal component of day light improves visibility. Therefore daylight has a better distribution of light. Colors look more natural in daylight than under electrical light, as most electric light sources are stronger in some areas of the light spectrum and weaker in others. Daylight on the other hand has continuous spectrum and therefore provides better color rendition. Colours tend to look much more vivid in daylight. Daylight does not flicker; fluorescent lamps can have a noticeable flicker. People blame this flicker for a multitude of problems, like headaches, eyestrain and attention deficit problems. Fluorescent lights that run on electronic ballast, have considerably reduced flicker problems, but only daylight guarantee a total absence of flicker. Another aspect of "lighting quality" from daylight is sparkle or highlights on three- dimensional objects. Artists like to have a daylight studio partly for the way shadows and highlights make objects more attractive and easier to understand three dimensionally, and a lot of the artists see a certain richness of their design in the variability of the light [Plympton et al, 2000].All the benefits of daylight will not be present when sunlight is piped, as the ultraviolet and infrared rays probably will have to be eliminated before the sunlight can be piped.During cloudy days we have to add artificial light, which remove the guarantee of total absence of flicker. But even if we do not get all the benefits of the daylight if it is piped, it would be an improvement if we just get some benefits. .

2-2-4 Benefits of natural lighting. One important benefit of daylight aperture is that they provide visual communication channels to the outside; that is, they offer the building's occupants a view (Manning 1967). In many of the studies of windowless spaces, the people occupying those spaces repeatedly express a desire for contact with the external world. Although the desire for a view seems important, there is less understanding of what makes a good view and whether a good view is necessary. In one extensive survey, Markus assessed the view preferences of some 400 English office workers from Bristol [ Markus 1967 a; Markus 1967b]. Approximately 70 percent of the office workers rated their view as good, and 25 percent rated as adequate. A large majority (some 88 percent) preferred a view of the city or of a distant landscape. Only about 12 percent preferred a view of the sky alone or of the ground level of surrounding buildings. Many of those interviewed who sat some distance from an aperture greatly desired to be nearer to it. Markus also discovered that the need for view-and even the need for sunshine-could rate fairly low on a list of desirable environmental factors if these attributes were already being provided adequately. Thus subjects who already have daylight and a view might suggest that these are not important, while people who have what they believe to be an inadequate view and insufficient access to light rate it quite high on their list of desirable environmental factors. Markus felt that a variety of apertures could be used to provide workers with an optimum vies. Vertical apertures provide a view of the sky ( an upward view), the city or landscape ( a horizontal view ) and the ground ( a downward view) ; however, some of these views can be provided by other types of daylight apertures, such as angled wall or roof apertures or horizontal roof apertures for illumination can be supplied by separate forms in a certain

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design situations. In a survey by Cooper et al. of English office workers, only 3 percent felt that good view out was the most important feature of a pleasant office environment [Cooper et al. 1973]. A majority indicated, however that a view of a variety of distant objects made the view a more important feature. In addition, the height above the ground of the subject's office and the age of the subject seemed important- the former because the offices considerably above the ground level have a view of more distant objects, and the latter because people on different age groups need different quantities of light in performing the same visual task. As the human eye ages the inflections within it form various light sources have a significant impact on vision .The size of aperture needed to provide an acceptable view out has also been studied. Ne'eman and Hopkinson conducted research on the fraction of a window wall aver which glazing is necessary to provide an adequate view out [ Ne'eman and Hopkinson 1970 ]. Some 50 percent of the subjects felt that the smallest desirable aperture was equal to 25 percent of the window wall. When the window was increased to35 percent of the window wall, some 85 percent of the subjects found the aperture area to be adequate. Another conclusion was that, if total window area must be limited but multiple apertures are possible they all should fall within the cone of view of 60º or less.Keighley studied apertures amounting to less than 20 percent of the window wall and found that many of the subjects were dissatisfied with such small apertures [Keighley 1973a; Keighley 1973b]. When the aperture was very wide in comparison to its height and still amounted to less than 20 percent of the window wall, however, the subjects found it more acceptable.Keighley concluded that a wide window provided a desirable lateral scan- one allowing the room occupant a more extensive view of the landscape but a more restricted view of the sky or ground. Keighley also studied groupings of such wide apertures and found that the subjects disliked grouping of that type of aperture. Further using several small windows of different shapes was found to be very unsatisfactory, and using combinations of different aperture sizes was found to be impractical in any lighting situation in which the entry of daylight into the space was an important design criterion. Another important benefit of a daylighted building is the availability of daylight apertures for use as fire exits during emergency. Daylight apertures, especially windows, can be used as fire exits even if they are not the preferred means of egress [Griffith, 1962]. After the reviewing a number of serious fires in windowless buildings, Juilliard concluded that their severity was exacerbated by the inability of occuoants to open windows to vent smoke, let people escape, or allow firemen to enter. Moreover, the total reliance upon electric lighting and mechanical ventilation in a windowless building means that any emergency involving a loss of power can create a dangerous situation unless auxiliary power is immediately available [Jiillerat 1964]. Daylight can significantly reduce energy consumption and peak energy use in commercial buildings. Because 30 to 50 percent of the energy used in a commercial building are spent on illuminating the interior of the building, anything that can reduce the need for electric light will significantly lower the energy requirements of the building. In a correctly designed daylighting system that incorporates energy conservation in the design criteria, the electric light will be turned off, stepped down, or dimmed whenever sufficient daylight is present to provide task or background illumination. In this way, energy conservation can be achieved for lighting energy use, cooling energy use and peak electric energy use (see fig. 2-3).It is reasonable to expect that daylighting can reduce the need for electric lighting in a building, but this does not mean that daylighting replaces electric lighting systems. It only means that the electric lighting does not have to be used when daylight is present in sufficient quantities. When insufficient daylight is present because of weather or time of

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day (or night) - the electric lighting system will be needed. The key to designing an integrated (daylight + electric light) lighting system is the electric lighting control strategy. Light, whether it is daylight or electric light, adds heat to a building. That is because most lighting systems are very inefficient: in order to produce light, they must also produce heat. In the case of incandescent light, only about 10 percent of the input energy is emitted as light; the rest is converted to some form of heat , usually in the near infrared. In the case of florescent light, about 20 to 35 percent of the input energy is emitted as light. Daylight also adds heat to a building; about 55 percent of the thermal energy in solar radiation is in the visible spectrum.

Figure 2-3 Energy use and costs in a typical office building. In this case the same building has been analyzed in ( a ) Denver, Colorado, and ( b) Pittsburg, Pennsylvania, for ( h) heating, ( c ) cooling. ( I ) lighting, and (m) miscellaneous [source / L.Robbins, 1985].

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2-3 Advanced Daylighting for sustainable architecture The design of a daylighting space is both an art and a science. The biggest challenge facing the lighting designer is to admit only as much light as necessary and distribute it evenly throughout the space without introducing glare or heat. In hot / warm climates, it has become common practice in windows spaces to specify blinds and glazing with high shading coefficients to control glare and minimize heat gain. However, this practice reduces the effectiveness of lighting systems that dim automatically. Improved systems are needed to capture natural daylight and distribute it uniformly throughout a space while controlling heat gain and glare. One such system is the light shelf. Light shelves shade the space from direct sunlight and reflect this sunlight onto the ceiling for a deeper and more uniform distribution. While this is not a new idea, little unbiased empirical data has been collected, outside the laboratory that compares the performance (energy savings, uniformity, and level) of an automatic daylighting system [Aboulnaga, 2003].

2-3– 1 Classification of daylight elements: In order to classify the daylighting components it is important to distinguish between two main groups which are "Conduction components ","Pass-through components" and " Control Elements ". The conduction component can be defined as a space designed to guide and / or distribute daylight towards the interior of a building from one pass-through component to another. Basically, there are two groups of this type: 2-3-1-1 Conduction Component: 2-3-1-1-a- Intermediate light space. 2-3-1-1-b- Interior Light space. . 2-3-1-2 The Pass-through Components are identified as three groups as follows: 2-3-1-2-a- Lateral pass-through component. 2-3-1-2-b- Zenithal pass-through component. 2-3-1-2-c- Global pass-through component. 2-3-1-3 Control Elements These three groups component may incorporate control elements such as: 2-3-1-3-a- Separator surface. 2-3-1-3-b- Flexible screens. 2-3-1-3-c- Rigid screens. 2-3-1-3-d- Solar filters. 2-3-1-3-e- Solar obstructers.

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2-3-2 Advanced technology and those developed in the last decade: Innovative daylighting systems are designed to redirect sunlight or sky light to areas where it is needed with excessive luminance and glare. These systems use optical devices that initiate reflections, refractions, and / or use total internal reflection of sunlight and sky light. Advanced daylighting systems can be designed to actively track the sun or passively control the direct sunlight and sky light. In 1995, many advanced systems emerged as a new element of design to achieve that [Aboulnaga, 2003]. Types of advanced Daylighting systems should be selected according to climate characteristics e.g. the predominant sky type, and latitude at the building site. The state of the art of designing daylight building varies widely with climate and latitude. These types are classified according to the following: 2-3-2-1 Shading Systems Using Diffuse Light: 2-3-2-1-a- Louvers / Blinds 2-3-2-1-b- Automated Blinds. 2-3-2-1-c- Optical shutters. 2-3-2-1-d- Holographic Optical elements (HOE) Shading systems. 2-3-2-2 Shading Systems Using Direct Sunlight: 2-3-2-2-a- External Light Shelves. 2-3-2-2-b- Internal light shelf ( redirecting daylight). 2-3-2-2-c- Angular selective Skylight. 2-3-2-3 Non-Shading Systems Using Diffuse Light: 2-3-2-3-a- Anidolic ceiling. 2-3-2-3-b- Zenithal Light guiding glass with (HOEs.) Holographic Optical elements. 2-3-2-4 Non-Shading Systems Using Direct Sunlight: 2-3-2-4-a- Laser-cut panels. 2-3-2-4-b- Prismatic panels. 2-3-2-5 Other Systems: 2-3-2-5-a- Light pipes (duct / well). 2-3-2-5-b- Switchable Electrochromic or gas chromic window coatings. The following buildings example featured the advanced technologies of daylighting elements of worldwide buildings which incorporating these innovative systems [Aboulnaga, 2003].

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2-3-2-1Shading Systems Using Diffuse Light A daylighting system should be selected according to climatic characteristics, e.g., the predominant sky type and the latitude at a building site. Actual energy savings depend on the daylighting system being designed as part of an integrated strategy that includes daylight-responsive controls. Careful integration of the daylighting system with the rest of a building’s design should begin early in the design process to produce a high-quality work environment and provide building owners with a highly valued space. 2-3-2-1-a- Louvers / Blinds. Louvers. Fixed, mirrored louvers are designed principally for direct sun control. High altitude sun and skylight reflected off the louvers increase interior daylight levels. Daylight levels from low-altitude skies (i.e., from the region of the sky approximately 10° to 40°above the horizon) are reduced. Fixed, mirrored louvers such as the “Fish” or “Okasolar” system can control glare but reduce daylight levels. They are a design option for shallow rooms in temperate climates [Aboulnaga, 2003]. Blinds. Standard Venetian blinds provide moderate illuminance distribution. The optimum amount of slat closure is dictated by glare, direct sun control, and illumination requirements. Inverted, silvered blinds increase daylight levels if the slats are horizontal .

Figure 2-4 – Yasuda Academia building, Figure 2-5- The Scottish Office building Tokyo, japan. Edinburgh , UK. Daylighting is achieved via solar glazing Daylighting is achieved via triple glazing Solar glazing / blind / louvers [source / http:// www .greatbuilding.com].

Figure 2-6- Shows a shading technique, PFIZER building 500, UK as Green building ( Courtesy of FOCCHI,Uk) [source / Aboulnaga, 2003].

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2-3-2-1-b- Automated Blinds. Window treatments are specially designed to include motors that perform the same functions you would have performed manually. The motors that move the drapes or shades are concealed within the valance at the top of the window treatment. Wall switches, infrared remote controls, or electrical relays are used to trigger operation. The electrical or infrared control commands for the window coverings are integrated into your Home Theater remote controller or your Home Management System (Fig. 2-7and 2-8).

