带膨胀机的二氧化碳跨临界循环水源热泵系统运行特性实验研究

虽然二氧化碳跨临界循环成为最具潜力的工质替代技术，但其循环的效率还是比常规工质循环低，因此开发膨胀机提高二氧化碳跨临界循环系统运行效率是推动实际应用的关键问题。本文给出了二氧化碳膨胀机的设计特点，同时利用实验手段对带膨胀机的二氧化碳跨临界循环水源热泵系统进行测试，了解膨胀机的运行特性以及对系统的影响，同时改变外部参数条件，了解系统运行规律。通过实验表明，膨胀机的运行效率与膨胀机的转速有关，而且存在极值。系统的运行也受其影响，但系统性能系数是一个综合作用的结果，应对系统运行参数进行优化。

EXPERIMENTAL STUDY OF PERFORMANCE CHARACTERISTICS ON CARBON DIOXIDE TRANSCRITICAL CYCLE WITH AN EXPANDER WATER SOURCE HEAT PUMP

Although CO2 transcritical cycle has been a most potental alternitive technology, which has a low coefficient of performance compared with present conventional high performance refrigerant system. So success development of CO2 expander to improve coefficient of performance still is critical to the success of CO2 system on the application. The features of the CO2 expander were presented. Experiments were conducted on the CO2 transcritical cycle with an expander water source heat pump in order to understand the performance properties of CO2 expander and its influence on the whole system. The performance characteristics of the system were mastered by test with various outside conditions. The experimental results show that the efficiency of expander is relational to its revolution speed and there exists an optimum value to make the efficiency maximum. The expander also has an impact on the implementation of the whole system, but the coefficient of performance of the system is the final integrated effect by all factors. Optimization of operating parameters is needed therefore.