Modelling Approach for a Liquid-Injected Ammonia-Water Screw Compressor

Abstract

The present work focuses on a modelling approach for a liquid-injected ammonia-water screw compressor for combined absorption-compression heat pumps (CACHP) at high-temperature operation. The CACHP system combines the technologies of an absorption and vapor compression heat pump with a mixture of ammonia and water as working fluid. The functionality of this process has already been proven in the industrial sector using standard refrigeration components. In recent years, several studies have investigated the CACHP system to identify challenges and opportunities to increase the achievable temperature range and optimize process performance. The compressor was identified as a main critical component for increasing the achievable sink outlet temperature level. For this purpose, this study identifies currently available modelling approaches of liquid-injected screw compressors and investigates their usability in a CACHP system. Based on this, an approach for the modelling of liquid-injected ammonia-water screw compressors is developed.