Due to low thermal resistance, under strong sunlight, metal – sheet roofing may gain up to about 90 ~ 100PoPC and make a stiflingly hot air of more than 40PoPC inside the closed room it covers, which may affect badly to people's health and cause a large waste of energy, i.e. electricity, for running cooling systems. In order to improve thermal resistance of metal sheet roofing, several metal – sheet models containing a PCM layer together with several other insulation materials (i.e. EVA, PU…) have been experimentally investigated with a stable solar radiation modeling system which can offer a radiation density of around 1200W/mP2P. The models have been set to face that strong radiation within 4 hours (similar to or even more than the real period in the clearest sunny day at noon time) and then cool down naturally, all without any external wind on the outer surface. Results show that, while initial room temperature is 25PoPC, with the best model with PU+EVA+PCM, the inside air average temperature has been maintained at 27PoPC for up to 2 hours and has reached the maximum of only 32.7PoPC within 2 hours before dropping down again in the succeeding cooling period. This assures a much more convenient indoor air temperature condition and also good reduction of energy consumption for air conditioning purpose.
Clean Energy Technologies And Energy Efficiency For Sustainable Development 2010, 印度