Compression-assisted absorption refrigeration using ocean thermal energy

Abstract

Renewable ocean energy is regarded as an attractive candidate resource for the development of maritime cold chain systems. To meet the refrigeration requirement of seafood freezing and preservation storage, this study proposes two-type compression-assisted ammonia-water absorption refrigeration cycles using ocean thermal energy. The effects of intermediate pressure on the exergy efficiency and primary energy rate ratio are analyzed and discussed. Moreover, the role of the heat source and sink temperatures on the primary energy rate ratio was examined. The results indicated that the absorption refrigeration system with a compressor in the low-pressure stage has a higher exergy efficiency and a higher primary energy rate ratio than the corresponding compressor in the high-pressure stage. For a warm seawater temperature of 29 °C and cold seawater temperature of 8 °C, the low-pressure compression-assisted refrigeration cycle is the best solution with an exergy efficiency up to 0.284, and the optimal primary energy rate ratio equals 1.392. Furthermore, a higher primary energy rate ratio can be realized by increasing warm seawater temperature or reducing cold seawater temperature.