The purpose of this research is to reveal the exergy variation of each component in a direct-expansion solar-assisted heat pump(DX-SAHP)system.Exergy analysis of the DX-SAHP system with R134a is conducted,and the performance evaluation is done.The proposed system is mainly composed of a bare plate solar collec-tor/evaporator,a hermetic variable-frequency rotary-type compressor,a micro-channel condenser and an electronic expansion valve.The experimental data include the exergy loss rates,irreversibility rates and exergy loss ratios of all components and the influences of ambient temperature on these parameters.The analysis results show that the average irreversibility rate of the compressor is 204.8 W at an ambient temperature of 16℃,and 149.9 W at an ambient temperature of 27℃.The highest irreversibility rate occurs in the compression process,followed by the throttling process,the evaporation process and the condensation process.