A-BRE building, Gars ton, UK.

B-Herman Miller SQA HQs.,Holland

C-San Francisco Public. .Library, US.

Figure 2-7- Shows examples of automated blinds / louvers [source / http:// www .greatbuilding.com].

Solar shading panels.

Solar shading panels.

Menara Mesiniaga Bldg Malaysia.

Commerzbank HQ Building , Germany.

Figure 2-8- llustrates Daylighting elements as solar shading panels [source / http:// www .greatbuilding.com]. 2-3-2-1-c- Optical Shutter. In 1998, the high-tech daylighting active optical façade was part of the building design scheme by noted French architect Jean Nouvel. The collective effect of these hightech stainless steel irises is a rich optical brocade, strongly but abstractly evoking the beautiful patterns of traditional Arabian weaving. This metal sunscreen (Fig.2-9 integral to the curtain wall provides active sun screening.) [Aboulnaga, 2003].

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Figure 2-9-The Optical sunscreen, Institute De Monde Arab, Paris France [source / http:// www .greatbuilding.com]. 2-3-2-1-d-Holographic Optical Elements (HOEs) shading systems The HOEs is an element that bends the light by diffraction. The principle of this technology is that the window are coated with transparent coating in which an invisible diffraction patterns is printed by holographic technique (fig. 2-10- a & b). .From the functional point of view, the window will then deflect transmitted direct and diffuse solar radiation (sunlight)over a well defined angle (defined by the diffraction grid characteristics) deep into the building. Similar grids can be also be used to reflect away solar light which impinges on the window from well defined angles (fig. 2-10). The design, the diffraction pattern of transmittance and reflection holograms has to be defined before recording. Light then emerges at a set exit angles. One of the prime advantages of the HOE is the reality that, unlike other conventional optical elements, their function is essentially independent of substrate geometry [Aboulnaga, 2003].

a- Diffraction of light using b- Two-dimensional performance c- Function of HOE in HOE. of top lighting using two layers of HOE. design.

Figure 2-10- Shows how HOE performs to direct light [source / Aboulnaga, 2003].

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2-3-2-2 Shading System Using Direct Sunlight As with any kind of daylighting, the daylight entering the space becomes heat energy. This increases the cooling load in warm weather and reduces the heating load in cold weather. Light shelves disperse sunlight fairly efficiently, so the amount of heat energy added to the space is not much greater than would be added by an equivalent amount of electric lighting. (This is true of electric area lighting. Electric task light is much more efficient in terms of localizing lighting energy.) [Aboulnaga, 2003]. 2-3-2-2-a- External Light Shelves An external light-shelf is simply a horizontal or tilted plane inserted within a window to effectively divide it in two. It is an opaque element with a highly reflective upper surface and diffusing white under-surface. It is positioned such that there is sufficient area of window above it to allow the reflection of both sunlight and daylight light directly up onto the ceiling with in the space whilst not obstructing view through the window. External light shelves are used to improve a lighting by reflection and provide a virtual sky to spaces during overcast sky and for obstructive building (fig. 2-11 a). Another example of the use of this technology is shown at Ash Creek Intermediate School in Monmouth, Oregon. This was based on a study carried out to evaluate the lighting system at the school. The lighting in the classrooms was slightly uneven this includes the luminance from all sources (daylight and electric) in a south-facing classroom. While the electric lights are the greatest single source of illumination, the daylighting, on a sunny day, easily matches the strength of the electric lights. The study examined the viability of daylight to provide adequate and even lighting using several new technologies such as external light shelves (fig. 2-11 b). In 1996, the Inland Revenue Castle Meadows, Nottingham, UK exhibits an example of this technology as solar heat gain reduced using external light shelves, triple glazed windows, and electronically controlled blinds. The buildings management system automatically sets levels of heating, lighting and ventilation (fig. 2-11 c) [Aboulnaga, 2003].

a) A Victorian Building in London City

b) views of Ash Creek Intermediate School, Oregon,USA.

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c) Different view of Inland Revenue Castle Meadows – Nottingham, England. Figure 2-11- Shows how External Light Shelves are used to improve daylighting by reflection [source / Aboulnaga, 2003]. 2-3-2-2-b- Internal Light shelf (Redirecting Daylight) In many cases daylight distribution in a typical side lit room is very uneven, with very high level of daylight in the window zone and very low level in the rear zone of the room. A lightshelf can be used to even out the Daylighting. It is usually placed in a nearly horizontal position between lower and upper part of the window. It functions as sun shading for the lower part of the window, reducing Daylighting in the window zone. Light, which is reflected to the ceiling, increases the daylight in the rear part of the room (fig. 2-13). • On a site with predominantly clear sky with sun, both inside and outside light shelves can be used. The outside lightshelf functions better as sun shading. A specular lightshelf reflects daylight more effectively. If there is a danger of solar glare, a diffuse material is recommended. The slope of the lightshelf should be designed independent of the main solar altitude and geometry of the room. • For a site with predominantly overcast sky conditions and for north-facing windows a specular outside, sloped lightshelf is recommended. The WAT Office building in Germany exhibits the use of lightshelves to redirect light and improve its distribution (fig. 2-12 a). In 1994, a low energy office building (CEWHQ) was constructed that reflected the ecological commitment of the building owner. The design concept consists of the following components: Daylighting optimized by using light shelves; and daylight controlled artificial lightening (fig. 2-12 b) [Aboulnaga, 2003].

a) Office Building WAT, Germany.

b) Incorporated lightshelfs: Corporate Express World Headquarters. Figure 2-12 Shows external and internal views of light shelves to improve daylighting condition [source / Aboulnaga, 2003].

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Figure 2-13 Shows different types of light shelves set up at both clear and overcast sky conditions [source / Aboulnaga, 2003]. 2-3-2-2-c- Angular Selective Skylight The powerful light deflecting power of laser cut panel may be used to form glazing which, depending on the angle of the incidence, selectively reject or admit light. Two types of glazing have been developed, one for skylights and one for conventional windows. The angular selective skylight was developed to improve the performance of ordinary skylights and atrium glazing. Generally, skylights admit too much sunlight near noon in summer when the sun elevation is high, leading to overheating of the building.

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Conversely when the sun elevation is low, in winter, early morning and late afternoon, a conventional skylight transmits very little of the incident sunlight to the building below. This situation can be rectified by using laser cut panels in a pyramid or triangular form over the skylight aperture. Now high elevation light is deflected back upwards to the sky and low elevation light is deflected down through the skylight aperture. The angular selective skylight is marketed in a size range from 0.8m square to 2.4m square (fig.214&2-15) [Aboulnaga, 2003].

Figure 2-14 Angular selective skylights on Figure 2-15 Rejection of high elevation A building at Waterford state school light admission of low elev. Brisbane Australia. Light by an angular selective skylight

a) Sidney’s Star City

b) St. lves Shopping Center c) Westfield Shopping Center

Figure 2-16 Angular selective skylights/sky domes as daylighting elements [source / Aboulnaga, 2003]. 2-3-2-3 Non-Shading systems Using Diffuse Light 2-3-2-3-a- Anidolic Ceiling To clearly mark the use of nominating optics principles for the design of such systems, they are named "anidolic" is a synonym of "nonimaging", constructed from two words of ancient Greek ("an" = without, "eidolon" = image) .The Anidolic Ceiling (AC) was built in 1996 and installed on a mobile daylighting test module located on the EPFL campus. It uses a light duct into a ceiling to guide a large flux of daylight into a 6.55 meters deep office space (3.05 x 6.55 x 3.05 meters). Its design had to meet the following requirements. All the internal surfaces of the AC were covered with highly reflective optical material (post-anodized aluminum foils of 0.93 regular reflectance). The device is covered with an insulated double glazing at the entry aperture; a single pane, made of organic material,, was placed at the exit aperture ( Figure 2 – 17 ). This device collect

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sunlight falling on an entry aperture and concentrate it on a smaller exit aperture where the receiver is placed (e.g. a heat exchanger on a photovoltaic cell) reaching concentration factors close to the thermodynamic limit. When the light ray paths are reversed by replacement of the receiver with a light emitting source, the same kind of device can be used as a highly efficient luminiare capable of delivering light through beams of well defined angular spread. This could be used to control sunlight and diffused one and also re-direct the reflected light deeper into the space. As shown in (Figure 2-17 b ), It increases the level of illuminance in deeper room 6.00m or more where more than half the space experiences low level of daylight . The Anidolic Ceiling was used in Brussels, Belgium for the refurbishment of Caisse-Conge building. The project was carried out by the architects Philippe Samyn and partners. This project, which won the second prize of the project competition, accounted for an Anidolic Zenithal Collector to improve the daylight penetration into the building. The assessment of the daylighting performance of the anidolic device, carried out by the Belgium Building Research institute, confirmed the outstanding features of the Anidolic Zentithal Collector with regard to daylight penetration into deep rooms [ Aboulnaga, 2003]

Figure 2-17 Horizontal and ceiling Anidolic duct [source / Aboulnaga, 2003].

Court yard in the Caisse-Conge Refurbished building, Brussels, Belgium. Figure 2-18 A view of an Anidolic Ceiling incorporated in to a courtyard to improve daylighting [source / Aboulnaga, 2003].

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2-3-2-3-b- Zenithal Light-guiding Glass with (HOEs.) Holographic Optical elements.

Figure 2-19 Shows Zenithal Light-guiding Glass [source / Aboulnaga, 2003]. The 1st curve reflector concentrates all incoming light from half the sky into a smaller vertical opening in plane of facade. The light rays are then shaped into a beam of well-defined angular spread using 2curved reflectors mounted face to face (figure 2-19 a). The ray paths through the Anidolic zenithal collector for different sunlight ray at different time of the day-early morning and noon time-(figure 2-19 b-c). Shows a cross- section showing an Anodolic zenthial opening. This could be used on the roof of buildings to attract daylight (not sunlight) and maximize the light level into spaces with low illuminance and also have no direct accesses to daylight [ Aboulnaga, 2003]. 2-3-2-4 Non-Shading Systems Using Direct Sunlight In general, among the systems tested, some, such as the selective shading systems that reconcile solar shading and daylighting, can save significant energy. Non-shading daylighting systems that are located above eye level and redirect sunlight to the room ceiling, such as laser-cut and prismatic panels, can save considerable electrical energy but require detailed design consideration, e.g., specific tilting to avoid glare. Under overcast or Cloudy sky conditions, anidolic systems perform well. 2-3-2-4-a- Laser-cut Panels The laser-cut panels is new advanced system comprise of elements made using laser technology that produces a series of fine parallel cuts in acrylic panels. This process results in arrays of transparent parallel pipes, with the cuts acting as a series of small reflectors with total internal reflection occurring as their surfaces. Usually these panels are placed inside double-glazing units (figure 2-20,2-21) [ Aboulnaga, 2003].

Figure 2-20 The British Airway terminal using the Laser-cut panel ,London ,UK.

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Figure 2-21 The laser-cut panel installed in school classroom in Australia [source / Aboulnaga, 2003]. 2-3-2-4-b- Prismatic Panels The function of the Prismatic panel is to control the transmission of light by refraction. The direction of incoming daylight is altered by passing through a prism or a triangular wedge of glass. Normally a prismatic system which will refract the light to ceiling point consists of two sheets of prismatic panels, with the prismatic face located internally for dust protection ( figure 2-22 a,b,c).

Figure 2-22 Prismatic Panels to Control Sunlight [source / Aboulnaga, 2003].

Figure 2-23 Prismatic Panels to Control Sunlight [source / Aboulnaga, 2003]. One of the types of the innovative prismatic panel is a triangular daylighting system comprising of 2 Prismatic components and a Reflector. The 1st prismatic element rejects sunlight while admitting light rays from high altitudes. The 2nd one redirects the

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light mainly towards the ceiling of the space. It is clear that the triangular daylighting system can be adjusted to work under different angles to better function (figure 2-23 a,b). Prismatic panel for daylighting were used in Berlin in 1974. Poor quality lightening led to this development of prismatic panels. Further investigation of the idea has brought about two forms of prismatic glazing. • •

Sun-screening Daylight control and distribution 2-3-2-5 Other Systems.

