Variations of Vapour Compression Refrigeration Systems Cooling Loads with Varying Solar Insolation

Abstract

Solar energy is readily available but intensity fluctuates with the seasons of the year in many. Due to this fluctuation, there exists a mismatch between solar energy availability and cooling load energy demands in solar technology, which make them inefficient and unreliable at certain times depending on weather and season. Sufficient harnessing and storage of solar energy for use in solar energy applications, is critical for improvement of efficiency and reliability of solar technologies. This is only possible if the solar driven refrigeration system utilizes the maximum solar energy available at a specific site, and stores some of the energy in form of ice thermal load systems. This study has analyzed three different sizes of solar vapour compression refrigeration systems, each fitted with an AC compressor. Four PV panels each of 200Wp were connected to the systems and exposed to different levels of solar insolations for the same period of time. The maximum cooling loads from each system, was established by temperature drop of the water in the cooling can and the mass of ice formed in a jacket of cooling water for each of the systems. An innovative control unit controlled the running of the compressors, depending on the solar insolation required by each compressor. The number of hours each compressor ran per day was recorded by a datalogger. Results showed that solar refrigeration systems with AC compressors exhibited a maximum cooling load for different refrigeration system AC compressors, which is dependent on the solar insolation of a specific location.