Annual report covering period 26 Jan 1995-31 Jan 1996 : materials for passive radiative cooling

Thus cooling can be obtained without needing any external energy source. This project aims to develop both the emitter (in Peru) and shield (in Israel) to the point where a commercial passive cooler can be produced, with emphasis on simple and cheap technologies. Selective emitters have been made using a simple spray method from silicon oxynitride, using silica and ammonia. Shields have been investigated based on polyethylene sheet as substrate (one of the few practical materials for this purpose) coated with tellurium by an indirect electrotechnical method. More recently, lead selenide, deposited directly on the polyethylene by a simple chemical solution method, has shown promise for the shield. This latter material is a novel one for this purpose and if as good (if not better) than Te, would be preferable due to the great simplicity of the deposition method. Since the first year has been largely exploratory, with much time invested in techniques and equipment, each team has worked independently. During the second year, the output of both teams will start to be combined and actual devices will be measured. (Author abstract)