Simulation of the thermal performance of low cost houses in Venezuela to improve thermal comfort

GEOVANNI SIEM

Universidad Central de Venezuela. Facultad de Arquitectura y Urbanismo, Instituto de Desarrollo Experimental de la Construcción. e-mail: geovanni.siem@gmail.com

ABSTRACT

This work aims to investigate the thermal behaviour of low cost houses widespread in many regions in Venezuela and discuss their suitability to climatic conditions, aided by ArchiPak™, a simulation software developed by Dr. Steven Szokolay. The simulation conditions correspond to three important cities located at different altitudes: Caracas (880 m), Maracaibo (40 m) and Mérida (1500 m). Frequently the occupants complain of low thermal comfort, especially in the warmhumid climate which prevails in most of the cities and populated areas. As a solution the owners undergo some modifications based on installing air conditioning equipment which is accompanied with additional energy consumption and maintenance costs. The results showed that the inside temperature at low altitudes is very high and houses are uncomfortable the whole year. At mid and high altitude the temperatures are close to the comfort zones and it is possible to improve their performance with appropriate design strategies. The modifications include solar protection in windows and a good orientation improve thermal behavior to a small degree: hence, it is necessary to use these together with other solutions focused on using materials in walls and roofs with more appropriate thermal properties to produce significant improvements.

Keywords: Low cost housing, Comfort, Energy, Simulation, Hot humid climate.

Simulación del comportamiento térmico de viviendas de bajo costo en Venezuela para mejorar el confort térmico

RESUMEN

Este trabajo tiene como objetivo estudiar el comportamiento térmico de viviendas de bajo costo construidas en varias regiones de Venezuela, y discutir su adaptabilidad a las condiciones climáticas. Para ello se realizaron simulaciones en tres importantes ciudades localizadas a diferentes altitudes: Caracas (880 m), Maracaibo (40 m) y Mérida (1500 m), con la ayuda del programa ArchiPak™ desarrollado por el Dr. Steven Szokolay. Con frecuencia los ocupantes de estas viviendas se quejan del bajo nivel de confort térmico, especialmente en las zonas de clima cálido-húmedo, el cual prevalece en las ciudades y regiones más habitadas de Venezuela. Como solución los propietarios realizan modificaciones basadas en la instalación de equipos de aire acondicionado la cual está acompañada de costos adicionales de adquisición y mantenimiento de los equipos, así como también de consumo de energía, que contradice el concepto de vivienda de bajo costo y que además conspira contra la calidad ambiental. Los resultados muestran que a baja altitud la temperatura interior está por encima de la zona de confort casi todo el año. En medias y grandes altitudes la temperatura interior está bastante cerca de la zona de confort y es posible mejorar su comportamiento con estrategias de diseño apropiadas. Las modificaciones que incluyen protección solar en ventanas y una buena orientación mejoran la calidad térmica en cierta medida, y son complementadas favorablemente por el uso de ventilación natural con 1 y 1,5 m/s. En conclusión, la calidad térmica de estas viviendas se puede mejorar con el uso de técnicas pasivas de refrescamiento, pero es necesario profundizar el estudio acerca del uso de materiales en techos y paredes con propiedades térmicas más apropiadas para cada zona climática.

Palabras clave: Viviendas de bajo costo, Confort térmico, Energía, Simulación, Clima cálido-húmedo.

Recibido: mayo de 2007 Revisado: noviembre de 2007

INTRODUCTION

A very important part of the Venezuelan population lives near the Caribbean coast where the climate is warm and humid almost the whole year. Because poor people represent a very important percentage of the total population (about 26 million), the government traditionally have provided economical and technical support to them through dwellingprograms based on low interest loans. The INAVI (NationalHousing Institute) has been in charge of designing andbuilding these dwellings based on economical criteria; hencequality is second class, especially thermal comfort, acousticsand lighting. Frequently the occupants modify the originaldesign in order to improve their performance, and one of themost common solutions is installing air conditioningequipment. Its design is very simple and it is built with materials and components easily found in local stores. The house chosen in this study (INAVI, 2001) has the same specifications as any location, without taking into accountthe climatic differences as a result of altitude. In this work a simulation tool is used to study thermal performance with passive cooling of a low cost houses in three importantcities located in different climatic zones and to discuss the best solutions to improve the thermal comfort of the occupants. This work is part of wider research carried out by the author (Sosa and Siem 2004, 2005) on building thermal performance in different climatic zones in Venezuela that includes multistorey residential and commercial buildings. It is also an approach towards a design guide for low cost passive houses in Venezuela, based on the climatic characteristics of each zone and it could be an important contribution to fulfill the lack of standard of thermal performance (ENELVEN, 2005). Venezuela has been characterized by the bad habits of energy consumption in the population, because of the availability and low cost of energy resources (oil, gas and hydroelectric power). A change in the thermal performance of this house will have an impact in the population in many ways: thermal comfort, economical and energy saving.

