CO2充注量对跨临界轿车空调系统性能的影响

试验研究了CO₂充注量对跨临界轿车空调系统性能的影响.研究表明：CO₂充注量对跨临界制冷系统的性能影响很大，存在一个最佳的CO₂充注量，此时COP最大;CO₂充注量不足，会导致制冷量和COP降低，CO₂充注量过多，会导致压缩机耗功大幅度上升;制冷循环随CO₂充注量的不同，具有6个特征明显的工作循环.根据这些表现特征，提出了用4个参数作为判断CO₂充注量是否合适的特征参数.为确定跨临界制冷系统的最佳充注量、对系统进行优化设计和高效运行控制提供了参考.

Impact of CO2 mass charge on trans-critical automotive air conditioning system

In this paper, an experiment was carried out to evalua te the impact of CO_2 mass charge on a CO_2 automotive air conditioner.The CO_2 air conditioner was designed to have heat exchanger dimensions nearly identical to conventional R134a systems.The heat exchanger was made of fin-tubes,the com pressor was of swash plate design, and a manual expansion valve and an internal heat exchanger accumulator were used. The experimental results show that the coe fficent of performance (COP)was strongly related to CO_2 mass charge and the fo rmation of the trans-critical cycle depended on CO_2 mass charge greatly.The C OP has a maximum value at a specific CO_2 mass charge. Undercharged CO_2 syste ms could result in a fast decrease of the cooling capacity and COP;however, over charged CO_2 systems could cause an abrupt increase of compressor power consump tion.The refrigerating cycle displayed different characteristics with different CO_2 mass charges.The optimum CO_2 mass charge could be determined according t o four state parameters.