This paper provides a performance comparison of solar cooling systems. Twenty solar-thermal cooling system combinations based on five thermal/ PV cooling cycle technologies and three collector types have been identified with respect to four operating temperature ranges. These are liquid- and solid-based systems in open- or closed-cycle configurations, from absorption to Rankine heat engine technologies, powered by heat derived from flat-plate to concentrating collectors. The four operating temperature ranges used are 12ºC to 20 °C, 4ºC to 12 °C, -17ºC to 0 °C, and -40ºC to -20 °C for high- to low-temperature air-conditioning and high- to medium- and medium- to low-temperature refrigeration applications. The systems have been compared using the solar coefficient of performance (SCOP); this combines the solar collector aperture area efficiency with the efficiency of the cooling cycle. It has been shown that across 7ºC to 13.5 °C (within 12ºC to 20 °C) application temperature range for double-effect absorption (LiBr-H₂O), the highest SCOP efficiency of 0.933 was achieved. In this range, the PV-compression system achieves the highest SCOP of approximately 1.1 at 20 °C. With the exception of the one-stage (NH₃/H₂O) unit, the PV-compression system is shown to be the most efficient for cold storage and ice-making applications at -17ºC to 0 °C, 0.375- 0.525. Moreover, for deep-freezing at -40ºC to -20 ° C, the suitability of PV-compression and single-effect (NH₃/H₂O), respectively, are: 0.226 (-30 °C) to 0.314 (-20 °C) and 0.220 (-40 °C) to 0.295 (-20 °C). These results can be used to assess the relative performance of sorption systems as compared to vapor compression system.

Units: SI