Climatic Adaptation: Impacts On The Thermal Comfort Of Offices Buildings At Curitiba - Brazil.

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1 Climatic Adaptation: Impacts On The Thermal Comfort Of Offices Buildings At Curitiba - Brazil. Antonio Augusto P. Xavier and Ivan Azevedo Cardoso Technological Federal University of Parana UTFPR Curitiba Brazil Corresponding ivanac@utfpr.edu.br SUMMARY Concerns about energy efficiency, has brought new constructive trends researches. Aspects as environmental comfort is quite important, with regard to new constructive technologies, showing the need of standardizing Brazilian buildings to acquire thermal comfort. The necessity of new internal environment data in buildings has motivated surveys about it. The proposal is to present the constructive typologies of buildings and their indoor variables in Curitiba city, Parana state, South of Brazil, relating it to the Bioclimatic Chart, proposed by Givoni [1], for countries in development. This work analyzed the constructive characteristics of 39 commercial buildings and environmental variables measured in internal environment of each one. The data was separated in winter and summer being inserted in the Bioclimatic Chart equivalent to Curitiba climate. That way it has verified that constructive typologies were more suitable for the region. INTRODUCTION The use of new materials and technology as a way to identify enterprises of great value went beyond the good sense necessary for building new constructions. With the massive use of lighting and air conditioner equipments, the consumption of electric energy took a great deal of proportion aggravating the problem of energy supply. Especially from the decade 1970 and with the population increase on the decade 1980 and more recently in 2001 with de problem called a black out, the energetic situation in the country has been receiving especial attention. Due to such preoccupation, new constructive tendencies have arisen, and aspects as energetic efficiency and ambient comfort have become of extreme relevance concerning to the new constructive technologies, showing the need of bringing the construction of new buildings back to normal taking into consideration concepts as energetic efficiency hitched to the thermal comfort. This way, the need of new data and parameters about ambient conditions in constructions motivated the production of works all over Brazil. In order to study the thermal comfort evaluation methodologies of constructions several works have been developed. According to Neto [2], the proposal norm structure is quite wideranging and seek not to shut the procedures for building national character regulations or yet specific regulations for States and/or regions. Janda, Katryn and Busch [3] carried out some information about sixty countries with the purpose of getting the experience obtained in normalization of many countries focusing areas where the results can be applied and developed in an effective form.

2 Seeking for solutions energetically efficient, it started for adopting passive measures in order to get human comfort, that is, measures which do not involve energetic wasting for it. For this checking, it must take into consideration the local where the buildings are found, that is, its climatic region. According to Goulart [4] the climate in Curitiba, which is considered as sub-tropical, presents a unique characteristic in Brazil being the coldest capital of all, making people feel some discomfort in more than 80% of hours of the year, from the thermal point of view, mainly for cold weather. A lot of field study was fulfilled, such as Nicol [5] and Humphreys [6], with the purpose of seeking an adaptable model of thermal comfort, based on the use of monthly average external temperature as a new parameter of comfort. The use of international parameters adapted to Brazilian regions, can reflect on a wrong way the real condition of thermal comfort. Other studies were fulfilled taking into consideration thermal ambient conditions and bioclimatic analysis through predicted equations Xavier [7], Kruguer[8] and also the studies of energetic thermal simulation program by Ghisi and Lamberts [9]. The present study insert itself in a wider work developed in 8 Brazilian cities with the purpose of studying and carrying out some information about office buildings placed in different regions of Brazil. Some information were collected through field study regarding office building placed in Curitiba city to get thermal energetic parameters linked to the local climate, providing, consequently, alternative for a better climatic adequacy for such buildings. Through the obtaining information concerning to the constructive type predominant in office buildings in the city we have defined a typed classification for the entire constructions surveyed. It has been also studied the energetic thermal performance of the surveyed constructions, being in possession of information concerning to temperature and humidity and of each type, through measurement made with the help of equipments designed to this task. METHODS For the obtaining information relating to office buildings type present in Curitiba, 841 constructions with more than 5 floors were surveyed, condition imposed for the fulfillment of a survey in buildings with elevator. To carry out architectural characteristics, responsible for the type formation, some visiting were given in 39 buildings, which of them were grouped in 21 different types, considering 5 variable architectural. For experimental limitations in a second step, it was considered only 3 architectural characteristics to the bioclimatic study of types. As a result of the steps 6 typologies were considered, which ones were compounded throughout the combination among the characteristics relating to the building height, the external shading presents and the window area versus front area. After separating the buildings in type groups, it was possible to carry out some information concerning to occupation standard of each office presents in each building representing one of the 6 typologies drew up. That way, it has been studied the activities performed in each building and it has got the relation of representative buildings in each one. For carrying out the thermal-ambient information, it was surveyed 6 representative buildings from the specific typologies. In each building it was installed equipments type HOBO H8 Family, to measure temperature and humidity in offices of a larger representative. Together with this equipment it has been used the software BoxCar Pro 4.0. The measurements were made considering the

