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DISCUSSION ABOUT THE APPLICATION OF ENERGYPLUS IN CLASSROOM OF EDIFICATION UNlVERSITY: METHODS OF COMFORT X THERMAL COMFORT X CLIMATOLOGICALLY VARIABLES - INTERNAL AND EXTERNAL Moraes, Clélia Mendonça de *; Ismail, Kamal Abdel Radi **

* Undergoing PhD Student, Universidade Estadual de Campinas - Unicamp, Faculdade de Engenharia Mecânica - Unicamp - Rua Mendeleiev, s/n - Cidade Universitária "Zeferino Vaz" Barão Geraldo, e-mail:c1é[email protected] ** Full, Professor Universidade Estadual de Campinas, Unicamp - Faculdade de Engenharia Mecânica - Unicamp - Rua Mendeleiev, s/n - Cidade Universitária "Zeferino Vaz" Barão Geraldo, e-mail: [email protected] SUMMARY

A new approach was applied to evaluate therrnal comfort has been evaluated crossing outside-inside temperatures obtained from EnergyPlus buildings evaluation tools, comparing comfort therrnal sensations responses obtained from questionnaire applications. A c1assroom was probed experimentally to identify its real therrnal behaviour and the aim of this study was to identify perforrnance and the other centred on the human behaviour. This preliminary study case is the introduction for a methodological approach for understanding the abrangency of human comfort methods such those presented by Fanger, Humphreys and Givoni, trying to understand how they establish the limits ofthe comfort zone for human metabolismo Understanding the necessity of quantifying dispersions on human thermal comfort sensations due to acc1imation issues especially for a country with a large range of latitude variations like in Brazil, points to the probability of reducing energy cost with facilities by reducing the difference between inside and outside temperatures. Keywords: experimental and simulations thermal perforrnance, human therrnal comfort behaviour and thermal human comfort methods

INTRODUCTION

This research introduces a new methodology to evaluate the therrnal perforrnance ofbuilding envelope and its correlation with human comfort sensation, trying to deal with the human issue in the deterrnination of therrnal comfort as well as the acclimatization issue through evaluating the outcome of questionnaire applied, which were similar to the Fanger's, Humphreys's, Orstein's and Leite's 2002 proposed model (1970/72/92 and 2002). In this work, it was focused the application of the software Energy Plus in classroom, comparing comfort thermal sensation responses obtained from questionnaire applications. For that, a model c1assroom was equipped with therrnocouple type J, wind velocity and humidity ranges and monitored from 2004 to 2005. The data obtained were facing to the students'

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questionnaire answers, which were applied simultaneously to the data acquisitions. The goal ofthis comparative analyse was performed to get insights into the identification ofthe human dispersion on thermal comfort sensations, which were interpreted under logic fuzzy point of view. We will present the panorama about ofbuilding and energy consumption, climate, architecture and thermal comfort. Moreover, discussions about the elaboration of an integrated project correlating the passive and active technology consequently the impact on the consumption of energy. METBODS Projeet sustainability and energy consumption Sustainable constructions are physic references ofthe world ofmaterials and constructive techniques, integrating architecture and context. The local climatic characteristics are determined in the configuration of the form and coverings of an ecologically conscious building. The comfort questions possess a basic paper in the definition of the building of less environrnental impact and more energetic coefficient. The great purpose of the cooling, the heating, the ventilation, and the artificial illumination is to make the bridge between what it is expected and what it is needed from the environrnental comfort and the building. In the formation of this bridge the difference between the value of the architect and the engineer participation varies according to the seasons of the year, geographic position, program of use, formal aspects of the construction and physic characteristics of its materiais. These concepts are present such in the beginning ofthe elaboration of an architecture project, when the promotional agents of the civil construction, architects, engineers and designers trace the first risks in the paper establishing important aspects related to the dimensions of the lot and the diagram if insolation. At this moment, important things about the future of the thermal cornfort and energy consumption can be determined. At this moment it can be observed that the building must be thought and integrated to the constructed environrnent and the local climate, determining formal and functional aspects, adjusting material and techniques of the project. Integral design uses passive and active technical solutions in the elaboration ofthe architecture project. In the beginning when the traditionallines of direction of projects adopted initially are not enough demonstrated it could be appealed to the passive systems of cooling or heating, that is, the mechanical equipment that normally implies in little additional cost and little maintenance. In case that these passive systems are not enough, active systems are required, that is the mechanical equipment that implies in cost of installation, functioning and maintenance. With the objective to provide to the maximization of the comfort and minimization ofthe energy use, one analyses ofthe climatic conditions ofthe one determined local one must be carried through. The data of climatic conductions are normally presented in form of graphic from which it is possible to get information of variations that occurs in different seasons of the year and the interrelation between the climatic varieties. Many times the graphic of climatic conditions contain the borders of condition of human thermal comfort with base for evaluation of the levei adequacy/inadequacy of the external climatic conditions, the necessity of heating or cooling as well as the conditions of project to improve the internal conditions: the bioclimatic letters. The Brazilian civil construction presents a lack of legal instruments to qualify energy and thermal performance of architecture projects. The construction of buildings of low quality and

