24 June 2014

Theoretical Evaluation of Ejector- Based Heat Pump Cycles for cold climates


In this study, different configurations of an ejector system assisted by solar energy or waste heat are proposed and investigated in order to increase the performance of residential air
source heat pumps in cold climates. Besides the conventional heat pump which is used as a reference, three more configurations of compressor-ejector cycles were selected for this study: a hybrid ejector-compressor booster and two cascade compressor-ejector cycles. The modeling
methodology developed to handle such systems is based on the principles of thermodynamics and fluid dynamics. This cycle model is used in combination with a validated ejector model and manufacturer’s compressor performance maps. Conjugate effects of the thermal and mechanical
compression components and sub-cycles interactions on the system performance are investigated.
Performance analysis is assessed to compare these cycles. For fixed working conditions, substantial
improvement in COP of the selected cycles over the conventional heat pump cycle is found.