Part-load based optimization of solar ejector cooling cycle

Abstract

The thermodynamic and economic performance of a solar ejector cooling cycle (SECC) driven by flat plate collectors is investigated considering its part-load behavior. An SECC operating with R1234ze(E) is optimized for different collector areas from 50 to 150 m² and specific storage tank volumes from 50 lt/m² to 150 lt/m² per collector area, considering climate data of four cities (Athens, Madrid, Nicosia and Rome) to maximize seasonal cooling according to partial and full day cooling schedules. The ECC optimization variables are the nominal heat transfer fluid (HTF) temperature at the generator inlet and cooling fluid temperature at the condenser/subcooler inlet. Optimal HTF and cooling fluid temperatures are 86–87 °C and 30–33 °C, respectively, showing minor variation for different conditions. The produced cooling is lowest in Nicosia (4–24 kWh_c/m²) and highest in Madrid and Athens (17–45 kWh_c and 12–38 kWh_c/m²), with significantly improved performance under full day cooling schedule. Higher specific tank volumes result in slight and significant increase in cooling production under the partial and full day cooling schedules, respectively. According to techno-economic results, the investigated SECC is a non-viable solar thermal cooling option because of its poor solar cooling conversion efficiency.