There are another systems we can use to reduce glare and heating and to reach the light to maxima are we can, from these systems one called "light pipe" As the name implies, light pipes convey light to locations within the building where it is needed. Many types of light pipes have been designed, but only a few are commercially available. Some claims made for light pipes defy the laws of physics. A light pipe cannot deliver more light energy to the space than it collects on the outside of the building. At present, commercial light pipes do not concentrate sunlight from large exterior collectors into smaller pipes. Understand the principles of light pipes so that the installation will yield the results you expect [ Aboulnaga, 2003]. 2-3-2-5-a- Light pipe (duct/well) The light duct consists of a pipe, covered by reflecting material, with a clear acrylic dome polished aluminum interior and translucent ceiling diffuser. This could be used on the roof of buildings to attract daylight (not sunlight) and maximize the light level into spaces with low illuminance and also have no direct accesses to daylight. The light pipe is a very useful system for underground building or basements where high illuminance is required to compensate for the low level of daylighting (figure 2-24 a,b). For a room 3.6x2.3m is illuminated by four 330mm diameter vertical light pipe with clear external dome and diffusers in lower aperture measurements showed that with outside illuminance level of 16Klux the average internal illuminance was 177lux an effective Daylight factor (DF) of 1.1%. DF ranges from 1-5. the average DF for airport, general buildings, libraries, museums & art galleries, schools, residential buildings require 2,2-5 , 3-6 , 5 , 5-6 , 1-2 respectively. The range depends on the space type like offices; drawing rooms require average DF of 5 (figure 2-25) [ Aboulnaga, 2003].

a- A lobby outside an office. b- a meeting room lighted by virtue of a light pipe. Figure 2-24 Shows daylighting by using light pipes [source / Aboulnaga, 2003].

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Figure 2-25 Zenithal light pipes (sky dome) with movable reflectors [source / Aboulnaga, 2003]. 2-3-2-5-b- Switchable Electrochromic or Gasochromic Window coatings. Smart windows (active façade) and shading systems have optical and thermal properties that can be dynamically changed in response to climate, occupant preferences and building energy management control system (EMCS) requirements. These include motorized shades; Switchable Electrochromic or Gasochromic windows coatings, and double-envelope macroscopic window-wall systems (figure 2-26 a,b). Smart windows could reduce peak electric loads by 20 – 30 % in many commercial buildings and increase daylighting benefits through out the U.S., as well as improve comfort and potentially enhance productivity in our homes and offices. These technologies will provide maximum flexibility in aggressively managing demand and energy use in buildings in the emerging deregulated utility environment and will move the building community towards a goal of producing advanced buildings with minimal impact on the nation's energy resources [ Aboulnaga, 2003].

a- BRE Building, UK.

b- Show LBNL Electro chromic test Facility, Oakland Federal Building. Figure 2-26 Daylighting via Electro chromic glazing [source / Aboulnaga, 2003].

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2-3-3 Recent innovation developments in the past 5 years (2000-2005): The array of advanced technological solutions presented in the prior section is tantalizing to the innovative architect and engineer. Clearly, the process needed to achieve high-performance in buildings requires an integrated approach, where a team of experts work together to engineer an architectural solution that is functional, comfortable, energyefficient, and perhaps inspirational. Integrated façade systems (or any other part of the building) sometimes do not work as expected because of components substitutions during construction. Without measurement of system performance one can never be certain haw well a given system is working. This is particularly true of integrated façade systems; since relatively few have been installed and monitored to date; too little empirical knowledge about them is available to be universally useful. To fully understand how such a system is working, it is necessary to measure. Advanced Daylighting elements utilized are: 2-3-3-1 Daylighting Monitors. 2-3-3-2 Super windows. 2-3-3-3 Spectral glazing for better daylighting. 2-3-3-4 Angular selective solar control. 2-3-3-5 Optical daylighting system. 2-3-3-6 Dual light shelf design. 2-3-3-7 Exterior redirecting: 2-3-3-7-a- Exterior reflectors. 2-3-3-7-b- Anodlic mirrors. 2-3-3-7-c-Prism Panels. 2-3-3-7-d-Light shelves. 2-3-3-8Interior louver systems: 2-3-3-8-a- Prismatic Acrylic Louvers. 2-3-3-8-b-Curved Metallic Louvers. 2-3-3-8-c- Folded Metallic Louvers. 2-3-3-9Integrated in vertical double glazing: 2-3-3-9-a- Symmetrical metallic profiles. 2-3-3-9-b-Asymmetric metallic profiles. 2-3-3-9-c-Curved acrylic strips. 2-3-3-9-d-Prismatic acrylic panels. 2-3-3-9-e-Laser – cut acrylic panels. 2-3-3-10Integrated in horizontal double glazing : 2-3-3-10-a- Asymmetric metallic profiles. 2-3-3-10-b-Glass or acrylic capillaries. 2-3-3-10-c-Glass webbing. 2-3-3-11Light pipe , step index fiber.

2-3-3-1 Daylight Monitors: Monitors are roof structures that utilize vertical or steeply sloped glazing. This allows contribution of roof reflected light, and more direct exposure to winter sunlight.

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Incorporate daylighting monitors and skylights into enclosed spaces in order to maximize the amount of daylighting. Daylighting monitors control the amount of artificial light levels inside a building depending upon the amount of natural light penetrating the interior spaces [ Aboulnaga, 2003].

2-3-3-2 Super window: These are double or triple-paned windows filled with argon or krypton gas and containing a nearly invisible low-emissive coating. They are the most dramatic improvement in window technology. They offer R-values of 4.5 to almost 12. Super windows also block noise and protect interior finishes from ultraviolet damage. Though they cost more (15% - 50%) they save huge amounts of heating and cooling energy, resulting in immediate paybacks by allowing for the downsizing of air conditioning and heating systems in buildings. Heat Mirror TM is an example of a super window [ Aboulnaga, 2003].

2-3-3-3 Spectral Glazing for better Daylighting: Spectrally selective glazing is window glass that permits some portions of the solar spectrum to enter a building while blocking others. This high-performance glazing admits as much daylight as possible while preventing transmission of as much solar heat as possible. By controlling solar heat gains in summer, preventing loss of interior heat in the winter, and allowing occupants to reduce electric lighting use by making maximum use of daylight, spectrally selective glazing significantly reduces building energy consumption and peak demand. Because new spectrally Glazing can have a virtually clear appearance, they admit more daylight and permit much brighter, more open views to the outside while still providing much of the solar control of the dark, reflective energy-efficient glass of the past. They can also be combined with other absorbing and reflecting glazing to provide a whole range of sun control performance. Because of its solar heat transmission properties, spectrally selective glazing climates where solar heat gains in summer and interior heat loss in winter are both of concern. In other words, different variants on these glazing are appropriate for residential and commercial buildings throughout the United States. The energy efficiency of spectrally selective glazing means that architects who use it can incorporate more glazing area than was possible in the past within the limitations of codes and standards specifying minimum energy performance. When spectrally selective glazing is appropriately used, the capacity of the building's cooling system might also be downsized because of reduced peak loads (figure 2-27, 2-28 and 2-29) [ Aboulnaga, 2003].

Figure 2-27 Light-redirecting skylight, Berlin [source / Aboulnaga, 2003].

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Figure 2-28 Oracular between-pane louver system [source / Aboulnaga, 2003].

Figure 2-29 Solar Filters [source / Aboulnaga, 2003].

2-3-3-4 Angular Selective Solar Control: Angular selective facades provide solar control based on the sun's angle of incidence on the façade. The main technical objective is to block or reflect direct sun and solar heat gains during the summer, or during the majority of the cooling season for a given building type, but admit diffuse sky-light for Daylighting. Several engineered, fixed louver systems have been designed specifically to address this technical objective for the European Union (EU) climates and latitudes. For example, the Okasolar between- pane louver system consists of 2-cm-wide mirrored aluminum louvers with a unique geometrical profile. Direct sun is blocked and reflected out while diffuse sky-light is admitted from the sky. The optimum vertical angle of blockage occurs along the north-south axis at solar noon. Research to develop angular selective coatings on glass has proven to be challenging and has not yet resulted in a commercial product. This film coating techniques can to create microstructures that in principle, selectively reflect visible or solar radiation based on bi-directional, hemispherical angles of incidence. Energy and Daylighting performance of such structures has been evaluated by Sullivan et al. 1998. Interesting variations on this theme include between-pane louvers or blinds with a mirrored upper surface, to be used in the clerestory portion of the window wall, or exterior glass lamellas (louvers) where the upper surface is treated with a reflective coating. These systems fully or partially block direct sun and redirect sunlight to the interior ceiling plane. Conventional louvered or Venetian blind systems enable users or an automated control system to tailor the adjusted angle of blockage according to solar position, daylight availability, glare, or other criteria. Another variant includes between-pane acrylic prismatic panels that are either fixed or used as a

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system of exterior louvers to block direct sun and admit diffuse daylight. For vertical windows, the panels must be adjusted at least seasonally to block sun and to prevent color dispersion. Fixed systems can be used in roof applications [ Aboulnaga, 2003].

2-3-3-5 Optical Daylighting System: The design for the Corporate Express World Headquarters achieves exemplary energy efficiency through the use of advanced daylighting, lighting and envelope design. The design team integrated sustainable design strategies throughout the building. The daylighting system achieves maximum daylight harvesting and produces operative ambient light levels throughout the open office cubicles for nearly all occupied hours during the year under all sky conditions. Major Daylighting features include: state-of-theart optical daylighting system; increased floor-to-floor height; dedicated daylighting glazing; zoned daylight dimming; and low-e glazing tuned by orientation and location [ Aboulnaga, 2003].

2-3-3-6 A dual Light shelf Design: A dual light shelf design with separate high performance vision and daylight glazing, modeled by AEC and then installed around the entire perimeter of the three story building creates comfortable, daylight open office spaces. The buildings meets the City of Fort Collins Facility Services Green Building Criteria, a criteria based on the leadership in Energy and Environmental Design (LEED) Criteria, and incorporates water conservation, sustainable materials and energy efficient design features, to use 25 % less energy then the Fort Collins Energy Code minimum (figure 2-30) [ Aboulnaga, 2003].

Figure 2-30 A dual light shelf design, front Collins office building [source / Aboulnaga, 2003].

2-3-3-7 Exterior redirecting: The most effective way to bring daylight into a building (besides opening the roof) are reflecting elements in front of the facade.

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2-3-3-7-a- Exterior Reflectors… Exterior reflectors "see" a very big portion of the sky. For this reason they can transport more light into a building through the vertical façade than most systems following other principles.

Figure 2-31 Exterior Reflectorsb[source / Aboulnaga, 2003]. 2-3-3-7-b- Anodolic mirrors… The efficacy of reflectors can be significantly enhanced through a specifically curved shape. This type of curve is derived from research on non imaging optics, and requires custom design and construction.

Figure 2-32 Anidolic Mirrors [source / Aboulnaga, 2003]. 2-3-3-7-c- Prism Panels… Prism panels are primarily applied for solar protection, since they shield against a narrow angle of incident light. But some (mostly asymmetric) variations can also be used for daylight redirection. The normal vector of the panels should always correspond to the solar altitude.

Figure 2-33 Prism Panels [source / Aboulnaga, 2003]. 2-3-3-7-d- Light Shelves… Interior reflectors are usually designed as light shelves. The more reflective and specular the upper surface, the higher the efficacy.