METHODOLOGY

This study is based on simulations of a low cost house, with the original specifications of design defined by the INAVI, known by the name Chaguaramas, in August, the warmest month in Venezuela. The climatological data correspond to three important cities of Venezuela, located in climatic zones identified by their altitude: Caracas (1000 m), Maracaibo (40 m) and Merida (1500 m). The house’s main façade which has the greatest opening surface wasoriented north. Based on these results and in function of the passive cooling strategies pointed out by thepsychrometric chart, some measures related to the shadingon windows and the roof components were taken to improvethe house’s thermal performance. The results were analyzedto evaluate the impact of these improvements in relation tothe thermal comfort of the occupants and the potentialsaving of energy, in case that active cooling is used. These results were also useful to estimate the adaptability from this design to each climatic zone included in this study. Simulations were done with ArchiPak version 5.4, software developed by the Dr. Steven Szokolay, which presents important advantages because of its friendliness and complete database information.

VENEZUELAN CLIMATE

Venezuela is located between 1° and 13° north latitude, with a varied geography that includes coasts, flat lands, high savannas and mountains that reach near 5,000 m of altitude.Although Venezuela lies wholly within the tropics, its climatevaries from tropical humid to alpine, depending on theelevation, topography, and the direction and intensity ofprevailing winds. Seasonal variations are marked less bytemperature than by rainfall. Several climatic classifications have been developed based on different approaches thathave taken into account some factors such as water masses, rainfall, vegetable basement and topography. The classification proposed by Koppen (Hobaica et al. 2002)tries to gather all the factors, constituting an exhaustive division that considers diverse climate types: rainy tropical forest, savanna, semi-arid, height tropical, height rainy and perennial snow. A classification carried out in the CentralUniversity of Venezuela by Hobaica (Sosa and Siem, 2004) is focused in urban areas, where the microclimate isinfluenced by the builtup environment. The climatic zones were demarcated on the basis of the air temperature that isthe variable that changes most throughout the Venezuelan geography; because solar radiation and humidity vary little. This fact is justified because most of the Venezuelan population (near 90%) lives in cities whose altitude varies from sea level to 1000 m, while 10% of them live between 1000 and 3000 m. The zone classification made by Hobaica was based on the meteorological data of 29 stations contained in the publications of the Meteorology Serviceof the Venezuela Defense Ministry. This macro-classificationis the first approach to define design recommendations adapted to the climate and to suggest more efficient systems of environmental control from an energy efficiency point of view (Table 1).

Figure 1. Climatic zones in Venezuela. 

Table 1. Classification of climatic zones in Venezuela.

METEOROLOGICAL DATA

The meteorological information used in this work has been obtained from the Meteorological Service of the Venezuelan Air Force. This data corresponding to year 2001, include hourly measures of maximum and minimum temperatures; relative humidity; wind speed and direction; global, direct and diffuse irradiation.

PASSIVE COOLING POTENTIAL

During the first steps of building design it is necessary forthe participants of the project to choose a cooling technique that ensures a sufficient degree of comfort and to evaluatethe energy consumption and the energy gain due to the use of a passive cooling technique. Several methods offer moreor less precise information about thermal building behaviorand the evaluation of buildings equipped with passivecooling systems. Givoni and Szokolay developed a method to define from the Psychrometric chart areas of comfort infunction of different passive cooling strategies.

