Numerical simulation and parametric study of different types of solar cooling systems under Mediterranean climatic conditions

Solar driven cooling systems can be a promising alternative to traditional electrical grid powered air conditioning plants. These systems use either thermal or electrical processes to convert solar radiation into cooling. Despite the numerous theoretical and experimental researches that have been carried out in recent years on solar cooling it is still not clear which system presents the best performance. In this study the performance of three different solar cooling systems is examined, namely: 1) a solar electrical, 2) a solar thermal and 3) a hybrid solar electrical-thermal cooling system. The first one system uses PV collectors in order to supply a conventional electrical vapor compression chiller. The second one utilizes thermal collectors in order to power a heat driven adsorption chiller and the third one utilizes PV/T collectors to feed both an electrical and an adsorption chiller. The study is performed for Athens, Greece climatic conditions during an assumed summer period from May to September. The optimum tilt angle of the solar collectors is calculated for maximization of the solar radiation during summer period. It is found to be 14°. The best performance is observed for the solar electrical cooling system utilizing the mono-Si PV modules with a maximum Solar COP of around 0.47 while the lowest is presented by the a-Si PV modules powered cooling system with a minimum Solar COP of about 0.13.