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2-3-3-8 Interior Louver Systems: The traditional concept of interior louvers for solar protection has recently been enhanced with many fresh ideas. While exterior louvers generally are better in reducing the direct solar heat impact, interior systems don't attract nearly as much dirt. Because of this, they can be made with high gloss surface, which grantees very effective redirection properties [ Aboulnaga, 2003]. 2-3-3-8-a- Prismatic Acrylic Louvers… For the daylight expert, prismatic panels already count as "traditional ". A relatively new development is interior stackable louvers following the same principle. The system needs to precisely follow the solar height to provide good sun protection. 2-3-3-8-b- Curved Metallic Louvers… Turn the traditional removable louver system on its head and give it a high gloss surface. This is probably the daylight redirection system that is simplest to understand and handle. 2-3-3-8-c- Folded Metallic louvers… Play around with that metal band a little more and you get some additional functionality. This type of louver reflects incident light from high angles while it redirects lower angles. The system that is actually sold has a slightly different shape than the one shown here [ Aboulnaga, 2003].

Figure 2-34 Shows recent innovative louvers [source / Aboulnaga, 2003].

2-3-3-9 integrated in vertical Double Glazing: 2-3-3-9-a- Symmetrical Metallic Profiles Metallic profiles built into double glazing are quite traditional products by now. Symmetric systems have the advantage that a large portion of the incident light Is redirected to the interior ceiling. 2-3-3-9-b- Asymmetric Metallic Profiles Asymmetric profiles can reflect parts of the incident light, usually from

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high angles. This helps to avoid some of the heat impact in summer, while more light enters the room in winter.

2-3-3-9-c- Curved Acrylic Strips This technology is relatively new, and is very effective in redirecting direct as well as diffuse daylight. Care must be taken to keep interior luminances under control to avoid glare. 2-3-3-9-d- Prismatic Acrylic Panels… This is a very traditional method of sun protection. The surface normal of the element should be as close to the solar angle as possible for maximum effect. 2-3-3-9-e- Laser- cut Acrylic Panels… Some of those systems are actually manufactured without the use of a laser, but the name sticks well. In practice, the cavities are slightly curved to reduce color separation effects. This element type gives a fairly unobstructed vies, though this also allows some direct solar impact [ Aboulnaga, 2003].

Figure 2-35 Shows recent innovative louvers [source / Aboulnaga, 2003].

2-3-3-10 Integrated in Horizontal Double Glazing: What works in the façade should be fair enough for skylights. However, the task here is normally rather than solar protection instead of daylight redirection.

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2-3-3-10-a- Asymmetric Metallic Louvers… As in the vertical variation, integrated asymmetric louvers can keep out incident light from a certain range of angles. Light from other, accepted, directions can enter the room and is partly redirected. 2-3-3-10-b- Glass or Acrylic Capillaries… In other contexts, this technology is known as "transparent thermal insulation". The effect on light is a relatively diffuse output distribution, with a peak in the surface normal [ Aboulnaga, 2003]. 2-3-3-10-c- Glass Webbing… Glass webbing is sometimes combined with the system above, and provides for a complete diffuse transmission. Depending on the thickness of the webbing, the transmission factor of the system can be controlled in a fine grained manner.

Figure 2-36 Shows recent innovative louver [source / Aboulnaga, 2003].

2-3-3-11 Light Pipe, Step Index Fiber: In light pipes and step index fibers, rays enter a tube (being either solid or hollow) and reflect from the walls in an indeterminate number of times until they emerge. The end surfaces may have any form (spherical, a spherical, Fresnel, etc.) and may also be arbitrarily tilted. Light pipes are formed by extruded surfaces and are handled by the sequential surface model. Circular or rectangular cross sections are supported. All forms may be tapered. Rectangular light pipes can also be sheared. Violation of total internal reflection (TIR) in solid pipes is taken into account [ Aboulnaga, 2003].

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Figure 2-37 Light pipes with step index fiber [source / Aboulnaga, 2003].

2-3-3-12 Examples for Innovative Daylighting Systems: In this part we talk about examples for innovative daylighting systems, in this examples we can see building use one or more from innovative daylighting systems in the same time to reduce effect of electricity lighting but when we reduce this effect we cannot reduce the heat with daylight so a good ventilation is used to reduce the heat effect of daylight. So we explain in this part how we can use a good ventilation to reduce the heat effect of daylight. 2-3-3-12-a- BRE Building in England, UK The project is low-energy office building for 100 people with operable shading systems on the south building façade, stack ventilation and cross ventilation. A key feature of this building is the integration between Daylighing strategies and natural ventilation. The floor plan (shaded in yellow in the picture to the left) is divided into open-plan and cellular offices allowing cross ventilation in the open plan arrangement while the 4.5meter-deep cellular offices are located on the north side with single-sided natural ventilation. A shallow open-office plan is coupled to a highly glazed façade. A wave-form ceiling structure is used. At the high point of the wave, a clerestory window allows daylight to effectively penetrate the space. A duct providing space conditioning and ventilation was placed within a hollow core at the low point of the wave-form structure. For shading, translucent motorized external glass louvers (Colt International) are controlled by the building management system and can be overridden by the occupants. The glass louvers can be rotated to diffuse direct solar or to a horizontal position for view. The exterior of the stacks are glazed with etched glass blocks, allowing daylight admission. Low-resistance propeller fans were mounted at the top-floor level, to provide minimum ventilation and to flush internal heat gains during the night [ Aboulnaga, 2003].

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Figure 2-38 The BRE Building [source / Aboulnaga, 2003].

Figure 2-39 Cross section through the glazed façade (left) and the ventilation stack (right) [source / Aboulnaga, 2003].

2-3-3-12-b- The Debis Headquarters The debis Headquarters in Berlin, Germany by Architect Renzo Piano Building Workshop and Christoph Kohlbecker was built in 1997 with daylighting system as double-skin façade. The project is a double-skin façade building built in Berlin by Renzo Piano Building Workshop and Christoph Kohlbecker.


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The project is a 21- storey high-rise office tower with a double-skin façade. The double-skin façade is divided into storey-high cavities. The exterior skin consists of automated, pivoting, 12-mm thick laminated glass louvers. Minimal air exchange occurs through these louvers when closed. The interior skin consists of two double-panes, bottom-hung, operable windows. The upper window is electrically operated. On the interior of the internal windows are Venetian blinds. Walkway grills occur at every floor within the 70-cm wide interstitial space and are covered with glass to prevent vertical smoke spread between floors. During the summer, the exterior glass louvers are titled to allow for outside air exchange. The users can open the interior windows for natural ventilation. Night-time cooling of the building's thermal mass is automated. During the winter, the exterior louvers are closed. The user can open the internal windows to admit to the warm air on sufficiently sunny days [ Aboulnaga, 2003].

2-3-3-12-c- Deutscher Ring Verwaltungsgebäude This project is located in Humburg, Germany designed by Architects BDA, Bassewitz,Patschan, Hupertz und Limborck in 1996. On the south façade, an 80-cm deep by 24.10m four-storey high double façade provides thermal and acoustic protection. The exterior skin is point-fixed, toughened, solar control, single-pane glazing. The interior skin consists of low-E coated, double- glazed, punched windows and spandrels. Blinds are positioned interior to the internal glass windows. There are staggered exterior openings at the base of the curtain wall (not clear whether at each floor or simply at base of the fourstorey facade). The top of the four-storey façade has a rainproof opening with overlapping glass panes that allow air exchange. For cooling, solar radiation absorbed by the exterior glazing layer is vented or extracted by natural convention through the top opening at the fourth floor. Some of the interior windows are operable to allow for cleaning within the interstitial space. Walkway grills occur at every floor within this interstitial space.

Figure 2-41 Cross section through the glazed façade (left) and the ventilation stack (right). [source / Aboulnaga, 2003].

2-3-3-12-d- Düsseldorf Stadttor (City Gate) This project was completed in 1997, Düsseldorf, Germany and designed by Petzinka, Pink & Partners. It is a 16-storey tower with a 56-m high atrium in the center. Each tower has a corridor double-skin façade with a single- storey interstitial space that 90-140 cm deep and 20-m long. The interior façade has double-pane, low-E glazed doors that pivot every second bay. The exterior façade is 12-mm fixed safety glass. Highreflectance Venetian blinds are located in the interstitial space. Mechanical ventilation is provided during peak summer and winter hours. Chilled ceilings provide radiant cooling. The building can be naturally ventilated for 60% of the year [ Aboulnaga, 2003].

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2-3-3-12-e- Eurotheum Building The project was completed in 1999 in Frankfurt, Germany and designed by Novotny Mähner & Associates is a 100-m high residential and office mixed-use building and has a square 28 by 28m plan. Only part of the building is designed with double-skin façade, which provides natural ventilation for most of the year. Office space occupies the lower part of the Eurotheum Tower while the top seven floors are used for residential purposes. The façade grid is 1350 mm wide and 3350mm tall. Each unit, which is prefabricated off-site, consists of a 6-grid span, one-storey tall. The internal skin consists of thermally-broken aluminum frames and double-pane, manually-operated, tilt-and-turn windows. Power-operated blinds are located in the 34-cm-wide air cavity corridor. The external skin consists of single-pane, fixed glazing. Fresh air is supplied through 75-mm diameter holes in the vertical metal fins on each side of the glazing unit.


2-3-3-12-f- The GSW Headquarters The project completed in 1999 in Berlin, Germany and designed by Sauerbruch Hutton Architects, is a 22-storey high, 11-m wide office building with cross ventilation and a double-skin thermal flue on the west-facing façade. The east façade consists of automatically and manually-operated triple-glazed windows with between-pane blinds. Louvered metal panels also occur on the east façade to admit fresh air independently from the windows. The west façade consists of a double-skin façade with interior double pane windows that are operated both manually and automatically and a sealed 10-mm exterior glazing layer. The interstitial space is 0.9-m wide. Wide, vertical, perforated aluminum

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louvers located in this interstitial space are also automatically deployed and manually adjustable. The louvers can be fully extended to shade the entire west façade.

Figure 2-44 Exterior views of the vertical louvers on the west façade. [source / Aboulnaga, 2003].

2-3-3-12-g- Office at Halenseestrabe This project was completed 1996 in Berlin by Hilde Léon, Konrad Wohlhage is a ten-storey building. The top west-facing seven stories of this are designed with a doubleskin façade. Façade on other orientations are congenial single-layer windows. The doubleskin façade reduces noise from the adjacent highway towards the west. The 12-mm singlepane external skin of this double-skin façade is completely sealed while the internal skin consists of sliding double-pane glass doors. A blind was installed within the 85-cm wide, 1 storey high interstitial space. During the summer, the blinds can be used to block solar radiation while the interstitial space in mechanically ventilated. At night, internal heat gains are removed with mechanical ventilation. During the winter, solar gains pre-warm the air in the interstitial space [ Aboulnaga, 2003].

Figure 2-45 Exterior views of the vertical louvers on the west façade [source / Aboulnaga, 2003].

2-3-3-12-h- Inland Revenue Centre This is the leading project in Nottingham, UK is completed in 1995 and designed by Micheal Hopkins & Partners. It is a low-rise L-shape building with corner staircase towers. The main strategies are the maximization of daylight and engineered natural ventilation. Lighting Strategies: • •

Integrated Lightshelf shades space in the perimeter zone and reflects light into the space. Light-colored ceiling improves reflectance of daylight high ceiling (3.2 m) helps with thermal stratification. Exposed concrete soffit acts as thermal mass, absorbing daytime heat gain.

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Triple glazing with between-pane adjustable blinds. Balcony and shading devices. External brick piers provide lateral solar shading.

a) General views.

b) Section showing the façade daylighting

strategies. Figure 2-46 Daylighting Inland Revenue Center in Nottingham, UK [source / Aboulnaga, 2003].

2-3-3-12-i- Islip Federal Building and Courthouse The project in Islip, New York was completed in 2000 and designed by Richard Meier is a 11-storey U.S. courthouse with horizontal louvers on the south façade. Horizontal exterior fixed louvers span across the entire south façade. The louvers are made of perforated metal which blocks direct solar radiation yet allows a small percentage of daylight to be admitted to the interior. The louvers are scaled to block unwanted solar radiation in the summer months and to allow its direct penetration during the winter months. The main corridor runs along the length of the south façade, creating a thermal buffer to the interior courtrooms. The area shaded in green is the circulation space. The red shaded areas are the horizontal louvers on the façade system [ Aboulnaga, 2003].

