PERFORMANCE OF AN UNGLAZED TEXTILE-PLASTIC SOLAR-ABSORBER

A simple solar water heating system comprising an unglazed textile-pla stic absorber and an uninsulated plastic accumulator tank with thermos iphon flow of heat transporting fluid has been tested under outdoor co nditions. The unglazed textile-plastic absorber is very sensitive to c hanges in climatic conditions. The overall efficiency and the response time to changes in irradiation depend also from ambient air temperatu re, absorber temperature and intensity of solar radiation. Under good conditions its efficiency is comparable with that of sophisticated met allic collectors (e.g. with selective absorbing layers), but on cold d ays when the intensity of solar radiation is low it is considerably lo wer. For some applications, where only a small rise in water temperatu re is needed, such as swimming pool water heating or water preheating for irrigation in greenhouses, they may be more cost effective than me tallic solar collectors, when their low price is taken into account. ( C) 1998 Elsevier Science Ltd. All rights reserved.