3 proximity with the winter and summer solstice. It has been applied a questionnaire to people who occupy the offices for them to give their opinion regard to the comfort condition. After the measurement, it has been organized reports containing information relating to temperature changing and internal humidity of each office. Together with the external climatic information, it was made comparative tables of the internal thermal changing of the offices front to external thermal changing. With the use of software AnalysisBio developed by Energetic Efficiency Lab in Constructions at Santa Catarina Federal University LABEEE/UFSC, it has been made Psychometric charts, containing the bioclimatic zones proposed by Givoni [1]. Thus, such charts made possible the analysis relating to the thermal ambient performance of the buildings analyzed. This performance aims the thermal comfort with the minimum energetic consumption. Having such information made it possible to analyze the building performances in the summer and the winter months. RESULTS AND DISCUSSIONS The table 1 shows the representative architectural characteristics present in constructions analyzed. For the study of thermal performance it has been considered combination types of characteristics represented itself. Table 1- Architectural Characteristics Representative TYPES Nº BUILDINGS REPRESENTATIVITY Tall building 20 51,3% Low building 19 48,7% With external shading 14 35,9% No external shading 25 64,1% PWF > 50% 25 64,1% PWF < 50% 14 35,9% The table 2 presents the 6 typologies considered on the energetic thermal study. The separation of typologies took into consideration the height of buildings, the presence of external shading and percentage of window for front (PWF). Table 2 Type Considered At Thermal Energetic Analysis TYPOLOGY HEIGHT SHADING PRESENCE PWF 1 Tall With shading > 50% 2 Tall No shading > 50% 3 Tall No shading < 50% 4 Low With shading < 50% 5 Low No shading > 50% 6 Low No shading < 50% By the thermal ambient analysis in the summer the information reveal that, in all the typologies the results were inside the called comfort zone defined by Givoni [9]. The

4 bioclimatic study based itself on the analysis of proposed alternative at the bioclimatic chart made through the help of software AnalysisBio. The figure 1, presents the Bioclimatic Chart proposed by Givoni, it has already duly adequated for Curitiba City, where the rented points represent 8640 hours of the year allocated on itself. The climatic file of Curitiba used was TRY, determined for Curitiba by researchers of LabEEE [4], [10]. From these results it can be hoped that, part of the information placed itself inside the comfort zone (20,9%), some of them placed themselves into the hot region 2 and 11 (5,9%) and the rest of the points will fall down in 7,8 and 9 zones in need of some kind of heating. Zones: 1.Comfort 2.Ventilation 3.Evaporative cooling 4.Thermal mass for cooling 5.Artificial cooling 6.Humidification 7.Thermal mass for heating 8.Passive solar heating 9.Artificial heating 10.Ventilation/mass 11.Vent./mass/evap.cooling 12.Mass/Evap.cooling Figure 1 Psychometric Chart for the reference year of Curitiba City. Figure 2a Psychometric chart of type 3. Winter measurements.

5 The figures 2a, b e c show the bioclimatic results plotted on the psychrometric charts from 3 of the analyzed typologies. For making these charts it has been considered the temperature and humidity inside the whole offices places in this typology and it has been obtained the average of such measurements totaling 460 points. It has been plotted the information of typologies 3, 5 and 6 during the winter. For the summer almost all the interior points of the offices placed on the comfort zone. Figure 2b Psychometric chart of typology 5. Winter measurements Figure 2c Psychometric chart of type 6. Winter measurements. Analyzing the office thermal-ambient (see table 3), is has been concluded that, the typology 3 which has the following characteristics, tall building, no shading and with less than 50% of PWF, revealed the worst thermal performance in the winter days. And the typology 6 (low building, no shading, with less than 50% of window area by front area),revealed have the worst thermal performance relating to the summer days, obtaining an average temperature of 25,9 o C. But the typology 5 (low building, no shading, with more than 50% of window area versus front area) which one it had been hoped to have the worst result during the summer, due to its architectural characteristics, it has obtained 100% of the information inside the comfort zone in the summer and 96,8% in the winter.