2-3-3-12-j- RWE AG Headquarters This project in Essen, Germany was completed by 1997 and designed by Ingenhoven Overdiek ands Partners, is a 28-storey high-rise tower. The design of the RWE façade system was influenced by the client's desire for optimum use of daylight, natural ventilation, and solar protection. All these demands resulted in a transparent interactive façade system which encompasses the entire building. The exterior layer of the double- skin façade is 10-mm extra-white glass. The interior layer consists of full height, double-pane glass doors that can be opened 13.5 cm wide by the occupants (and wider for maintenance). The 50-cm wide interstitial space is one-storey (3.59m) high and module (1.97 m) wide. Retractable Venetian blinds are positioned just outside the face of the sliding glass doors within the interstitial space. An anti-glass screen is positioned on the interior. Daylight, direct solar and glare can be controlled with blinds and an interior antiglare screen [ Aboulnaga, 2003].

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2-3-3-12-k- Center for the Clinical Science Research, Stanford University The project, in Palo Alto, California was completed in 2000 and designed by Norman Foster is a low-rise research facility which integrated solar shading system and natural ventilation. The façade system at the Center for the Clinical Science Research at Stanford University was designed in response to the moderate Palo Alto climate. To protect the building from sun, a series of large overhangs was placed to block direct sun on the south façade. The shading devices are made of a semi-opaque material, which allows a small portion of daylight to enter the interior space. The Center takes full advantage of daylight by dividing the building mass into two separate buildings, separated by a linear atrium, which runs east-west. A grill-like shading system was installed on the atrium roof to filter strong California sunlight [ Aboulnaga, 2003].

a) Detail of the shading device on the south facade.

b) Exterior view of the south façade from the adjacent parking lot.

a) North façade b) linear atrium with grill-like shading system c) Atrium façade with Operable windows. Figure 2-47 Daylighting System in Center for the Clinical Science Research.

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2-3-3-12-l- CNA-SUVA Building The project in Basel, Switzerland completed in 1993 and designed by Herzog and DeMeuron, is a renovated low-rise office building in Switzerland by the addition of exterior layer of prismatic panels. the double-skin façade reduces heat losses in the winter and heat gain in the summer through optical control of sunlight. Within one floor height, the double-skin façade can be divided into three sections. The upper section is made of insulating glass with integrated prismatic panels which automatically adjusts itself as a function of the altitude of the sun. This panel has two functions: reflecting sunlight toward the outside and admitting daylight into the interior space. The vision window is made of clear insulating glass and is manually operated by the occupant during the daytime. The lower level window is automatically controlled to stay closed when solar and thermal insulation is desired [ Aboulnaga, 2003].

Figure 2-48 The Prismatic Panel reflects light to the desired angle. [source / Aboulnaga, 2003].

2-3-3-12-m- Victoria Life Insurance Buildings This project in Cologne, Germany was built in 1996 and design by Valentyn & Tillmann , Köln is a made of external skin which consists of 15 mm laminated solar control glazing ; the internal skin consists of solar control fixed glazing. Aluminum 50mm-wide louvers are integrated into the 80 cm-wide corridors, which are equipped with walkway grills for access. The main advantage of the double-skin façade system is the improvement in the thermal comfort. In winter, the air vents in the corridor can be closed, letting the air warm up, which reduces the difference between inside and outside temperatures and consequently reduces heat loss. Warm air increases the surface temperature of the glass, which makes the area near the windows more thermally comfortable. For this building, the large glass area provides daylight access, which enhances motivation, performance and productivity at work [ Aboulnaga, 2003].

Figure 2-49 Double-skin façade made of external skin which consists of 15 mm laminated solar control glazing, the internal skin consists of solar control fixed glazing.

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2-3-3-12-n- Recent Built Project Simulated with Ray front The state of the art software for a straightforward lighting design studies, where the visualization was just used as plausibility, while others are modeled in more detail and rendered more thoroughly. This is usually the case with projects where the client explicitly demanded photorealistic images.

Figure 2-50 HUK Coburg Office entry hall, Coburg,Germany [source / Aboulnaga, 2003].

2-3-4 Conclusion… The review of the state of the art of advanced daylighting systems illustrated a wide varieties in the techniques used. It became clear that recently with the emerged Spectral glazing large area of faced in hot climate become less problematic. Also, the innovative laser-cut panels allowed light to fall directly into the space and heat is rejected. In the period between 1995-2002 there were so many daylighting systems that contributed to the improvement of lighting level and its distribution. Building design with the aid of advanced daylighting system can make the interior space more comfortable, happier, pleasing and also productive. This will have an impact on the building operating cost and eventually also reduce the energy consumptions. With the recent green building rating issued by the American Green Building Council (LEED) it is necessary that architects should utilize these systems to reach the rating level as far daylighting criterion is concerned specially in the developing world. Good ventilation is used to reduce the heat effect of daylight [The Researcher].

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Chapter 3:

3-1 Daylighting Calculation. 3-1-1 Daylight prediction techniques. 3-1-1-1 Calculation Methods. 3-1-1-2 Graphical Methods. 3-1-1-3 Simulation Methods. 3-1-2 Conclusions.

3-2 Determination of the ways to deal with daylight. 3-2-1 Showing the problem and its reason. 3-2-2 Examples from Egypt. 3-2-3 Examples from Europe.

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3 -1 DAYLIGHTENING CALCULATION 3-1-1 Daylight prediction techniques. Introduction... Recently in the last century the calculation method has been developed to the daylight factor. In the past it was dependent on the tables and equations which used to know the required ratios to be achieved in the space, also the lighting reflections on the different surfaces, opening size, and other influential elements on the daylight factor. Although this operation requires precision and much attention, its error rate “factor” was in a very high percentage. This is because of the large and complex mathematical operations significantly, which increase the error percentage for the person who uses such operations. By time, the mathematical operations and equations which used ”aimed” to reach the daylight factor value have been represented by flow charts and counter maps. This facilitates the way for the designers and architects to discover the darkest places in the space to design its openings. Although that, this drawings contain some errors, this because of the many inaccurate readings. Also its non-successive “non-sequential” in short periods... Accordingly this doesn’t result into more coordinates so we can connect between them to reach to more accurate and clear curve but it is surely less than the calculation which had a higher error rate “factor”. With the rapid evolution of the technology and the achieved breakthrough in the simulation programs” the new inventions in the simulations programs” , many programs has been invented to help the designer in his designs of the buildings internal spaces, also the openings designs in these spaces. These programs are distinguished from the others in the two previous methods because of the existence of important factors which are the speed and the accuracy. These programs are characterized with their speed in the daylight factor calculations, Also their ability to obtain highly accurate flow chart in a recordable time. This is helpful for the designer to achieve his work in a short time. Through this introduction we can conclude that the calculation method of the daylight factor consist of three phases “stages” which are the calculation method, the graphical method, and the simulation methods which is considered a combination of the two previous methods but with less error rate and high speed. The following programs are considered examples of the simulations programs: Ecotect, Daysim, Radiance, & Skyvision”. The following will explain each method separately, and its pros, & cons “its advantages, & disadvantages” [The Researcher]. The most obvious and important aspect of daylighting calculation and design is the variable nature of the source. The results are tied to a prediction of external conditions that vary with the time of the day, the day of the year, and with the weather. In some countries sufficient daylighting is seldom available during the whole of the daylighting working hours throughout the year. It is necessary to decide the percentage of working hours for which adequate lighting is to be provided. By statistical evaluation of long term illumination records, for a given location an outdoor illumination level can be established which is exceeded in 90% or 85% of the time of daylight hours. This is taken as the "design sky" illumination value for the particular location. As mentioned before, daylight

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illumination in an interior can be expressed either in absolute terms or as a percentage known as the daylight factor. Daylight design considers two basic stable conditions. a. The completely overcast sky which may be considered either of uniform luminance, or having a given non-uniform luminance distribution, such as the CIE sky. With such a sky, it is practical to think of light admitted as a percentage of the total light available from the hemisphere of the sky. Orientation and location can be ignored. The design is based on light reaching the window from two sources, the overcast sky and the exterior surface's contribution of reflected light. b. The clear blue sky, with or without sunlight, for which a luminance distribution for the sky may be obtained from knowledge of the sun's position and the relevant scattering constants for the atmosphere. The luminance of the ground and vertical surfaces may be found from knowledge of the luminance from the sun, sky and the reflecting properties of these surfaces. With clear sky conditions it is possible to work with actual values of illumination that will vary considerably with orientation, location and season. The design is based on light reaching the window from three sources, direct sun, clear sky and reflected light from ground or exterior surfaces. In case of the clear sky without sunlight, the direct sun's contribution is omitted [The Researcher].

Fig 3.1 Diagram of daylight calculation classification [source / The Researcher].

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B ِ ut there is another way for daylight calculation classification this way is: a. Single – stage methods: In which the total daylight, that is direct day-light, externally and internally reflected light, is calculated by means of one operation based on a number of empirical assumptions and compromises, for example the B.R.S. Daylight Factor Slide Rule. b. Stage-by-stage methods: In which each individual components of the total daylight illumination reaching the reference point, that is the direct light from the sun and the sky, the light reflected from external surfaces and the internally reflected surfaces, are all calculated independently and summed to give the total daylight factor at the reference point. The Stage-by-Stage methods are classified according to the following: Tabular methods. Diagrammatic methods. Models methods. Mathematical methods. The B.R.S daylight factor slide rule has been classified according to the calculation method and there is another classification according to the graphical method. This is because it depends on both categories to obtain "find" the daylight factor. The contours drawings can be represented from the estimated values in the spreadsheets and the results of the mathematical equations. Also for the dark places, and the lighting degradation directions "trends" in the places & according to the windows & openings places, and the lighting depth in the space. This is helpful for the designer to choose and distribute the electrical lighting places in the space to achieve the required rate of lighting according to its purpose [Hopkinson, 1990]. The B.R.S. Daylight Factor Slide Rule… It is a device that enables the daylight factor in a side-lit room to be evaluated in one step, for a number of points in the room, provided the height of the ceiling, the distance of the point on the center line from the window, the reflectance's of the walls, floor, ceiling and the size of the window are all known. Usually in most cases of daylighting calculations, the room is divided out into a regular grid, the closeness of which depends on the desired precision of the calculations. Calculations are made for each point separately, then contours of equal daylight factors or of equal illumination are plotted. There are approximately elliptical in shape (fig 3-2). These contours can be used as a reference in any study of the uses to which the room is to be put. For example, if it is to be used as a classroom, the minimum daylight factor as recommended from table (3-1) is 2%. It would be necessary to lay a tracing of the daylight contours over the plan of the room on which the teaching area is delineated. If the 2% contour included all the desks, then the design is successful, if it does not, some alternation has to be made [Hopkinson, 1990].

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Fig 3.2 example of daylight factor contours on horizontal working plan [source / Dr.Nagwa zaki, PHD thesis]

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Building type

Recommended Daylight factor %

Chapter 3

Qualifications / Recommendations

Dwellings

kitchen

2

Living room

1

Bed room

0.5

Over at least 50% of floor area ( minimum of 4.5 sq.m) Over at least 50% of floor area ( minimum of 7.0 sq.m) Over at least 50% of floor area ( minimum of 5.5 sq.m)

Schools

2

Over all teaching areas and kitchen.

Hospitals

1

Over all ward area.

General

1

With lighting penetration of 3.75m.

Drawing offices

6

On drawing boards.

2

Over remainder of working area.

Typing and computing

4

Over whole working area.

Laboratories

6

General recommendation.

Factories

5

Maximum on walls or screen.

Art galleries

6

General over all area.

Churches

1

Public building

1

Depending up on function, the recommendation may exceed 1% is generally desirable in most public building.

Offices

Adapet from , J. Longmore , BRS Protractors ( London: Her Majesty`s Stationery Office 1986) , p.21

Table 3.1 Recommended levels of general or minimum daylight factor in building.

