FOR RADIATIVE COOLING-

THE LOW-TEMPERATURE OF THE NIGHT SKY, TYPICALLY 8 DEGREES TO 20 DEGREES CELSIUS BELOW THAT OF THE AMBIENT AIR, POTENTIALLY CAN BE AN IMPORTANT RESOURCE FOR THE PASSIVE COOLING OF RESIDENTIAL AND COMMERCIAL BUILDINGS. UNTIL NOW THIS RESOURCE HAS NOT BEEN EFFECTIVELY EXPLOITED, LARGELY BECAUSE DURABLE, LOW-COST MATERIALS DO NOT CURRENTLY EXIST FOR MAKING INFRARED-TRANSPARENT GLAZINGS. WITHOUT SUCH A GLAZING, THE RADIATOR SURFACE COOLS WHEN EXPOSED TO THE SKY BUT REGAINS MUCH OF THE HEAT CONVECTIVELY BY COOLING THE OUTDOOR AIR. THIS REDUCES THE AMOUNT OF "COOLING POWER" AVAILABLE TO DISPLACE THE BUILDING'S THERMAL LOAD. THIS PROJECT IS TO DEVELOP A POLYMER FILM ABOUT 1 MM THICK WITH HIGH INFRARED TRANSPARENCY BETWEEN 8 AND 13 UM. HIGH- AND LOW-DENSITY POLYETHYLENE FILMS EXHIBIT THE HIGHEST INFRARED TRANSMITTANCE OF ALL POLYMERS WITHIN THIS REGION BUT FALL SHORT OF THE DESIRED GOAL BECAUSE OF THE PRESENCE OF ABSORBING NONETHYLENE GROUPS INCORPOR- ATED IN THE CHAIN. PURE POLYETHYLENE RESINS (WITHOUT ADDITIVES) WILL BE OBTAINED FROM MAJOR MANUFACTURERS AND SUBJECTED TO A VARIETY OF CHEMICAL AND PHYSICAL TREATMENTS TO REDUCE THE DETRIMENTAL INFRARED ABSORBANCE CAUSED BY SHORT-BRANCHING SIDE CHAINS AND THE PRESENCE OF UNSATURATED GROUPS IN THE POLYMER CHAIN. SAMPLES OF THE MOST TRANSPARENT FILMS AND THERMAL INSULATING FOAMS WILL BE MADE AND EVALUATED IN AN OUTDOOR RADI- ATIVE COOLING TEST ASSEMBLY.