This approach provides useful qualitative information forarchitects and building designers on the feasibility of a passive cooling technique based on comfort aspects. Nevertheless, it is necessary to quantify the potential of each cooling technique and to calculate the energy gain achieved by using a passive cooling system. In previous works (Belarbi and Allard, 2001; Hobaica et al. 2002) simulations aimed to evaluate the climatic potential of someof passive cooling techniques were made as a way for setting down the basis for their application in accordance with Venezuela’s varied climate. The first estimates providedpromising results in order to complement design strategies for obtaining suitable levels of comfort while reducingenergy spending. The methodology used in these works follows a simplified procedure based on valuation indexes developed by the University of La Rochelle in the framework of the European projects Pascool/Joule and Altener/Sink. This procedure gives the necessary information for developing design tools that could be used to improve indoorcomfort at reasonable energy costs. For each studied passivecooling system, it is possible to define evaluator factorswhich characterize the climate conditions, the nature of thetechnique, potential of the sink and the building type. Thesefactors allow comparison of the different passive coolingtechniques potential. Knowing the characteristics of theused fluid properties and of the natural source of cooling,called the sink, evaluator indexes dealing with the coolingpotential of passive systems could be defined. For passivecooling systems which operate with the same air mass flowrate and the same fluid (air), an index is defined, IPTheoretical,of comparison of the theoretical potential that depends only on the sink by TSink(t) and the climate of the site by TInlet(t),IPTheoretical = [TInlet(t) - Tsink(t)]dt measured in degreehours (°h). The simulation results (Hobaica et al. 2002) the potentials of passive cooling in six Venezuelan cities located in different climatic zones were estimated based on degreehours calculation as a complementary approach of thermalbuilding evaluation. They were considered respectively, a temperature of design of 25 ºC and a relative humidity of 75%. These results are related to a line of research at the Central University of Venezuela, which aims to explore the possibilities of the use of different cooling strategies to create an Atlas of Passive Cooling Strategies that serves as guide for architects, engineers and builders when making design decisions. In that work strategies of direct and indirect evaporation, radiant cooling and buried tubes were explored and their potential were calculated as shown in Figure 2.

Figure 2. Covering of passive cooling potential in Venezuelan cities. Source: (Hobaica, Allard, Belarbi, Rosales, 2002)

This information helps us search for the most appropriate strategies for each climatic zone and to deepen the search of appropriate solutions to each climatic condition. When analyzing these results it is possible to verify thatconcerning the systems of buried tubes and radiative coolinga total covering is possible for Caracas, Maracaibo andMérida, while the evaporative cooling strategy is notappropriate for Maracaibo. The main aim of this paper is to fine tune this study by applying the theory to specific cases.

BUILDING DATA

The Chaguaramas House, shown in Figure 3, is one of the most popular houses built by INAVI (Housing National Institute) because of its dimension and cost. It has beendesigned with the minima requirements that accomplish the national housing system. It has the necessary space for afamily of five. It has a parking area and a garden to the front, and to the bottom a courtyard where the housing can growin horizontal form in the future according to needs andpossibilities. Other data are: total land area: 200 m² (10 mx20m); house area: 68 m² approximately; steel structural system;walls: hollow bricks of 20 x 30 x 10 cm; floors: slab on ground;windows: metal frame, single clear 6 mm glass; doors: metal frame, inset panels; pitched roof: tiles, asphalt, timber deck 1½ cm.

Figure 3. Chaguaramas House: isometric and plane view. Source: (INAVI, 2002)

SIMULATION CONDITIONS

Simulations were running for a complete year (2001) based in the data from the Venezuelan Air Forces. The house wasoriented with the main façade to the North. Facades northand south have the largest window surface. The data of thematerials and components were obtained from the technicalspecifications which appeared in the INAVI officialdocuments. Other information is: 5 family members, interiorvolume of 154 m3, rate of 3 air change per hour, a gain ofinternal heat estimated in 300 w. The warmest month inVenezuela (August) was chosen to compare the results ofthe three cities. In each city two case studies were also defined: original components and improved proposal; whose  properties appear in Table 2.

Table 2. Building data.

STUDIED CITIES

Three cities have been selected in this study, located at different altitudes in order to obtain a wide spectrum of results that allow extrapolation to other cities of the country. These are: Caracas, capital of Venezuela, 4.5 millioninhabitants, 880 - 1000 m altitude; Maracaibo, second city,center of the oil industry, 2.0 Million inhabitants, 40 maltitude; Merida, city located in the mountain chain of The Andes, important university and tourist center, 300,000 inhabitants, 1500 - 1700 m altitude. The 2001 climatic data are shown in Tables 3, 4 and 5.

Table 3. Climatic data for Caracas.

Table 4. Climatic data for Maracaibo.

Table 5. Climatic data for Merida.

RESULTS

The psychometric diagram allows us to study the relationship between the climate of each one of the cities,the comfort zones and the potentials of passive cooling strategies. The results obtained from ArchiPak can be analyzed in Figures 3 to 5.