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3-1-1-1- Calculation Methods This method depends mainly on two elements to calculate the daylight factor which are the spread sheets & the mathematical equations. The spread sheet can be used to obtain the required value of daylight factor to be achieved in the design of space according to the required purpose. It also used to obtain the lighting reflections values on the different materials. So these values can be used in the mathematical equations to find the daylight factor value in the space and compare it with the estimated values in the spread sheet. The main equation to find daylight factor is: DF = SC + ERC + IRC The sky component (SC) . The external reflectance component (ERC) . The internal reflectance component (IRC) . 3-1-1-1-a- Tabular methods There are several published tabulations which enable the computation of daylight factor or the illumination to be obtained. Of these the most useful are: 1- The N.P.L. Graded Daylight Tables: which enables the sky component to be obtained for conditions of uniform sky brightness. 2- Rivero's Tables: Which are most versatile and permit the sky component to be determined for conditions of uniform and CIE Sky. 3- B.R.S. Simplified Daylight Factor Tables: Which aim at a lower order of accuracy than other tabulators, but greater simplicity in use. They give the sky component under conditions of both uniform and CIE sky and they also give the internal reflected component. 4- The Fenestra Method: which gives actual level of illumination at three single points under a uniform sky and reflected sunlight. it is a collection of simple tables valid for room lengths and widths not exceeding 10.0 m and ceiling heights between 2.4 and 3.6m [Dr.Nagwa zaki, PHD thesis]. 3-1-1-1-b- Mathematical methods Numerous mathematical approaches have been developed for calculating the illumination levels inside a room. Calculation can provide fast and accurate assessment of these levels. Present procedures can be divided into two categories. 1. Hand-Calculations Procedures: They are either longhand or simple. The later often make simplifications and assumptions that may reduce flexibility and accuracy.

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2. IES Daylight Procedure: Which is a longhand method for calculating illumination levels in a room. It is based on determining the quantity of illumination coming to the window surface, whether from clear or overcast sky and then calculation the quantity of daylight in the interior. 3. Fruhling's Coefficient of utilization Method: Which gives average and minimum daylight factor under overcast sky conditions, it is based on readings taken in a variety of existing rooms and gives only approximate result. 4. B.R.S. Interreflection Formula: which gives the internally reflected components at back and mid-depth of side-lit rooms under CIE sky. It is of greater precision that other methods and generally used with the Waldram Diagram. 5. The Lumen Method: Which gives actual levels of illumination expressed in terms of maximum, minimum and average values of daylight, on the horizontal working plane. It is based on the coefficient of utilization concept and gives the illumination under uniform, CIE and clear sky conditions. 6. Computerized procedures: Computerized design techniques have been developed. They require the preparation of detailed input-data access to computers, or time-sharing computer facilities. But, because of the speed of the computer, a more complete and accurate profile of daylighting contribution can be obtained. 7. A Daylighting Model for Building Energy Simulation: Which is a system of FORTRAN subroutines designed for inclusion into larger building energy simulation programs, one of them predicts interior daylight illumination at various points within a room due to any number of windows. The program could be executed on a micro computer provided it has a FORTRAN compiler. 8. Computer Program for the Calculation of Daylight level in a Room: Which calculates the daylight caused by direct incident light, reflected light from opposite buildings and ground, and interreflected light from room's elements, on arbitrary points in the room. 9. Daylighting Computation: A large computer package, which makes use of accurate analytical methods. 10. Quicklite . I : A procedure which calculates the illumination at any point within a room under CIE and clear sky, using a programmable hand calculator. 11. Quicklite 1.0 for Daylighting on Obstructed Sites: A similar procedure like the previous one, but taking into account the presence of obstructions outside the window [Dr.Nagwa zaki, PHD thesis].

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3-1-1-2 Graphical Methods 3-1-1-2-a- Diagrammatic methods There exist a number of diagrammatic methods which enables the daylight factors to be evaluated, among them are: 1- B.R.S. Daylight Protractors: Which are devised primarily to simplify the calculation of the sky component to enable daylight measurements to be made from architect's drawings, In this respect they are not design methods but merely an aid to design (fig.3.3). 2- Half Cube Method: This gives the sky component and the externally reflected component under CIE sky and uniform sky. It is particularly useful when the external obstructions are complex. 3- The Waldram Diagram: This gives the sky component and the externally reflected component under CIE sky and uniform sky. It is particularly useful when the external obstructions are complex (fig.3.4) [Dr.Nagwa zaki, PHD thesis].

Fig 3.3 BER SC protractor number 2 for a vertical glazing under the CIE overcast sky [source / L.Robbins,1985].

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Fig 3.4 Simplified Waldram diagram for glazed apertures under the CIE overcast sky [source / L.Robbins,1985].

3-1-1-3 Simulation Methods 3-1-1-3-a- Modeling methods A number of daylight simulation methods, have been developed over the past 50 years, making use of simulated or artificial skies and building models. Simulation techniques have the advantage of allowing for unique buildings shapes and room’s configurations. In the last 50 years, the method of the daylight simulation has been developed to calculate the daylight factor. These programs use the different conditions of the sky which it are already entered in the program according to the different locations, longitudes, latitudes which specify the estimated location where the model will be built in it .Based on this information, in this part, we will preview quickly three programs and how they operate or function. Also the input & output format, and the result that we can get when we use these programs [Dr.Nagwa zaki, PHD thesis]. We have chosen this program based on the recommendation of the Canadian supreme institution of the daylight as it recommended those programs as the best three programs in 2006. We will review and talk about the following programs (Ecotect, Daysim, Radiance). 1- ECOTECT Interface ECOTECT v5.20 is the most comprehensive and innovative building analysis software in the market today. It features a designer-friendly 3D modeling interface fully integrated with a wide range of performance analysis and simulation functions. What really sets ECOTECT apart is the visual nature of calculation feedback and its support for very early stage conceptual design as well as final design validation. Designers can start generating vital performance-related design information before the building form has even

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been developed. You can start with a detailed climatic analysis to calculate the potential effectiveness of various passive design techniques or to optimize the use of available solar, light and wind resources. You can then move on to test these ideas on some simple sketch models before gradually developing up the final design.

Fig 3.5 Ecotect Interface [source / http://www.Ecotect.com] As ECOTECT deals with many different aspects of building performance, it needs a wide range of data to describe the building. To reduce the burden on the designer, ECOTECT uses a unique system of progressive data input. Initially only simple geometric details are needed. As the design model is refined and more accurate or detailed feedback is required, the user makes more choices and enters more data as it becomes important. This means that you can be analyzing sun penetration, shading options and available light after only a few mouse clicks [http://www.Ecotect.com]. You can use ECOTECT to do the following: • • • • • • • • • •

Display and animate complex shadows and reflections. Generate interactive sun-path diagrams for instant overshadowing analysis. Calculate the incident solar radiation on any surface and its percentage shading. Work out daylight factors and artificial lighting levels either spatially or at any point. Calculate monthly heat loads and hourly temperature graphs for any zone. Generate full schedules of material costs and environmental impact. Trace the paths of acoustic particles and rays within any enclosures of any shape. Spray sound particles around an enclosure and watch the rate of decay. Quickly calculate statistical and raytraced reverberation times in any space. Export to VRML for interactive visualisation and presentation to clients.

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Export to the RADIANCE Lighting Program for physically accurate lighting analysis. Read and write a wide range of CAD and analysis file formats [http://www.Ecotect.com]. 2- Daysim Interface

Daysim is a daylighting analysis software that uses the Radiance algorithms to efficiently calculate annual indoor illuminance/luminances profiles based on a weather climate file. These profiles can further be coupled with a stochastic user behavior model to predict daylight performance indicators such as annual light exposure, daylight autonomy, and lighting energy use for different lighting and shading control strategies. The user behavior model mimics how building occupants interact with manual controls and is based on field study data. Radiance and Daysim are complementary and use the same input file format [http://www.radiance-online.org].

Fig 3.6 Daysim Interface [source / http://www.radiance-online.org]. Whenever you start a daylighting analysis in the Daysim ANALYSIS menu, Daysim automatically generates an internal gains file (*.intgain.cvs) which is stored in your “res” subdirectory. The file contains detailed annual simulation results in one-hour time steps. Please note that the file contains the individual internal gains in the investigated zone for the last user type investigated. This means that if you use a “mix of both” for their blind or lighting control, the sum of all hourly electric lighting uses given in the *intgain.cvs file might not correspond to the annual electric lighting use given in the Daysim simulation report, as the results will be a mean of energy uses for different users.

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3- Radiance Interface Advanced lighting simulation and rendering package; calculates spectral radiance values (illuminance & color) and spectral irradiance (illuminance & color) for interior and exterior spaces considering electric lighting , daylight and interreflection. Used by architects and designers to predict illumination, visual quality and appearance of design spaces. Used by researchers to evaluate new lighting and daylighting technologies and study visual comfort and similar quantities related to the visual environment. Input data like geometry and materials of design space, including luminary’s photometry and surface reflectance characteristics. Translators are available for DXF, Architrion and IESNA standard luminary’s files. Additional translators have been written by third parties for ArchiCAD and others. A third-party (shareware) CAD program, Vision 3d, can prepare Radiance input directly [http://groups.google.com/group/daysim].

Fig 3.7 Radiance Interface [source / http://groups.google.com/group/daysim]. Output data like luminance and luminance values, plots and controls, visual comfort levels, photograph-quality images and video animations.

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Table 3.2 comparative analysis for different daylight prediction techniques [The Researcher]. Points of criticism

Calculation methods

Diagrammatic methods

Speed in mathematical operations

Complicated boring mathematical operations & require longtime & expected errors (inaccuracy)

Representing the values in flow charts require Taking short time long time, accuracy & only in data entry. high concentration.

Accuracy in mathematical operations

How much the result is helpful to the designer in his design?

Possibility to application of this methods in Egypt climate.

Flexibility in changing the inputs data.

Require high concentration & accuracy. Any error will lead to recalculating over & again. The mathematical operations require more than one point to be completed leading to high error rate.

The results showed only in a numerical form & for the experimented place not for the remaining space.

Representing by flow charts show the lighting forms in this area which it is not accurate & difficult.

Not possible according to the unclear sky & climate like Alexandria.

Not available.

Simulation methods

The used programs are highly accurate & quickly calculating more than one point at the same time leading to accurate results & less error rate unlike the other two methods. The result can be represented in numerical &chart form. Combining the other two methods resulting in high quality photography of the expected position of each building not only for each space. Any climate can be used or entered according to the longitudes & latitudes which is available for free in the internet.

Easily available.

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3-1-2- Conclusions From the classification and review of the previous prediction techniques for daylighting design, one can deduce the following: 1. The previous comparative table showing the best method to calculate the daylight factor is the third method which is “ the simulation method “ characterized with it’s high speed & accuracy in the mathematical operations which it could be used to be applied on more than one point at the same time . Also the results such as the flow charts & photography which are totally helpful & clear for the designer through providing a clear vision of the expected position after the design which is not available in the other two methods. 2. The simulation method characterized by it’s flexibility in changing the inputs data and recalculation again & over which represent a signification problem for the other two according to the associated or a complained boredom & fatigue of such complicated operations. 3. Most of the techniques listed under tabular, diagrammatic, and mathematical hand calculations are for conditions of CIE and uniform skies, except for the IES Procedure and the Lumen Method, which give the illumination under both clear and overcast skies. From the metrological monthly weather data concerning the city of the Alexandria for a period extending from January 1973 to December 1981, one could judge that for the majority of the year the city witnesses a clear blue sky. This is the case with a coastal city, so if we compare it with other dryer cities in Egypt, it becomes obvious that the condition here in our country, is that of the clear blue sky, where the illumination varies considerably with orientation. Hence the majority of the techniques become invalid when designing for the daylight in our country. 4. Regarding the computerized processes, they are not available for every one and as mentioned before they require the preparation of detailed input data. Nevertheless they are the best procedures available for daylight calculations due to their accuracy and speed. 5. The programmable hand calculator program is very simple to use but it has its shortcomings. First it does not count for external obstructions which are very important since they affect the quantity of daylight inside a room. One could say that this was covered by the Quicklite 1.0 for obstructed sites. Second it gives the illumination at a point under a certain time and date and so the procedure has to be repeated often to give a good judgment as to the performance of the window throughout the year. In other words the calculations have to be repeated, for example, fifteen times to cover different altitudes of the sun, at least for 5hours/day/3seasons (spring and autumn seasons are identical). If the design failed to fulfill the requirements it would be repeated again. Therefore such a procedure using the programmable hand calculator can take a whole day of work just to reach a good design for one single room in a building [The Researcher].