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disregarding the local climate characteristics, forces users to be permanently in airconditioned envirorunents, as for cooling as for heating. The definition ofthe limits of thermal comfort acceptable in Brazilian constructions will have important implications in the construction project and posterior in the consumption of energy ofthe building. The countries that have adopted legislation to the thermal performance of buildings based on norms and technical criteria, they have demonstrated that has been possible to reduce the consumption and upgraded energy performance in the last two decades. France, for example, between 1973 and 1989 economized 42% in the sector applying a new legislation in the civil constructions. The French model started to be adopted in ali the Europe. In the beginning of 90's, the USA adopted a new legislation related to the rational use of electric energy in all the country; even for the states, which already possessed its legislation. So, a new concept was introduced in the building constructions by setting mies to guarantee the rational use of the energy and comfort to the users, which was known as Efficiency Energy in Constructions. At the end ofthe 90's, Brazil started to have serious problems related to the production and consumptions of energy. ln 2001, a blackout, that reached all the country, showed theimportance of the rational use of the energy and from that, the adoption of new devices in the building constructions were stimulated. The concept of Efficiency Energy in Constructions was adopted in Brazil only at the end of 2006 and the regulation for voluntary labelling of levei of energy efficiency in commercial buildings and public services by the Managing Committee ofPointers and Levels ofEnergy Efficiency - CGIEE, approved it. The consumption of electric energy in Brazil is around 43% in residential and commercial sectors. According Juan and Lúcia Mascara, 20-30% ofthe energy consumed, it would be enough for the functioning ofthe construction; 30-50% ofthe energy consumed are wasted due to inadequate controls of the installation, maintenance and also for bad use of it; 25-45% of the energy is consumed improperly by bad orientation and for inadequate project drawings. For instance, comparing a same project construction in different places, Belém in the North and Porto Alegre in the South of Brazil, it is observed an increase up to 80% of the electric energy demand, when it compares Belém and Porto Alegre. This fact demonstrates the necessity to adopt energy politics taking in accounting the Brazilian climate variation the use of passive and active techniques for the elaboration of sustainable projects construction. Thermal comfort aod eoergy io c1assroom io the University of São Paulo The envirorunental factors that affect the human comfort are: the average radiating temperature, humidity and air speed. Fanger developed a thermal comfort model based on thermal sensation ofthe body. This model is based in the calculation ofthe predictable average vote (predicted mean votes - PMV) and temperature effective that in the comfort zone present linear in the temperature of air and average radiating temperature, and quadratic in the dew point and that it can be calculated without interaction as well as the atmospheric pressure. To apply Fanger's model in Brazil, it would be important to add the atmospheric pressure as a variable, once that the weather variation occurs due to movement of air mass and the meeting between hot and cold air mass, which brusquely modifies the temperature of air. As a model of study, we took a classroom in the University of São Paulo, which showed the same common problems found in the Brazilian construction related to the energy consumption and thermal comfort problems. However, the buildings in the University have peculiar architectural solutions that are, in greater or lesser degree, adapted to the climate. USP architecture, all over the campus and can be divided into three distinct phases:

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1. l sr phase - Buildings constructed in the beginning of 60's: the architectural style is con erned with the local climate. The architecture has the following characteristics: a) high thermal inertia: b) cement lab or ceiling re-covered by adobe roofing tiles; c) the high height from floor to fIoor; d) window wall rate around 50%; e) naturallighting; f) individual control of comfort conditions. 2. 2nd phase - Buildings constructed between 1960 and 1975: rupture regarding elimate due to aestheric values. The architecture has: a) reduced thermal inertia; b) cement lab without protecrion in the covering; c) high window wall rate (elose to 100%); d) high amount of openings to the outside, some ofthem without elosing possibilities; e) large voids; f) difficulty in controlling comfort conditions. 3. 3rd phase - Buildings constructed from 1975 until now: total disruption with reference to the values ofthe previous phases. The architecture has the following characteristics: a) buildings with an average thermal inertia; b) cement slab covered by asbestos-cement roofing tiles; d) low height from floor to fioor; e) window wall rate higher or equal to 60%; f)' presence of "thermal bridges"; g) lack of control of comfort conditions or control made by air-conditioning systems. h) The present trends that emphasize energy consumption and comfort controlled to the following proposals for a next phase. The architecture ofthese new buildings is expected to be based on projects with the appropriate thermal and energy conditioning with the following characteristics: i) respect for the local climate; j) environments less dependent on conditioning systems; j) adjusted thermal inertia; I) greater presence of natural illumination; m) window wall rate around 50%; n) adequate treatment for possible thermal bridges; o) long-term savings due to smaller electric energy consumption. The goals to be reached by the creation of an energy efficiency regulation in architecture are related to the reduction of the energy consumption. This reduction, in the existing buildings, could be achieved through the identification of possible interventions by the use of passive systems that could reduce the thermal loads inside the buildings at the same time as they improve comfort conditions. In the buildings that are in the preliminary design phases, the regulation has as main purposes to develop the use of naturallighting, to reduce both conditioning equipment use and thermalloads. A survey on severa! buildings in the campus of University of São Paulo showed that the typical equipment used for thermal comfort are unitary air conditioning and split systems (near 90% oftotal). This equipment is used mainly in teacher's offices, laboratories and elassrooms. Central air conditioning systems (10% of total) are applied on large environment such as auditoriums, libraries and museums. This study also allowed checking that, for the unitary equipment, the maintenance is quite deficient, which implies in poor efficiency during operation and increasing energy consumption. It should be pointed out that air conditioning represents 30 to 40% ofthe total energy consumption of the analysed buildings. Besides it was verified a lack ofpurchasing control policy which implies in most ofthe cases on acquisitions of oversized equipments and improper use of air conditioning systems. Based on this scenario, two main goals were set to the air conditioning systems project in order to reduce energy consumption, i.e.: a) Establishment of maintenance policy for actual air conditioning systems; b) Directives for purchasing new air conditioning systems/equipments.

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Concerning the first one, the goal is being pursued in two ways: a) Development of internal maintenance procedures for unitary air conditioning systems; b) Training courses for technical staff on maintenance practices. These activities will provide guidance in good practices related to the maintenance of unitary air conditioning systems, avoiding several problems in the operationlmaintenance of such systems. The training courses was taken by a group of the technical staff with minimal or even no prior background on maintenance of air conditioning systems. This course will fill a lack of qualified labour, especially in the countryside campus. Concerning the directives for purchasing goal, the main objective is to analyse how air conditioning systems and equipment are purchased at USP nowadays and to propose recommendations that should guide USP staff to purchase the proper equipment for a given application, taking into account characteristics such as type of system (unitary or central system), conditioned area (classroom, library, etc.) and system capacity. Besides those goals, a study was made where an analysis of selected areas with air conditioning problems were performed. Based on such analysis, a retrofit was implemented in order to optimise the energy consumption without damaging thermal comfort. This study is important in order to quantify the impact of using proper air conditioning system type and capacity and, as a consequence, providing significant reduction on the energy consumption. The selected areas include classrooms, laboratories and computer rooms. For this goal, energy consumption of35% was achieved through proper selection of air conditioning equipments. It should be also pointed out that 30% oftotal energy consumption ofUSP is related to air conditioning and refrigeration systems. Therefore, more efforts should be done to reduce the contribution of such systems. Through these actions, it is expected to make the USP staffto be more conscious ofthe adequate purchase and use of air conditioning. As a side effect of this actions, it is expected an increase in equipment life, decreasing the maintenance costs, and the reduction of energy consumption. The thermal comfort in the interior of the constructions depends on aspects as insolation, dominant winds and characteristic of surrounding, beyond the positioning ofthe building in the lot, type of façade, thickness of walls, employed dimension of the openings and materials passive systems consist oftechniques. Such techniques are used in the projects ofthe constructions in Brazil. When these techniques are demonstrated insufficient are used the active systems with mechanized equipment that implies in additional cost of installation, functioning and maintenance. However to if considering the climatic characteristics of Brazil that is countries with tropical climate of altitude it is verified to be able to use the fusing of these techniques and to allow that in days where I did not demand cooling in surplus the windows you could be opened to renew air internal. The conditional air system is complementary resource that, when planned well, it helps to guarantee of well being with reduced costs of operation and maintenance. The proposal of conditioning of air in a building is to supply a surrounding healthful insurance and its occupants. RESULTS The experiments were performed during the 2004 and 2005 years and the outdoor conditioning showed extreme temperature peak from 27.28 to 29.3°C, under approximately 85% ofrelative humidity and the indoor conditioning ofhuman comfort sensations

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temperature peak from 21.77 to 22.36°C approximately 70 to 90% ofhumidity. The crossing outside-inside temperatures obtained from CSTB, EnergyPlus, and Arquitrop buildings evaluation tools and the comparison of comfort thermal sensation responses obtained from questionnaire applications they were associated to determine the limiting condition ofthe thermal comfort. In spite ofEnergPlus showing some difficulties such as digitalisation ofthe points and the interface with AutoCad, and also in the way that the software recognizes the construction compartrnents, the evaluation of result obtained is satisfactory and is closer to answers of the students' questionnaires. So, the EneryPlus has shown to be a useful tool to evaluate the thermal performance and energy consumption of the buildings. PSYCHROMETRY

