Design of Energy Efficient Residential Building in a ...

Proceedings of the 12th INDIACom; INDIACom-2018; IEEE Conference ID: 42835 2018 5 International Conference on “Computing for Sustainable Global Development”, 14th - 16th March, 2018 Bharati Vidyapeeth's Institute of Computer Applications and Management (BVICAM), New Delhi (INDIA) th

Design of Energy Efficient Residential Building in a Tropical Region using Sustainable Techniques Misbah Bashir

Owias Nazir

Mohammad Jamal Al-Haj

School of Civil Engineering Lovely Professional University Phagwara, INDIA Email ID: [email protected]



Ansara Jeelani

Bishnu Kant Shukla

V. Rajesh Kumar




Abstract— Need for sustainable development is ever increasing and humanity is at a point where each man must learn to see beyond his animal instincts and selfish desires. At this crucial juncture where man must learn that his actions have a consequence which is beyond his control, non-sustainable engineering comes as an increasing threat. In this paper, study has been done to design a house which shall not only save energy but also provide much more comfort for its residents. The adoption of basic principles and laws and incorporate passive techniques of cooling and heating into building a home that shall stand firm against the changing course of nature, against the scorching heat of summer as well as the fierce chill of winter and provide comfort within with a minimal use of energy. A passive house was designed considering a tropical region, where summers as well as winters are extreme. In summers, the working process included air flow path and in winters ventilation with air exchange technique was used. The study hopes that this building shall not only serve its materialistic function but also insist in the minds of the billions of people a sense of responsibility towards sustainability. Keywords— Energy Efficient Buildingt; Sustainability; Passive Cooling; Tropical House

I. INTRODUCTION With the acknowledgement of the consequences that the over-use of natural resources bring to the fate of mankind as a whole, architects and engineers are forced to design innovative and efficient buildings[1] which not only reduce the energy requirements of the building[2] but also the energy used in constructing the building. This constraint in the resources available to mankind has enabled designers to develop various models and standards for low-energy usage such as the passive houses[3], net-zero energy buildings[4], energy plus buildings[5], green buildings[6] etc. The common factor behind most energy efficient building is that they are developed in the harsh cold climates of Europe [7]. Models

such as the passive house model [8], from which we shall adopt certain design concepts, were introduced in Germany where temperatures go below much lower than freezing temperature. Hence, most energy efficient buildings are meant to be suitable for cold climates and not tropical ones [9]. Thus, the main objective or difficulty of our project shall be to modify these designs into making it suitable for a climate prevalent in India. II. MATERIALS AND METHODS A. Types of Solar Heating and Cooling Systems a) Active: Active solar systems use external sources of energy to power blowers, pumps and other types of equipment to collect, store and convert solar energy. Once energy from the sun is absorbed, it is stored for later use. b) Passive: A passive solar system does not involve mechanical devices or the use of conventional energy sources. It is attained by a simple design consideration through which heating and cooling takes place automatically. Now, the aim of our project is to design affordable houses with low energy costs for the middle class Indian bourgeois, , we look toward the passive systems for guidance. The best existing model would be the passive house model which relies completely on passive technology for its solar heating and cooling and hence we shall base our house on the existing passive house design principles. In the northern hemisphere, the sun rises and sets on the south and hence, a most efficient orientation is one where the longer faces of the building is placed North-South. But the obvious problem with regard to the solar heat gain is that:

Copy Right © INDIACom-2018; ISSN 0973-7529; ISBN 978-93-80544-28-1

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Proceedings of the 12th INDIACom; INDIACom-2018; IEEE Conference ID: 42835 2018 5 International Conference on “Computing for Sustainable Global Development”, 14th - 16th March, 2018 th

a)

In summers, the sun is undesirable and all direct sunlight must be avoided.

b) While, in winters, sunlight must serve as a source of heat gain which shall passively heat the house

Which implies that L= 0.8 m is the minimum length from which the sun rays hit the southern wall. Hence, windows can be constructed based on this length.

Fig. 2. Overhang Design

Fig. 1. Orientation of a Building

These seemingly contradictory aims can be achieved by simple design consideration in overhang of the building. B. Overhang Design During summer, the approximate angle the sun makes with the vertical axis is around 85o and during winter it is approximately 50o thus making a difference of about 45o in the angle of the sun rays. We shall use this knowledge of alignment to design our overhang: For summer sun angle of 5o: tan(5) = (length of overhang)/(height of the building from ground level) Therefore, length of overhang = tan(5) x height of building from ground level = tan(5) x 7.5 ≈ 0.65 m Hence, length of overhang = 0.65 m For winter sun angle 50 o: In winter, the sun makes an angle of around 50 o with the vertical axis. Hence, if we consider the length of overhang as 0.7 m, we can find the maximum level of window pane. From Fig.2, .we get, tan(50) = 0.7/L where L = length of masonry till the window Therefore, L = tan(50) x 0.65 = 0.77 ≈ 0.8 m

C. Thermal Insulation Heat loss of different components of a building can from windows, external faces, ground slabs, thermal bridges and roof

Fig. 3. Thermo-graphic image of Left: a conventional house; Right: A passive house