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3-2 Determination of the ways to deal with daylight. 3-2-1 Showing the problem and its reason This subject is important because of the continued problem facing the architecture in how to get use of the openings places which directly affect lighting the internal space. It also has a great influence or impact on using the space which lead to many problems such as much lighting into the space causing the annoyed glare for the user. How to study the daylight, its relation to the building and the chosen space, entering it into the design process from the outset and at any stage are important factors creating a need to talk about this point, show the modern and developed techniques that carry out the simulation process and help the designer to determine the expected position as the new trends in the modern architecture is to get the maximum use of the natural components and resources and to reduce the use of electricity as much as possible [The Researcher].

3-2-2 Example in Egypt In this part we will talk about one example of Egyptian architecture projects which have AGA KHAN Award of architecture (1980) Project name: Ramses Wissa Wassef Art Center. Architect : Ramses Wissa Wassef. Place : Giza – Cairo – Egypt ( 1974).

Fig 3.8 Ground floor [source / http://www.greatbuildings.com].

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Fig 3.9 Elevation &Section Diagram [source / http://www.greatbuildings.com].

Fig 3.10 Interior picture Explain how used daylight to focus on the element [source / http://www.greatbuildings.com].

Fig 3.11 Interior picture for main hall [source / http://www.greatbuildings.com].

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The judgments committee have recommend the price to this project for its beauty, great values of its goals, social impact for its activity and the great architectural solutions which use the daylight in focusing on element placed on Art Center which stimulates the design and increase workable efficiency for the building.

3-2-3 Example from Europe 3-2-3-1 First example in this part is Project name: Kennydale Elementary school. Architect : Mc Granahan Architects. Place : Renton,Washington. (2004)

Fig 3.12 Master plans&Elevations [source / http://www.daylightinglab.com].

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Daylighting for buildings begins with a critical understanding of the patterns of sun movement and overcast sky dome behavior. Here in Seattle the sun reaches its highest point on June 21st at 68 degrees off the horizon (facing due south). While on December 21st, the sun only reaches 18 degrees off the horizon. September and March 21st split the difference with the sun cresting at 43 degrees. These measurements inform design choices as they apply to clear sky days, but the sheer number of overcast days here in the Northwest requires that we examine how light behaves in the overcast sky dome. The overcast sky dome is directionless meaning that orientation to north, south or otherwise is insignificant. What is important about the overcast sky understands that at the zenith (directly above) is three times brighter than the horizon. This implies that on overcast days horizontal skylights receive three times the illumination of vertical windows. [http://www.daylightinglab.com].

Fig 3.13 Sun movement and overcast sky dome behavior [source / http://www.daylightinglab.com]. Minimize East & West Glazing ... Ideally, planning for daylight begins at the site scale by orienting the building to the sun’s movement. Sun conditions on the north and south facades are much easier to control due to fairly regular sun angles (and the absence of direct sun). Conversely, blocking east and west sun means blocking view and light, because of low and rapidly changing sun angles. To this effect the classroom wing is well arranged with long facades on the north and south, although it could be thinner to do more work with perimeter light. Often orientation for daylight can benefit other sustainable strategies such as natural ventilation and passive heating/cooling [http://www.daylightinglab.com]. The Daylight Zone The “daylight zone” (the floor area that we can expect to illuminate with daylight) extends roughly 2 to 2.5 times the height of the perimeter glazing. This rule of thumb

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recommends a more shallow floor plan if daylighting uses only perimeter glazing. A deeper floor plan can be daylit but requires top lighting (skylights, monitors etc…) to balance light across deep rooms [http://www.daylightinglab.com].

Fig 3.14 The daylight zone [source / http://www.daylightinglab.com]. Large Program Spaces Location of large spaces like the library and gym can be influenced by the lighting criteria. Gymnasiums typically have loose lighting criteria because exterior views are not a priority and work or reading surfaces are absent. Therefore the gymnasium can be top lit with skylights or roof monitors. The absence of perimeter glazing means the skylights can be placed in problem locations like eastern facades without intrusive glare. Libraries have much more stringent criteria as it houses reading, teaching and researching which are all affected by glare and direct sun penetration. Libraries must be more carefully considered in orientation, internal program allocation, and sun control details. Site Scale Strategies: Library...

Fig 3.15 Elements of the design [source / http://www.daylightinglab.com].

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Using orientation to improve direct sun control The western wing of the school rotated off the north axis presents some challenging conditions with respect to direct sun penetration. At 26o the library now has a southeast and southwest façade, which allows lower angle morning and afternoon direct sun to shine in. On the library’s southwest side, the further the rotation, the earlier afternoon sun will penetrate this façade’s glazing. If the library were to be reoriented along the north axis with a strictly south and west façade direct sun would be controllable with the simple overhangs and light shelves on the south as designed. While the west is still difficult to control completely, architectural solutions could be developed to reduce times of direct sun penetration until after major occupancy hours [http://www.daylightinglab.com]. Building Scale Strategies: Classrooms...

Fig 3.16 Section of the building [source / http://www.daylightinglab.com]. Basic strategy for daylighting a double-loaded corridor: • Wash the inner-most walls of your perimeter rooms with diffuse daylight from above, by skylights or clerestory windows. • “Borrow” that light into the hallway with re-lite windows. • A daylighting strategy for a school should focus on illumination of classrooms and secondarily use that daylight to enhance less critical spaces (ie. the corridor). 1. Introducing clerestories or skylights on both edges of the mechanical attic allows daylight to wash the back walls of the classrooms. 2. Elevating the ceiling to follow the roof pitch will allow the daylight from the clerestory to penetrate deeper into the classroom space. 3. By Inserting a window into the upper portion of the corridor wall, the inner core of the building can borrow natural light from the classrooms’ daylight apertures. 4. Since toplighting is not possible on the first floor, increasing the floor to ceiling height will increase the height of the perimeter window and depth of daylight penetration to the rooms. Ground floor classrooms can be daylit to 60% of their depth with a perimeter clerestory at 11 feet and a sloped ceiling [http://www.daylightinglab.com].

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Building Scale Strategies...

Fig 3.17 Daylight Component [source / http://www.daylightinglab.com]. Building Scale Strategies: Case Study...

Fig 3.18 Case study [source / http://www.daylightinglab.com]. Component Scale Strategies... Windows The detailing of windows depends highly on their orientation. North facing apertures have no need for overhangs or sun control measures due to the absence of direct sun penetration. Overhangs and interior light shelves are appropriate on the south façade where daytime sun angles are fairly regular. East and west facing windows must be taken on a case by case basis. As an example let’s look at the south facing windows in the classroom wing. By placing an overhang at the top of the window the brightest part of the

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sky dome is effectively occluded. As strictly a view window, this design can be effective at reducing solar heat gain but does not harness daylight to illuminate the space. By dividing the window into its component parts we can minimize solar heat gain and use daylight to its fullest potential. Exterior overhangs dimensioned to the height of the view window will block direct penetration through September. Simultaneously, the daylight window above allows direct sun onto the light shelf and redirects it onto the ceiling. This method uses the ceiling as a light diffusing surface throwing light deeper into the space [http://www.daylightinglab.com].

Fig 3.19 Windows Details [source / http://www.daylightinglab.com].

Fig 3.20 Daylight Window [source / http://www.daylightinglab.com].

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Fig 3.21 Windows Details [source / http://www.daylightinglab.com].

Fig 3.22 Interior lightshelf [source / http://www.daylightinglab.com]. Common Material Selections... 1. View Window: Standard glazing section- Tinted to 50% Visible Light Transmittance (Tvis) often Low E to reduce heat loss. 2. Exterior Overhang: Can be almost any material depending on the architectural vocabulary of the building, common choices include Panel Systems, Metal Grate, Tempered Translucent Glass, Polycarbonates, etc. 3. Interior Lightshelf: Often made of painted plywood, gypsum board, MDF, perforated metal, translucent glass, etc. It is crucial that the top surface be matte finish white. A light colored bottom surface will help decrease contrast between the lightshelf and the window.

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4. Louver Blind: Horizontal adjustable louver blinds are very common. They range between very inexpensive standard aluminum louvers, to highly engineered specialty louver systems. 5. Roll-Down Fabric Shade: Aluminum roller housings for the roll-down shades are standard from several manufacturers. The fabric can be dark colored vinyl, or woven fiberglass fabric- which offers more flexibility with surface color differentiation, and creates less V.O.C’s off-gassing than vinyl. 6. Daylight Window: High performance glazing- High visible light transmittance (Tvis of 70% or greater), low solar heat gain coefficient (SHGC of 38% or less) [http://www.daylightinglab.com].

Fig 3.23 Common Material Selections [source / http://www.daylightinglab.com].

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3-2-3-2 Second example in this part is Project name: Walter Clore Wine&Culinary Center. Architect : Box Wood Group. Place : Prosser,Washington.(2004)

Fig 3.24 Analyses picture for the building [source / http://www.daylightinglab.com].

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Fig 3.25 Roof plan [source / http://www.daylightinglab.com].

Fig 3.26 Modeling for building [source / http://www.daylightinglab.com].

Fig 3.27 Sun movement and overcast sky dome behavior [source / http://www.daylightinglab.com].

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Fig 3.28 Simulation Equipments [source / http://www.daylightinglab.com].

Fig 3.29 Overcast sky simulation [source / http://www.daylightinglab.com]. The purpose for these studies is to simulate actual illumination levels inside the building during overcast conditions. An array of photocells is used to produce a three dimensional graph that represents the daylight factors within the class room. A daylight factor (df) is the percentage of the available exterior daylight that reaches the inside of the space. For example, a df of 2 equals 2% of the exterior sky dome illuminance on any given day [http://www.daylightinglab.com].

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Fig 3.30 Direct sun control [source / http://www.daylightinglab.com]. The purpose for these simulations is to better understand the patterns of direct sun on the site and in the building interior. Away from the direct beam of the sun, the sky is black. These tests are not meant to simulate actual illumination.

Fig 3.31 Upper level entry [source / http://www.daylightinglab.com]. The upper entry space was photographed in the overcast sky room to understand ambient illumination sources and intensities. The heliodon was used to simulate direct sun patterns and compare the three different window configurations within the thick southern wall [http://www.daylightinglab.com].

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Fig 3.32 Upper level entry [source / http://www.daylightinglab.com]. This photo comparison was taken to identify the contribution of a skylight over the reception area. The skylight serves to highlight a focal element in the space as well as balancing large amounts of illumination from east and west glazing. The south east corner also receives a healthy dose of daylight as it is the darkest corner of the space.

Fig 3.33 Lower level Dining / Café [source / http://www.daylightinglab.com]. The lower level dining / café space was photographed in the overcast sky room to understand ambient illumination sources and intensities. The heliodon was used to compare the direct sun patterns of three louver schemes and understand their effect on the light well [http://www.daylightinglab.com].

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Fig 3.34 Lower level Dining / Café [source / http://www.daylightinglab.com]. This photo stitch from the overcast sky shows the ambient light contribution from the various perimeter apertures as well as the large light well above. The dining area west of the kitchen is a little dark, creating some contrast. Care should be given integrating the electric lighting design to balance this contrast [http://www.daylightinglab.com].

Fig 3.35 Gallery / Display space [source / http://www.daylightinglab.com]. In the gallery/display area, the overcast skybox was used to simulate ambient illumination. Three dimensional graphs were produced for a clear understanding of light intensities in diffuse light situations. This could be an overcast day or anytime no direct sun is present. Heliodon videos were used to compare clear and louvered light wells.

