As a novel generation of rotary thermal separators, a wave rotor refrigerator (WRR) is an unsteady flow device used for refrigeration in whose passages pressured streams directly contact and exchange the energy due to the movement of pressure waves. In this work, the working procedure and wave diagram of WRR are investigated thoroughly. Based on this, a novel WRR thermodynamic analysis model has been established and validated by experiments. This performance assessment model shows the main contributing factors of expansion and compression processes. A particular analysis of WRR refrigeration system has revealed that expansion efficiency can be adversely affected by excessive high compression efficiency, which means that particular emphasis should be laid on wave rotors for supercharging or refrigeration.