A comparative performance study of concentrating PV/T and ETC for solar adsorption cooling system in Greece

This study explores the potential of combining concentrating photovoltaic thermal (CPV/T) solar collectors with a thermally driven adsorption chiller. The analysis is focused to the climate conditions of Athens, Greece, conducting on typical days in June, July, and August, when cooling demand is highest. Several configurations of the solar field are examined. The analysis begins with a solar field comprised entirely of evacuated tube collectors (ETC). CPV/T collectors are then incrementally added while proportionally reducing the ETC area, maintaining a consistent total solar field area of 50 m². The impact of positioning the CPV/T collectors either in series at the front of the ETC or in a parallel connection with them is assessed. Various performance metrics are used, including maximum and average COP, peak cooling capacity, cooling and electricity output, as well as energy and exergy efficiencies. The analysis reveals that the system performs best when using a solar field entirely composed of ETC, achieving an average COP of 0.40, a maximum cooling capacity of approximately 12 kW, and an energy efficiency of 21 %. In contrast, a setup with only CPV/T collectors yields the lowest performance. Mixed configurations, particularly those with 5 m² of CPV/T collectors added in parallel with ETCs, offer performance levels close to the full ETC setup, with an average COP of 0.39 and the added benefit of generating 3.25 kWh of electricity, based on the average from the three mean days across the three months examined.