Results for Caracas

The Mahoney Tables obtained from ArchiPak offer the following design recommendations to Caracas: orientation north-south (long axis east-west), compact estate layout,no cross ventilation required, large opening sizes: 50-80% of wall surfaces, full permanent shading, rain protectionrequired, lightweight walls and floors construction: of lowthermal capacity, lightweight roof construction: well insulated, adequate rainwater drainage is important. ArchiPak use the Control Potential Zone (CPZ) method to show in the Psychrometric chart the relationship betweenclimate and passive cooling strategies to building design. According to Figure 5, the temperatures in Caracas are below the upper limit of comfort temperature (Tu) almost the whole year. The same figure shows the possibilities of employing the cooling effect of the air movement to improve the thermal comfort if necessary. Simulations made with the original conditions and animproved version based on a shading coefficient of 0.3 anda proposal solution to the roof with a reflecting foil and abetter insulation, are shown in Figure 4. According to theseresults the maximum temperature reached in the originalhouse (37.9 °C) is too high in comparison to the comforttemperature (27.25 °C), but in the improved version the maximum temperature is 32.1 °C which is very close to the extended limit of comfort temperature with an air movement of 1.5 m/s (32.35 °C) shown in Table 6.

Figure 4. Temperatures profiles for the original house and an improved version in Caracas.

Figure 5. CPZ for the cooling effect of the air movement in Caracas.

Table 6. Annual temperatures for Caracas.

A comparison of the annual load requirements in Caracas between the original house and the improved version is found in Table 6. The potentiality of energy saving (kWh) is 65% in controlled mode and a reduction of 65% K.h in freerunning mode.

Table 7. Annual load requirements for Caracas.

Results for Maracaibo

The Mahoney Tables obtained from ArchiPak offer the following design recommendations for Maracaibo:orientation north-south (long axis east-west), open spacingto allow for breezes, single banked rooms for full crossventilation,large opening sizes: 50-80% of wall surfaces,opening in N and S walls: body level on windward side, fullpermanent shading, light weight walls and floors construction: of low thermal capacity, light roof construction: reflective surface and cavity between roof and ceiling. According to the Figure 7, the temperatures in Maracaibo are always above the upper limit of comforttemperature (Tu). The same figure shows the possibilitiesof employing the cooling effect of the air movement toimprove the thermal comfort as the main design strategy.

Figure 6. Temperatures profiles for the original house and an improved version in Maracaibo.

Figure 7. CPZ for the cooling effect of the air movement in Maracaibo.

Simulations made with the original conditions and animproved version in Maracaibo are shown in Figure 6.  According to these results the maximum temperature reached in the original house is 43.6 °C and in the improved version is 37.8 °C. Both of them are far from the extended limit of comfort temperature with an air movement of 1.5 m/s (34.27°C) shown in Table 8. It means that a further research isneeded to consider new materials and components, important changes in design and finally, an active or hybrid cooling system.

Table 8. Annual temperatures for Maracaibo.

A comparison of the annual load requirements in Maracaibo between the original house and the improved version is found in Table 9. The potentiality of energy saving (kWh) is 29% in controlled mode and a reduction of 26% K.h in freerunning mode.

Table 9. Annual load requirements for Maracaibo.

Results for Mérida

The Mahoney Tables obtained from ArchiPak offer the following design recommendations for Mérida: orientationnorth-south (long axis east-west), compact estate layout,no cross ventilation is required, opening sizes: medium 30- 50% of wall surface, full permanent shading, walls and floors construction: heavy over 8 hours time-lag, roof construction: lightweight, well insulated, adequate rainwater drainage. According to the Figure 9, the temperatures in Mérida arealways below the upper limit of comfort temperature (Tu).The same figure shows the possibilities of employing thecooling effect of the air movement to improve the thermal comfort if necessary.

Simulations made with the original conditions and an improved version in Mérida are shown in Figure 8. According to these results the maximum temperature reachedin the original house is 34.2 °C and in the improved versionis 29.0 °C, which is below the extended limit of comforttemperature with an air movement of 1 m/s (30.52 °C) shown in Table 10. It means that it is quite easy to get the comfort zone with little changes.

Table 10. Annual temperatures for Mérida.

A comparison of the annual load requirements in Mérida between the original house and the improved version is found in Table 11. The potentiality of energy saving (kWh) is 64% in controlled mode and a reduction of 80% K.h in free-running mode.

Figure 8. Temperatures profiles for the original house and an improved version in Mérida.

Figure 9. CPZ for the cooling effect of the air movement in Mérida.

