ANALYSIS AND PERFORMANCE EVALUATION OF AN UNDERGROUND SOLAR AIRHEATERCOUPLED NON-AIRCONDITIONED BUILDING FOR HYBRID SPACE CONDITIONING

This communication presents a theoretical model of a hybrid active/pas sive system for space heating of a non-airconditioned building. The sy stem consists of an underground air heater as solar collection cum sto rage system coupled with a non-airconditioned building to be heated. T he model takes into account the periodicity of the solar intensity and ambient air temperature, recirculation of room air through an undergr ound air heater, as well as periodic heat transfer to the ground, wall s/roof and furnishings as a function of time. The effects of air heate r design and other budding parameters on the indoor room air temperatu re have been studied. It is found that room air temperature decreases with increasing depth of the heat retrieval plane and increases with i ncreasing air mass recirculation rate. The thermo-physical properties and the surface conditioning of the soil above the plane of heat retri eval significantly improve the air heating efficiency of the proposed hybrid system.