Alfredo Esteves

Comportamiento termico-energético de una vivienda social de la ciudad de Mendoza, Argentina

The state provides 30% of houses per year in the city of Mendoza. This study evaluates: (a) the thermal-energy quality of a social house, through in-situ measurements under conditions of actual use; (b) needed energy requirements through a balance; (c) a simulation of the house using the SIMEDIF program, in which the model was adjusted, and some easy to implement and economical improvements were tested; and (d) a qualitative survey of thermal sensations. The results indicated that the building has a deficit in its thermal and energy efficiency: real energy consumption is lower than the results obtained by calculation. This is presumably because the user is unable to bear the financial cost of the energy consumption that would keep the house in a comfort situation. Improvements in the thermal quality of the envelope, which were considered in the simulation, result in 35.6% of energy savings and the achievement of comfort conditions in the housing spaces.

Efecto de la ventilación natural en el consumo energético de un edificio bioclimático. Análisis y estudio mediante energy plus

espanolEl enfriamiento pasivo a traves de la ventilacion natural presenta un gran potencial para viviendas unifamiliares en climas templados continentales como lo es el de la ciudad de Mendoza, ubicada al centro oeste de la Republica Argentina. Esta estrategia persigue evitar riesgos de sobrecalentamiento y reducir la necesidad de uso de los equipos mecanicos. El objetivo del estudio expuesto es evaluar la influencia de la ventilacion natural diurna y nocturna en el consumo de energia en condiciones reales de uso de una vivienda con construccion tradicional y construccion industrializada. Para ello, se uso un modelo computacional de una vivienda unifamiliar, modelada y ajustada en el programa Energy Plus v8.6. Y, para el modelado de la ventilacion natural, se utilizo “Airflow Network” (algoritmo AIRNET), validado por Gu (2007) y Crawley et al. (2001). Los resultados indican que, tanto en la construccion masica como en la liviana, con ventilacion nocturna, los consumos energeticos son menores en 50% que ventilando de dia. La ventilacion natural en edificios bioclimaticos resulta una estrategia indispensable para el enfriamiento del mismo. En esta situacion radica la importancia de contar con una herramienta de simulacion para el ensayo de diferentes modos de uso y control de la misma. EnglishPassive cooling through natural ventilation has a great potential for single-family homes and temperate continents such as the city of Mendoza, located in the central west of the Argentine Republic. This strategy seeks to end the risks of overheating and reduces the energy consumption of mechanical conditioning equipment. This study aims to evaluate the influence on energy consumption, in two ventilation scenarios (day and night) for two constructive resolutions (light and mass). For this, a computational model of a single-family house, modeled and adjusted in the Energy Plus v8.6 program was used. For the ventilation model, “Airflow Network” (AIRNET algorithm) validated by Gu (2007) y Crawley et al. (2001) was used. The results indicate that, in the construction as well as in life, with night ventilation the energy consumptions are lower in 50% than they ventilate during the day. The natural ventilation in bioclimatic buildings is an indispensable strategy for the cooling of the same. In this situation lies the importance of having a simulation tool to test different scenarios of use and control of the same.

Positioning and Design Recommendations for Materials of Efficient Thermal Storage Mass in Passive Buildings

The amount of energy storage strongly depends on the position, material and it thickness. In this paper, the geometric and energetic positioning of thermal mass has been studied in order to determine the most convenient locations. Following this, 14 cases representing different positions of windows within facades facing the Equator are analyzed. These cases are studied with a model that estimates direct solar radiation that crosses through the window and is absorbed in various surfaces within the room. All cases show that 70% to 90% of the direct daily solar radiation that is transmitted by vertical windows impact the floor during the most energetic hours (from 9am to 3pm – solar time). East or Sest facades receive only 0% to 13% depending on whether the window is near the side East or West of the facade. The southern wall receives up to 10% of daily direct solar radiation depending on the depth of the room and the height of the window. Optimal thicknesses of storage materials are studied through the diurnal heat capacity (dhc), which also depends on the material and solar insolation of the elements. If it is sunny, optimal thickness and dhc are: 0.20 m and 266.1 kJ/m2.°C for granite; 0,20 and 247.3 kJ/m2.°C for concrete; 0,15 m and 224 kJ/m2.°C for paver brick and for hardwood 0,075 m and 49.8 kJ/m2.°C. In remote areas that do not receive direct sunlight, the optimum thickness of walls is reduced to 0,075 m with dhc approximately 30% of the dhc in sunny thermal mass. Therefore, in those spaces with direct gain or greenhouses, a thickness of 0.20 m of granitic or 0.15 m of cement floor and 0,075 m for walls should be used. In remote areas, a thickness of 0,075m for any floor or wall should be used. Wood is not recommended given the low dhc value for the usual thickness used in buildings (only 19,7 kJ/m2.°C for 0,025 m).

Solar oven with downward and upward solar gain for children’s dining rooms in developing countries

ABSTRACTIn Argentina there exist children’s dining rooms where infants and their mothers take lunch at noon and glasses of milk in the afternoon. These dining rooms are established in rural or marginal urban areas. Solar ovens are an interesting option for cooking with less expense of money, and they diminish environmental impact in these zones. A solar oven with downward and upward solar gain was built and tested. Upward solar gain is through Fresnel reflectors. The use of Fresnel reflectors resulted in higher heating power as compared to a solar oven with upper reflectors only. The performance with different numbers of Fresnel units was compared with a single-reflector solar oven with no lower Fresnel reflectors. Oven power was analysed and the result indicates that power grows as the number of Fresnel reflectors increases: it grows by 55% using 3 to 9 Fresnel reflectors, and by 34.6% with 3 to 6 Fresnel reflectors. These values are enough to cook several rations of food, and make this oven appropriate ...

Energy Efficient School Buildings in Central-Western Argentina an Assessment of Alternative Typologies for the Classroom Tier

Publisher Summary Four energy-efficient demonstration school buildings are built in the western province of Mendoza, Argentina, as a part of a massive building program required to implement the new Federal Education Plan. The buildings make the maximum use of bioclimatic strategies and daylighting. It is noted that the aspects of typology of the classroom tiers became immediately apparent as one of the main conditioners of the overall scheme. Three different alternative schemes are essentially designed and built. Four typologies of the classroom tier using the same, locally available technology, are being assessed in the aspects of energy efficiently, thermal and luminous comfort, construction and operation costs, and environmental impact. The chapter presents the provisional results of the first two items—namely, the energy efficiency and the thermal comfort.