6 Table 3 Typologies thermal Performance. TYPOLOGY SUMMER WINTER T med Humidity Comfort T med Humidity Comfort 1 24,0 60,1 % 100% 19,0 59,8 84,9% 2 24,9 59,7 % 100% 19,3 57,8 91,0% 3 24,0 55,1 % 100% 18,9 57,2 60,9% 4 25,5 59,8 % 99,6% 19,8 58,6 91,6% 5 25,8 56,1 % 100% 20,4 55,3 96,8% 6 25,9 57,2 % 98,4% 19,3 55,2 82,4% The figures 3a, b, c and d present the results of internal temperature variation comparing to external ambient temperatures, in the winter of 3 typologies during 15 days. Still analyzing the typology 3, it can be observed through graphs that its performance relating to great thermal variations showed itself relatively unwanted, because its thermal structure showed itself unable to absorb such variations in a satisfied way, showing a bad working of the envelope and its architectural characteristics. The typology 6 had a better performance and the 5 still better because even with colder external temperatures it has obtained 96,8% of the information inside the comfort zone. On the figure 3 it has been plotted together with the curve of the 3 typologies and the temperature of the external ambient in the winter. It has been seen that the typology 5 has obtained the major temperatures keeping the ambient always on the comfort zone; the temperatures of typology 3 has been the one that more accompanied the variation of external ambient. It can be observed through the questionnaire that, relating to the climatic conditions in the offices analyzed, the thermal feelings of the people inside the offices it has driven to a less wide ranging comfort band, being considered discomfort condition, temperature variation less than the stipulated limits on the bioclimatic comfort zone proposed by Givoni [1]. Internal Temperature Variation X External Temperature (Typology 3 - Winter) 27,0 24,0 21,0 ºC 18,0 15,0 12,0 9,0 8-jun 9-jun 10-jun 11-jun 12-jun 13-jun 14-jun 15-jun 16-jun 17-jun 18-jun 19-jun 20-jun 21-jun 22-jun 23-jun 24-jun 25-jun 26-jun Days External Temperature Internal Temperature Figure 3a: Internal temperature comparison front of external temperature variation relating to typology 3 (Winter).

7 Internal Temperature Variation X External Temperature (Typology 5 - Winter) 27,0 24,0 21,0 ºC 18,0 15,0 12,0 9,0 8-jun 9-jun 10-jun 11-jun 12-jun 13-jun 14-jun 15-jun 16-jun 17-jun 18-jun 19-jun 20-jun 21-jun 22-jun 23-jun 24-jun 25-jun 26-jun Days External Temperature Internal Temperature Figure 3b: Internal temperature comparison front of external temperature variation relating to typology 5 (Winter). Internal Temperature Variation X External Temperature (Typology 6 - Winter) 27,0 24,0 21,0 ºC 18,0 15,0 12,0 9,0 8-jun 9-jun 10-jun 11-jun 12-jun 13-jun 14-jun 15-jun 16-jun 17-jun 18-jun 19-jun 20-jun 21-jun 22-jun 23-jun 24-jun 25-jun 26-jun Days External Temperature Internal Temperature Figure 3c: Internal temperature comparison front of external temperature variation relating to typology 6 (Winter).

8 Temperature Measurement 27,0 External Typology 3 Typology 5 Typology 6 24,0 Temperature (ºC) 21,0 18,0 15,0 12,0 9, Days Figure 3d: Internal temperature comparison front of external temperature variation relating to typologies: 3, 5, 6 (Winter). CONCLUSIONS The present work has been consisted on carrying out 39 buildings representing a total of 841, placed in Curitiba city, thermal-ambient analysis measured in 6 buildings and to carry out the used standard of such ones. It has been concluded that the discomfort climatic conditions, for Curitiba city, are predominantly caused for cold weather, as it was hoped. During the winter it was obtained better results for the typology 5 (low building, no external shading and with the percentage of window for front larger than 50%, having almost all the information placed inside the comfort zone. During the summer the comfort conditions of the various typologies were alike. It must be still considered the difficulties found on the survey development. With the methodology used based on field analysis, the information collect was subjected to a several limitations. Such limitations have involved difficulties on the information collect and the lack of reasonable time for studying and analyzing of the software used in this survey. This way, due to a temporal limitation to what the present work was subjected, we have suggested a large information collect to take into account some more typology considerations, such as kind of glass and window open, color and the front guidelines. It has been also recommended to make computerized study using a simulations analysis program.

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