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Translucent permutations were not simulated on the heliodon as there would be no direct penetration.

Fig 3.36 Open office Area [source / http://www.daylightinglab.com]. In the open office area, the overcast skybox was used to simulate ambient illumination. Three dimensional graphs were produced for a clear understanding of light intensities in diffuse light situations. This could be an overcast day or anytime no direct sun is present. Heliodon videos were used to compare the two light well geometries provided. Translucent permutations were not simulated on the heliodon as there would be no direct penetration [http://www.daylightinglab.com].

Fig 3.37 Open office Area ( Overcast simulation ) [source / http://www.daylightinglab.com]

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4-1 The application. 4-2 Final Conclusion.

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4-1 The application. Introduction... The need to provide climatic control inside buildings to improve comfort levels and hence productivity is very desirable. However, the cost of design or redesign to achieve the desired comfort levels has to be economically evaluated. With the on going energy/greenhouse emission reduction campaigns and in accordance with Environmental and Ecologically Sustainable Development (ESD) principles, the relevance of implementing sustainable energy technologies is now gaining the attention of building designers around the world. The problems associated with energy consumption such as cost, material depletion both renewable and non renewable and greenhouse gas emissions have provoked an increased awareness and willingness to strive for technologies that provide ameliorative measures which increase the sustainability of building stock [The Researcher].

Background... An area of this application will be a classroom located in Alexandria University, Faculty of Engineering, Architecture Department, in Administration building, fourth floor (Fig 4.1).

Fig 4.1 Plan For Fourth Floor in Administration Building [Faculty of EngineeringArchitecture Department]. This classroom has several problems such as low daylight level in space depth the classroom leading the users to close the windows and use the electrical lighting. Also the unequal distribution of natural illumination due to the space, the daylighting cannot reach in to big depth in the space so the daylighting covering small areas and users (Fig 4.2) (Fig 4.3).The question is how to increase daylighting level in the space? How to reduce heat load for lighting?

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Fig 4.2 Classroom plan [Faculty of Engineering-Architecture Department].

Fig 4.3 Photograph for Classroom [Faculty of Engineering-Architecture Department].

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Table (3.1) in chapter three explains that the daylight factor percentage should be less than 6 % and for each drawings table. These are the required percentage to achieve the visual comfort & clarity to the user helping in doing his functions and work in proper and comfortable way. The simulation program will be used in this study to know the places which have poor and high lighting levels to find out the weakness points which need treatment and increase the daylight percentage and how to do it [The Researcher]. The second step in this application after collecting data about the case study and problems facing it is to prepare the drawing to be entered into the simulation program “Ecotech” mentioned before in the background part to know the classroom behavior for the daylight throughout the year, it also can be reviewed throughout the different seasons.

Fig 4.4 Ecotect Interface [source://http/www.daylightinglab.com]. In every season the sun paths, the lighting rate and directions in the space will be reviewed and compare it to the other seasons to know the best and worst time for the daylight in the space, informing about or determining the space location is one of the required data in this application or program to do the simulation process accurately or appropriately in order to determine the sun movement paths in this region throughout the year [The Researcher]. This application works by entering the longitudes and latitudes and specifies the city location from the list of cities that lies in this region. In order to have an accurate simulation process, all the input data like the drawings must be correct. This application or program doesn’t deal with the complicated models while it deals with the simple models through studying the lighting behavior in the space. This model should reflect the dimensions, height, length of the expected location or places of the openings & its dimensions which give the designer the contours plan of the lighting in the space. This

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contours plan enable us to specify the strength and weakness points of the classroom and determine the ways to increase the daylight rate in the places that suffer from lack of lighting through the modern techniques like (“HLP” Horizontal Light Pipe Technology , “VLPs” Vertical Light Pipes Technology ) [The Researcher]. Simulation results in September:-

Fig 4.5 Daylight Analysis for classroom in September [Ecotect output].

Fig 4.6 Contours plan for classroom in September [Ecotect output].

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Fig 4.7 Sun path for classroom in September [Ecotect output]. Simulation results in December:-

Fig 4.8 Daylight Analysis for classroom in December [Ecotect output].

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Fig 4.9 Contours plan for classroom in December [Ecotect output].

Fig 4.10 Sun path for classroom in December [Ecotect output].

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Simulation results in March:-

Fig 4.11 Daylight Analysis for classroom in March [Ecotect output].

Fig 4.12 Contours plan for classroom in March [Ecotect output].

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Fig 4.13 Sun path for classroom in March [Ecotect output]. Simulation results in June:-

Fig 4.14 Daylight Analysis for classroom in June [Ecotect output].

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Fig 4.15 Contours plan for classroom in June [Ecotect output].

Fig 4.16 Sun path for classroom in June [Ecotect output]. The previous results of the simulation process in the classroom, and the counter maps show the main problem that face the classroom which result from the low rate of daylight especially in the middle of the classroom which is clearly obvious in the counter maps resulted from the simulation process and which is the current fact. The usage of the simulation programs output result in the desired objectives. These programs have proved their effectiveness & efficiency for the designer in this field

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although such programs are usually used in the earlier stages of the design process and the implementation stage [The Researcher]. Accordingly new two techniques will be displayed. These techniques increase the daylight rates in the classroom, and the places that suffer from the lack of daylight. One of the daylighting devices that have been evaluated involves a solar hood shading device to stop incident radiation from striking the south facing glazing but reflects light through a horizontal light pipe (HLP) above the suspended ceiling and then redistributes that light into the classroom place (Fig 4.17) [http//www.ask.com].

Fig 4.17 Horizontal light pipe technology (HLP) [source / http//www.ask.com]. While well known to domestic applications that have roof space to floor area available, vertical light pipes (VLPs) and skylight technologies are now playing a part in rooftop locations such as supermarkets and where substantial savings in lighting have been achieved (Fig 4.18).

Fig 4.18 Vertical light pipes technology (VLPs) with and without reflectors [source / http//www.ask.com].

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4 -2 Final conclusions. The following points can be concluded from the previous results, the comparisons between different methods to calculate the daylight factor, and the theoretical analysis of sustainability term:1- The realization of the sustainability concept in the design process preserves the electrical power for the future generation which is the common trend of architecture in the whole world to reserve the non-renewable resource, make use of the renewable natural especially daylight. 2- The entering of the daylight in the early stage of the design process help the designer to make use of much daylight, directing & choosing the places, and the dimensions of the openings and windows. 3- The more awareness of the architect is important as sustainability concepts in the design processes which contributes to a strong continuous architecture for many years. 4- The using of modern techniques and architecture processing that would increase the daylight rate in the space are very important to reduce the energy consumptions with the use of natural ventilation reducing thermal loads transmitted through openings. 5- The comparison between different methods to calculate daylight factor shows the benefit of using simulation programs in these calculations in space because of its highly accurate performance and the comprehensive or integrated look of daylight behavior provided to the designer through out the years. 6- Designers knowledge or analysis of the daylight behavior in the space throughout the year is helpful to choose the appropriate solution to reduce the problem arise after the implementation from lack of daylight rate in the space which will be cheaper and easier to address if it is discovered through the designing process using the simulation programs. 7- The simulation programs give accurate, clear, comprehensive results for the daylight rate in the space throughout the year. These results can be displayed in different forms like the counter maps, tables & flow charts which mainly direct the designer in the design process. 8- These programs are capable of doing the simulation process for any space anywhere around the world by entering the longitude and latitude of this place to simulation the sun paths or tracks in this place to get the a correct, and the most likely results. 9- It is not difficult for the designer to learn how these programs work because of the available tutorial on the internet. Also the speed of these programs in performing the simulation process enhance the designer to learn these programs

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to save the effort lost or consumed in the linear algorithms or mathematical operations to get the same results but with less accuracy and high error rate. 10- The more awareness of the designers is as important as the simulation programs in the early stages of the design process to define the problems that might arise after implementing the design in order to solve these problems quickly to reduce the costs, energy consumption, to rely on the daylight as much as possible. 11- Both daylighting and natural ventilation are critical climatic control components that should be considered for all building sticks in efforts to reduce energy consumption and to increase the sustainability. 12- Increasing the different daylight rates in the space while reducing the transmitted direct thermal load into the space through the natural ventilation. This action reduces the building operational cost of the conditioning, and electrical power overuse which is the main objective of the sustainability.[The Researcher].

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References Book and Periodicals Paper: Erik Andre , Jutta schade , " Daylighting by Optical fiber ", Periodicals Paper, Department of Environmental Engineering , Lulea University Of Technology , Division of water resources engineering , pp. 11-17 (2002). Dr. Mohamed Anwar Mohamed Fikry , " Daylighting , A respected Design Approach , Fifth paper ( single ) " , Al-Azhar Engineering sixth international conference , Cairo , Egypt , pp.1, September ( 1- 4- 200 ). Gro, Harlem Brundtland, " Brundtland Report " , pp. 43, Published in (1987) . Robbins Claude .L , " Daylighting Design & Analysis " , United States , Van Nostrand Reinhold,New York, NY , pp. 3-188 ( 1985 Jan 01) . Dr. Mohsen M. Aboulnaga , " Advanced Daylighting & Lighting Technology For Sustainable Architecture Design " , Submitted as part the promotion requirements for the title of professor in Architecture & Sustainable Design , Department Of Architecture , College Of Engineering , Cairo University , pp. 2-32 (2003). G.F. Menzies, J.R Wherrett, " Windows in the workplace: examining issues of environmental sustainability and occupant comfort in the selection of multiglazed windows", Periodicals Paper, School of the Built Environment, HeriotWatt University, pp. 1-5, (2004). Dr. Nagwa Ahmed Zaki , " Building Eenestration Daylighting " , Thesis Presented To The Faculty Of Engineering , University Of Alexandria , pp. 45-51, (1999). Gudio Petinelli and Christoph Reinhart , " Advanced Daylight Simulations Using Ecotect // Radiance // Daysim , Getting Started " , pp.10-33, (2006) . Ramses Wissa Wassef , " Habib Georgy Sculpture Museum " , Gizza , Cairo , pp. 3-5, (1974) . Christoph Reinhart , " Kennydale Elementary School.pdf " , Renton , Washington ,(2004). Christoph Reinhart , " Walter Clore Wine & Culinary Center .pdf " , Prosser, Washington , (2004). Shane West , " Improving the sustainable development of building stock by the implementation of energy efficient, climate control technologies ", Broadway , Sydney , pp. 284-285, ( 2000). Oxford Dictionary, pp.140, Published in (1999).

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Lechner, N.M, " Introduction to daylighting part I , light forum", pp. 5-10,(2002). Whitehouse, David, " Turning Night Into Day ", pp. 20 -25, (1999). Ittenbach, Reitmair, "Systems Generating Systems", pp. 143, (2003). James Steele, "Sustainable Architecture", pp.125, (1998). N. Larsson, "Green Building: An Overview, Natural Resources Canada", pp. 74, (2000). Tregenza, P. and Loe, "The design of lighting", London, pp. 454-460, (1998). William-Olsson, Margarela, "Solbrist kan orsaka benbrott", pp. 210- 220, (2002). Christoph Reinhart , " Ecotect, Daysim, Skyvision program " , (2005). Web source: http:// www.greatbuildings.com (Access Date 20-7-2005). http://www.arch.mcgill.ca/prof/reinhart/software/Radiance.htm (Access Date 128-2005). http:// www.radiance-online.org (Access Date 12-8-2005). http://groups.google.com/group/daysim (Access Date 15-8-2005). http:// www.ecotec.com (Access Date 15-8-2005). http:// www.Daylightinglab.com (Access Date 30-8-2005). http:// www.ask.com (Access Date 20-1-2006). http:// www.Energy Efficiency and Renerable Energy.com (Access Date 30-1-2006). http:// www. DOE High Performance Buildings.com (Access Date 15-6-2006). http://irc.nrc-cnrc.gc.ca/ (Access Date 20-7-2006). http://www. Energy Efficient Technologies: Daylighting Design. (Access Date 20-7-2006).

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