3785 -- Development of a Solar-Powered Freezer PDF

Describes a contribution to the development of a solar-powered freezer suitable for storing 9.1 kg (20 pounds) of medicine and vaccine at minus 10degC in remote tropical areas where electricity is not available. The system comprises a freezer unit and a solar-powered conversion/storage system that includes an array of photovoltaic cells and a battery. The freezer unit employs a conventional vapour-compression refrigeration cycle using R12 as a refrigerant and a capillary tube as an expansion device. The length of the capillary tube and the refrigerant charge were optimised at 3.41 m (11.18 ft) and 65.2 g (0.144 pounds) respectively, for the most efficient operation. Also investigates the effectiveness of photovoltaic cells in charging lead acid batteries to supply power to the freezer compressor. Describes performance tests carried out on the freezer.

KEYWORDS: Solar energy, photovoltaic cells, freezers, refrigeration, R12, tropics, medicine, performance, testing, capillary tubes, compression refrigeration