Celina Filippín

Thermal behavior of building walls in summer: Comparison of available analytical methods and experimental results for a case study

There is a wide variety of thermal analyses that can be used to characterize the thermal behavior of a wall under certain outdoor conditions. The selection of a particular wall configuration for a building project involves not only the outdoor climate, but also the whole building characteristics, orientation, percentage of glazed areas, occupation periods, lifestyles, etc. In this paper we apply common available methods for wall thermal analysis to two particular wall types, a massive brick wall and an insulated brick wall, in order to compare the information given by each method and to evaluate how these methods can help in the selection of a certain type of wall. The studied methods include the estimation of the wall time lag and decrement factor, the harmonically heated slab model, the Athanassouli’s method, and numerical simulations. The study was performed for the walls of a residence for university students and it was built in La Pampa (Argentina). Once the building was finished, the transient thermal behavior of two walls was monitored during one summer week. The experimental results are presented and the fitting with the thermal behavior predicted by each method is discussed. The thermal comfort indicators PMV (predicted mean vote) and PPD (predicted percentage of dissatisfied) were calculated for two flats, at ground floor and first floor respectively.

An Energy Efficient School for A Nature Disposed Population in Arid Lands of Central Argentina

The monitoring and simulated thermal behavior of a passive solar school at the Northwest of La Pampa province (Argentina) and the results of social-environmental surveys are presented. The passive design strategies are direct solar gain, thermal mass, insulated building envelope, daylighting, and natural ventilation. The monitoring is carried out under normal conditions of use (with the heaters working because of students attendance) and during an unoccupied period in winter holidays. The transient thermal simulation is carried out with SIMEDIF for Windows, a software developed at INENCO (Non Conventional Energy Research Institute) and widely used by researchers of Argentina. Northern glazed areas, orientation, internal heat gains, and use of the heating system, are analyzed. The daily heating energy consumption is 0.009 m3/m2 of the building’s useful area. When compared to conventional schools, 90% of heating energy savings are noticed. The surveys show that a predicted percentage of dissatisfied (PPD) is around 5, with mean temperature and relative humidity around 17 C and 27%, 1.6 clo (with jacket), and 1.8 met of metabolic rate (1 met = 58 W/m2). Therefore, ISO 7730 standards are satisfactorily accomplished.

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.

Analysis and Improvement of the Thermal Behavior of Social Houses in Northern Argentina Through Transient Thermal Simulation

The analysis of the winter and summer thermal behavior of a low-income dwelling, built by Provincial Institute of Dwelling in Salta, is presented. For both orientations of the major axis, the mean indoor temperatures in winter were around 14°C with a daily thermal swing between 5°C and 10°C, values that are outside the comfort area. Thus, auxiliary conventional heating is needed during all the day. In summer, the dwellings are almost all the day outside the comfort area, with indoor temperatures higher than outdoor air and thermal swings between 7°C and 10°C. Clearly there is a lack of storage mass to moderate the internal air swing. A set of alternatives to improve the indoor thermal comfort was ana- lyzed. The program SIMEDIF for Windows was used to simulate the hourly thermal behavior of the dwelling.

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.

The Comprehensive Comparison of Thermal and Physical-Mechanical Properties of the Recycled Rubber and Plastic Roofing Tiles versus Roofing Tiles Made with Different Traditional Materials

The objectives of this research were to estimate the thermal transmittance and some physical-mechanical properties of a housing cover built with roofing tiles made from recycled plastics and rubber and compare them with three other traditional solutions for housing cover: ceramic roofing tiles, concrete roofing tiles, and zinc sheets. This roofing tile has technical advantages over the others, due to its higher thermal insulation, higher resistance to freezing, higher resistance to hail, higher flexural resistance, lower specific weight, and lower water absorption, with lower cost than the traditional glazed black ceramic roofing tile. And it is also friendlier to the environment.