由于传统的人工合成制冷剂对环境的不良影响,环保的自然工质CO2重新兴起。提高CO2跨临界循环系统的效率成为CO2制冷技术发展的一个研究重点。采用膨胀机可以提高CO2跨临界循环系统的效率,使其接近普通制冷系统的效率。在原有单缸滚动活塞膨胀机的基础上,设计并加工了新型双缸膨胀机样机,对其设计过程、运动原理等进行了介绍,并利用CO2跨临界水-水热泵系统对样机进行了性能测试,测试结果显示,在试验工况下,膨胀机的转速为780~1100r/min,其等熵效率的为28%~33%。
Improving the efficiency of CO2 trans-critical systems has been the subject of much research in the refrigeration technologies development.In our study, a new two-cylinder expander was designed and fabricated on the basis of our previous single-cylinder rolling-piston expander.A CO2 trans-critical water-water heat pump system was applied to test the efficiency of the expander presented.The test results show that the efficiency was 28%-33% when the rotating speed of the expander ranged from 780 to 1100 r/min under the testing conditions.