Compressors for ammonia-water hybrid absorption-compression heat pumps

Abstract

In this paper, investigations on the development of industrial high temperature heat pumps are carried out based on the analysis of the current available compressors. The compressor used for the ammonia compression is a major component of ammonia-water hybrid absorption-compression heat pump. Furthermore, the compressor is the dominant constraint on achievable process conditions due to the limitation of high pressure and discharge temperature. Ammonia-water hybrid heat pumps combine technologies of an absorption and compression heat pump with a mixture of ammonia and water as working fluid. The heat is extracted and emitted at non-constant temperature glides and the necessary ratio of compression is lower compared to conventional compression heat pumps. These properties make the hybrid heat pump interesting for use in industrial high temperature applications. In this study, currently available compressors are being investigate for a utilization of them in a hybrid heat pump test facility able to operate at high side pressures to achieve exit temperatures on the secondary side of 140 °C to 180 °C. For this purpose, available compressors are identified and evaluated based on performance indicators such as the maximum pressure and discharge temperature.