PERFORMANCE CHARACTERISTICS OF SCROLL EXPANDER FOR CO_2 REFRIGERATION CYCLES

摘要

To help lesser the effects of global wanning, CO_2 refrigeration cycles are required in refrigeration and air-conditioning applications. Work-output expansion devices (expanders) are needed to improve the system performances, but their efficiencies are still too low to make the systems practical. The improvement in the COP of a CO_2 refrigeration cycle is highly dependent on expander efficiency.To solve this problem, we developed a prototype of a scroll expander for CO_2 refrigeration cycles and studied its performance characteristics. The experimental parameters are rotational speed, inlet pressure and temperature, exit pressure, and CO_2 mass flow rate of the scroll expander. The test results show that our scroll expander had maximum measured isentropic efficiencies greater than 70%. We confirmed that our scroll expander has a high potential for making CO_2 refrigeration systems practical.