Table 11. Annual load requirements for Mérida.

DISCUSSION

Analyzing the results corresponding to the three cities it’s possible to appreciate big differences in potentialities for passive cooling. This remark reinforces the observationabout the inadequacy of the same house design for different climatic zones in Venezuela. It is interesting to observe thatthe temperature in Merida stays below the temperature limitof the comfort zone 55% of the time, while Maracaibo neverreaches temperatures below this same limit which is ameasure of potentiality of using passive cooling techniques for improving the thermal performance.

Reviewing the curves of temperature in August, it could be noticed that in Caracas the Ti.max is 37.9 °C and that it decreases at 35°C, a reduction of 2.9°C, applying a shadingfactor of 0.3. In the case of Maracaibo these values are 42.9°C and 40 °C, a reduction of 2.9 °C. In the case of Merida, thevalues are 33.7 and 31.7, a reduction of 2 °C. As a conclusionit could be said that applying other more appropriatestrategies to each climatic region could achieve a betterthermal behavior by these houses and to offer the comfortrequired to their occupants. It should take into account that this will be achieved in a simpler way in the case of Meridaand also in Caracas because the climatic conditions would allow it. In the case of Maracaibo the solutions are morecomplex because the high values of temperature and humidityrestrict the application of passive cooling; the most suitable solution according to the psychometric diagram is increasing the natural or mechanical ventilation. It would be necessaryto also consider the use of the active-passive hybrid cooling. Concerning the annual load requirements for cooling isnoticeable that Maracaibo has very high values in bothcases: 11626 kW (original) and 8304 kW (improved), whichrepresent an important issue to the energy saving plans. Aspresented by the simulations it is very difficult to reach thecomfort zone even with air movement. The big differencesrelated to the results obtained for Caracas (4022 and 1397kW) and Mérida (1158 and 415 kW), where it is possible to get the comfort zone almost the whole year, show the inadequacy of this design in the low altitudes zones. It is important to remark that the majority of the Venezuelan population lives in this zone.

CONCLUSIONS

The results of the simulations allow the inference that the thermal performance of the Chaguaramas House is different in each climatic zone considered in this study; hence it hasa different level of architectural adaptability to the climaticconditions. The temperatures reached in the original versionare too high in the three climatic zones included in this studyand they are above the comfort temperature during thewarmest month (August). The improved version offer an appropriate level of thermal comfort to the occupants that live in areas located in high altitude like the city of Merida(1500 m). In the case of Caracas, which is in a middle altitude (880 m), comfort is achieved during the coldest months(November, December, January, February) and almostcompletely in the warm months (June, July, August). In the case of Maracaibo (40 m), comfort is not achieved during any time of the year. The main problem comes from the climatic conditions because the very high readings of temperature and humidity allow the use of few strategies. The ventilation is an important help in this case, hence a good solution could be a combination of new materials andcomponents for walls and roofs that improve the thermalbehavior of the housing, and the use of the natural andmechanical ventilation. It should be explored in anotherinvestigation, to take additional measures that could changethe design of the house, that which was not in the objectivesof this work. Among these measures it can be considered:to use more appropriate materials to warm climate in walls and roofs, to increase the window area to favor theventilation, to modify the basic design and to proposespecific solutions according to the orientation, to usemechanic ventilation if the area where the housing is located doesn’t have air currents. These first results confirm the initial assumption concerning the inadequacy of this design and they allow to tune the next works on dwellings and multistory residential buildings.

ACKNOWLEDGEMENT

The author wishes to thank the Consejo de Desarrollo Científico y Humanístico de la Universidad Central de Venezuela for its financial support to my PhD study, theDirector of The Centre for Sustainable Design of the University of Queensland, Associate Professor RichardHyde, for his important support and guidance in thisresearch, and Dr Steven V. Szokolay, Honorary Associate Professor of Architecture, University of Queensland, for helping and supporting him while he was learning ArchiPak.

