Estudo de desempenho do aquecedor solar de baixo custo

Abstract

One alternative to reduce consumption of electric energy to heat water will be popularize the use of solar energy. This work comes to contribute of studies about the Low Cost Solar Heater , ASBC, which is a new concept of solar water heater for home, all made by polymeric materials with relatively small investment and can be built manually. The plate of the collector, which absorbs solar energy and transfers to the water in the form of heat, is composed of rigid PVC plans profiles and without coverage. Another option of solar collector which was used is a plate of polypropylene, a material with anti-UV additive, as well as the plate of PVC thermal performance was analyzed in this work. The thermal reservoir of each one the two collectors is polyethylene coated on polystyrene, which is responsible for storing the heated water during the day. Both heating systems had their results compared with the conventional heater, consisting of collector of copper covered by a cover glass and a stainless steel tank. A bench of tests for solar collectors and tanks were mounted on the campus of the UFU, evaluating the efficiency of systems with three measures of incident solar radiation and water temperature, working with systems naturally (thermosyphon) and pumped. The measures of temperature were acquired by a data acquisition system. Analyses of the heat losses from the reservoir of hot water were made and it was possible to estimate the thermal performance of solar heaters. The polypropylene collector showed a better thermal performance than PVC collector plates, it had transferred a greater quantity of useful heat to the water. For reservoirs of low cost analyzed, they had overall coefficients of heat exchange with the environment within the prescribed values of the literature and achieved values of thermal efficiency and temperature practically similar when operated in thermosyphon. When pumped, the solar heater of the polypropylene collector showed relatively results better than the solar heater of the PVC collector, and both systems have reached a greater thermal efficiency when pumped with flow rate of 40 L/h. Whereas the desired temperature to be reached by water is a little above the environment temperature, the results shows that although the low cost solar heaters have lower efficiencies achieved than conventional heater, they had a great thermal performance. Thus, the economic, social and environmental impacts generated with the use of this technology for residential water heating should be widely disseminated and popularized its use, especially among the poor.