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Çhart Overlay ~

l'IdFl;'WA_1

"10,,1

~Date:

Activtty

Sedentary

.••••••••. t•••••• · =-,=,,"-:!.II

Extreme internal temperature Arquitrop

29.3 °C

08b45rnin

Energyplys

26.00°C

16b

Cstb

27.28°C

9h

11I O

• O

Experimental measurements 24.63°C

16h45rnin

DISCUSSION Nowadays, simulation has been a useful tool and very important to investigate temperature oscillation, but it cannot be used to evaluated the thermal behaviour of a building or the distribution ofthe occupants' sensation. So, it is clear that the improvements must be done and new models investigated with the aim of decreasing the discrepancy between the experimental and theoretical studies. Better simulation tools would help to elaborate more efficient construction project focusing in the thermal comfort and the energy economy. Taking this point in accounting, we have investigated the efficiency of some simulator and compared with our experimental measurements. From the result analyses performed with CSTB, ARQUITROP and ENERGYPLUS software, it was possible to observe that the classroom walls work as accumulators of heat. This heat is absorbed during ali day and cannot dissipate it during the night. Because of this effect, the internal temperature of the classroom increases and causing a great thermal discomfort to the students. Ali models investigated showed a temperature oscillation from 27.28 to 29.3°C, which associated to sedentary activities in the classroom and high relative humidity, approximately 85%. The questionnaire answers also showed that the thermal discomfort is higher during the afternoon than in the morning, the dissatisfaction degrees were 70 and 20% respectively. ISO-Fanger stipuIes that the leveI of the discomfort rate accepted, it should be equal or less than 20%.

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The temperature monitoring showed that the high peak temperatures occur elose to the end of tbe classes around 17 o'elock. We observed that the high peak temperature obtained with the simulation through EnergyPlus was 26.0°C o'clock and elose to 16 o'elock, while Arquitrop showed 29.3°C elose 9 o'elock and for CSTB the value obtained was 27.28°C elose to 9 o'clock. So, the simulation performed with EnergyPlus resulted in the best values of temperature oscillation and eloser to the experimental resulted

FUTUREWORK Besides the above-mentioned methods, further work must be developed applying the methods Fanger, ASHRAE, Givoni and Humphreys. Afterwards we will simulate the rich gamut of thermal comfort sensations detected in the poll carried out with the students through the Universal Fuzzy Controller.

ACKNOWLEDGEMENT UNICAMP -Faculdade de Engenharia Mecânica, Prefeitura Municipal de Araraquara, CAMPEBELL DO BRASIL, University of São Paulo (Geography_USP (USP) and FAU_USP (SP) for providing the equipments used in the experimental research, the Astronomy and Geosciences Institute (IAG) Prof. Amauri P. Oliveira and John, V. Me Sato, Neide M. N. the Polytechnic School - Dept Civil Eng. from USP for the climatology data of the campus and professors, students, workers at the Mechanical Engineering: Polytechnic School at USP.

REFERENCES 1.

ASHRAE. 1992. ANSVASHRAE Standard 55/1992, Thermal Environrnental Conditions for Human Occupancy, Atlanta: American Society ofHeating, Refrigerating, and Air conditioning Engineers, lnc. 2. BARUCH, GIVONI 1062. Influence ofwork and environrnental conditions on the physiological responses and thermal equilibrium of manoHaifa: Israel Institute of Technology, 1962 3. MORAES, C.M.; TRIBESS, A.; FRANCO, I.M.; ANDRADE, M.T.C.A, ANDERS, G.C.; OLIVEIRA, G. Experimental study ofhuman thermal comfort sensations in elassrooms: Complementary evaluation with methods of building envelope performance and questioner application. Holland, 2004. Annals Holland: Eidhoven, 2004. P755-760. 4. MORAES, C.M.; BRASIL, R.M.L.R.F.B., TRIBESS, A.; FRANCO, I.M. Preliminary results of human thermal comfort evaluation for altitude tropical elimate: comfort methods x comfort questionnaire. Switzerland, 2005. Annals Clima 2005. Switerzaland: Lausanne,2005.pl-6. 5. RAU, THOMAS MARTIN Unexpected Sources - Daily Innovation. Switerzaland, 2005. Annals Clima 2005. Switerzaland: Lausanne, 2005. pl-6. http://www.master.iag.usp http://www.cptec.inpe.br http://www.periodicos.capes.gov.br http://www.labeee.ufsc.br/eletrobras/reg.etiquetagem. voluntaria.html http://www .energplus

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