REFERENCES

1. AHMAD S. S. (2004). A study on comfort conditions and energy performance of urban multistorey residentialbuildings in Malaysia, PhD Thesis, The University of Queensland: Australia.        [ Links ]

2. ALLARD, F., HOBAICA, M.E. AND BELARBI, R. (2000). Tratamiento térmico de la Edificación en el Trópico Ecuatorial hacia la Reducción del Gasto Energético, Memorias del Primer Simposio Venezolano de Confort Térmico y Comportamiento de Edificaciones COTEDI’98, COTEDI 2000, Maracaibo, Venezuela.        [ Links ]

3. ALLARD, F. AND BELARBI, R. (1998). Metodología de evaluación de las técnicas pasivas de enfriamiento, COTEDI’98: Caracas.        [ Links ]

4. ANSARI, F.A., MOKHTAR, A.S., ABBAS, K.A. AND ADAM, N.M. (2005). A Simple Approach for Building Cooling Load Estimation. (Malasya) American Journal of Environmental Sciences 1 (3): 209-212, Science Publications.        [ Links ]

5. BARBOSA, M. J. (1997). Uma metodologia para especificar e avaliar o desempenho térmico de edificações residenciais Unifamiliares, PhD Thesis: Universidade Federal de Santa Catarina, Brasil.        [ Links ]

6. BELARBI, R. AND ALLARD, F. (2001). Development of feasibility approaches for studying the behavior of passive cooling systems in buildings, Renewable Energy 22 507– 524: Brighton, UK.        [ Links ]

7. ENELVEN CENTRO DE OPTIMIZACIÓN ENERGÉTICA. (2005). Ordenanza sobre Calidad Térmica en Edificacionesen el Municipio Maracaibo, C.A. Energía Eléctrica de Venezuela: Maracaibo, Venezuela.        [ Links ]

8. GERMANO, M., ROULET, C.A., ALLARD, F. AND GHIAUS, C. Potential for natural ventilation in urban context : an assessment method AIVC 23rd conference - EPIC 2002AIVC (in conjunction with 3rd European Conference on Energy Performance and Indoor Climate in Buildings) vol 2, pp 519-524: Lyon, France.        [ Links ]

9. GHIAUS, C. AND ALLARD, F. (2006). Potential for free-cooling by ventilation, Solar Energy 80 402–413: University of South Florida, Tampa FL, USA.        [ Links ]

10. GHIAUS, C. AND ALLARD, F. (2003). Statistical interpretation of the results of building simulation and its use in design decisions, Building Simulation’03 Conference: Eindhoven, The Netherlands.        [ Links ]

11. GHIAUS, C. AND ALLARD, F. (2002). Assessment of natural ventilation potential of a region using degree-hours estimated on global weather data AIVC 23rd conference - EPIC 2002 AIVC (in conjunction with 3rd European Conference on Energy Performance and Indoor Climate in Buildings): Lyon, France.        [ Links ]

12. HOBAICA, M.E., ALLARD, F., BELARBI, R. AND ROSALES, L. (2002). Passive cooling techniques for buildings. Potential of use within venezuela’s climatic zones, AIVC 23rd conference - EPIC 2002 AIVC (in conjunction with 3rd European Conference on Energy Performance and Indoor Climate in Buildings): Lyon, France.        [ Links ]

13. HOBAICA, M.E., BELARBI, R. AND ROSALES, L. (2001). Los sistemas pasivos de refrescamiento de edificaciones en clima tropical húmedo. Posibilidades de aplicación en Venezuela Tecnología y Construcción Vol. 17-1 pp. 57-68: Caracas.        [ Links ]

14. HOBAICA, M. E., SOSA, M. AND ROSALES, L. (2000). Influencia de los componentes constructivos en la temperatura del aire interior de viviendas, Interciencia Vol. 25 N° 3: Caracas, Venezuela.        [ Links ]

15. Instituto Nacional de la Vivienda - INAVI. (2001). Tipologías de Viviendas: Caracas, Venezuela.        [ Links ]

16. HYDE, R. (2000). Climate Responsive Design, E & FN Spon: New York.        [ Links ]

17. KOENIGSBERG, INGERSOLL, MAYHEW, SZOKOLAY, S. (1977). Viviendas y Edificios en Zonas Tropicales Paraninfo S.A.: Madrid.        [ Links ]

18. SOSA, M. E. AND SIEM, G. (2004). Manual de Diseño para Edificaciones Energéticamente Eficientes en el Trópico. IDEC FAU UCV, C.A La Electricidad de Caracas: Caracas.        [ Links ]

19. SOSA, M. E. AND SIEM, G. (2005). Criterios de Diseño para Edificaciones Energéticamente Eficientes en Venezuela Revista de la Facultad de Ingeniería FI UCV, Vol 19 -N 3, Pag 21: Caracas.        [ Links ]

20. SZOKOLAY, S. (2004). Introduction to architectural science: the basis of sustainable design Architectural Press: Oxford.        [ Links ]