Seasonal coolth storage system for residential buildings in Australia

Abstract

Night sky cooling is explored as an alternative to the conventional cooling technologies using fossil fuels. The night sky cooling method is based on the long wave radiation of unglazed collectors to the sky at night. An evaluation of the night sky cooling system is present for a residential building in three cities of Australia, namely Alice Springs, Darwin and Melbourne. The system comprises an unglazed flat plate solar collector integrated with borehole storage. It uses night sky radiation to reduce the temperature of the ground near to the boreholes. The system was simulated with TRNSYS, a transient simulation program. The simulation results for adequately sized systems show that night sky radiation is able to reduce the coolth storage borehole temperature and the proposed system is able to meet the cooling load of the residential building simulated in three locations. Borehole lengths of 270, 318 and 106 m are required for coolth storage with 90, 260 and 14 m² collector area for heat rejection in Alice Springs, Darwin and Melbourne, respectively. At the 20th simulation year, the proposed system is able to achieve a system cooling coefficient of performance of 2.2 in Alice Springs, and 2.8 in Darwin and Melbourne.

Keywords

night sky cooling / borehole / coolth storage / unglazed solar collectors

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