From the thermo-graphic image (Fig. 3), it is clear that heat loss occurs mostly in the windows and areas where the structural member penetrates through the walls. D. Techniques of Insulation The maximum amount of heat loss occurs through windows. It can be prevented by utilizing a special type of window called a “triple glazing window. Also, air-tightness is achieved by careful application of appropriate membranes and tapes or wet plastering in concrete construction within the building envelope


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Design of Energy Efficient Residential Building in a Tropical Region using Sustainable Techniques

E. Components and Principles of aa Sustainable Building with Passive Technology in a Tropical Region The following components/principles are adopted for our purposes: 1) A Solar Chimney: As the name suggests, a solar chimney is an empty space which is used to create convection current which will regulate the room temperature. It works on the principle of “Stack Effect”. Stack effect is the movement of air into and out of buildings, chimneys etc, resulting from air buoyancy. Buoyancy occurs due to a difference in indoorto-outdoor air density resulting from temperature and moisture differences. It works as follows:  During the day solar energy heats the chimney and the air within it, creating an updraft of air in the chimney.

kitchen, bathroom etc.The air flow diagram will be described below when we discuss the working 7) Windows: Triple glazing windows can be used. 8) Roof: To reflect the sun’s rays and to avoid heating due to radiation from the roof, we can use white paints, radiant barrier and green roof (plantation on rooftop). Since a green roof looks both pleasing and as well as helps in fighting global warming, we shall use a green roof for our passive house.

 The suction created at the chimney's base can be used to ventilate and cool the building below. 2) Hollow Area between the North Walls: Along with the solar chimney, we have also provided hollow walls on the north side as well. This creates a passage for the convection current to circulate throughout the building 3) Hollow Roof Area: The hollow roof is also a part of the design to allow the air current to flow. 4) Large Roof Vents: Large roof vents are provided along the length of the roof. These will be closed or opened depending on the need. Its use will become apparent when we describe the working of our passive house. 5) Large Diameter Underground Pipes: These pipes are placed underground in the north-south direction as well as in the east-west direction. This serves two purposes:  The circulation of air though the building

Fig. 4. Plan Showing Alignment of Underground Geothermal Pipes

III. WORKING PROCESS A. Summer The working process including the air flow path and other mechanisms have been shown in the Fig. 5.

 Entry of cool and fresh air in summer and moderate air in winter. “Geothermal energy” has been used to solve the problem of our dual-purpose passive house viz.,  Passive cooling in summer  Passive heating in winter a) Principle of Geothermal Heating and Cooling: The earth has an ambient temperature of around 15 degrees Celsius throughout the year. The use of geothermal energy source to serve the dual purpose viz. passive cooling and passive heating. The fresh air intake is passed though underground pipes that run EAST – WEST which brings in fresh air with stabilized temperature. During summers, the hot outside air is cooled by the earth before entering the house and during winters, the cold outside air is warmed by the earth before entering the house. This can be seen visually from the plan drawn using Sketchup layout (Fig. 4). 6) Internal Pipes for Air Exchange:Fresh air entry pipes are provided inside the walls in bedrooms, living room area etc. Stale inside air is removed through exhaust fans near

Fig. 5. Working in Summer

The following process takes place in summer:  The large vents on the roof are opened. This creates a passage for the air to move upward and flow outside.  As the temperature rises, the hot air in the solar chimney as well as the hollow wall rises upward due to “stack effect”.


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Proceedings of the 12th INDIACom; INDIACom-2018; IEEE Conference ID: 42835 2018 5 International Conference on “Computing for Sustainable Global Development”, 14th - 16th March, 2018 th

 This creates a pressure difference between the inside of the house and the outside.  This pressure difference causes fresh air to enter from below through the underground pipes.  Hot stale air within rooms is expelled outside, into the solar chimney using exhaust fans placed in kitchens, bathrooms etc.  Thus, not only is temperature maintained but air quality is greatly improved.  The incoming air is cooled by the ambient temperature of the earth through geothermal cooling.  Mechanical cooling becomes almost unnecessary except for maybe ceiling fans B. Winter The working process for winters has been shown in the Fig. 6.

scientific principles can be adopted to greatly reduce the energy demands of a house. These basic concepts which can be used by anyone anywhere are not costly. As such, there exists very few passive houses or near-zero energy homes in India at present. The fact that we are a developing nation must not stand against our need to be responsible human beings who shall take care that his needs do not cause his demise. It is our belief that further research in building a passive house in India will not only provide the country with low-energy, comfort homes but also give them the sense of responsibility they need to feel toward the environment and toward nature as a whole. This seemingly simple concept of a low energy house can serve as an impetus to the upcoming generations of the nation. The very acknowledgement on the part of young minds that they are living in an eco-friendly house will give them the sense of responsibility that our nation and the whole of mankind as a whole needs. REFERENCES [1]

[2] [3]

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[5]

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[7]

Fig. 6. Working in Winter

The following process takes place in winter: 1. The large roof vents are closed. This creates a heavily insulated house with small vents open for escape of air. 2. As the sun heats up the South side, the air within the solar chimney gets hot.

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3. This hot air in the south side rises upward and through the hollow roof space. 4. The air on the north hollow walls is cold and hence it falls down. 5. Thus, convection current circulates the entire building maintaining the temperature. IV. CONCLUSION The passive heating and cooling techniques combined with the energy harvest methods can create a house which is not only energy efficient but also provides a great comfort. The basic


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