Advanced Exergy Assessment of an Air Source Heat Pump Unit

Abstract

Energy conversation systems performance could be assessed by conventional exergy-based analysis methods. Along with the conventional exergy approach, the sources and amounts of the exergy destructions can be determined, and a possible direction for enhancement can be suggested. Nevertheless, interactions between system components (endogenous/exogenous) and technical constraints (avoidable/unavoidable) cannot be identified with any conventional analysis. Therefore, the real potential to improve and optimize can be misdirected. The advanced exergy-based analysis seeks to overcome this limitation. An air-source heat pump unit was assessed using conventional and advanced exergy analysis approaches, respectively. Avoidable/unavoidable and endogenous/exogenous exergy destructions, modified exergy efficiencies, and modified exergy loss ratios were calculated for every single component of the system. The results of the analysis showed that while the evaporator and condenser efficiencies could be improved through design improvements, the internal operating conditions were mainly responsible for the inefficiencies associated with the compressor. The analysis indicated that it was possible to improve evaporator and condenser efficiency by making design improvements. The efficiency of the compressor was mainly determined by the internal conditions in which the compressor operated.