并联毛细管小型二氧化碳热泵系统的除霜性能
Defrosting performance of small parallel capillary carbon dioxide heat pump systems
摘要：
空气源跨临界二氧化碳热泵系统具有较高的制热性能系数，但在蒸发器结霜工况下运行时，会出现供热量和性能系数下降的现象。介绍了一种以并联毛细管代替电子膨胀阀作为节流部件的热泵系统,并进行了除霜性能实验。实验结果表明：并联毛细管热泵系统的除霜效率略小于常规热泵系统，但是除霜过程较平稳，可实现连续制热，也无需对压缩机运行进行特别保护。不仅简化了除霜系统，也避免了机组除霜结束恢复制热时重启压缩机的困难。
Abstract：
A transcritical carbon dioxide air-source heat pump system has attracted the attention of researchers due to its high heating coefficient of performance. However, when operating under the frosting conditions of the evaporator, the heat supply and the coefficient of performance decrease. Presents a heat pump system using parallel capillary instead of an electronic expansion valve as a throttling component, and tests the defrosting performance. The experimental results show that the defrost efficiency of the parallel capillary heat pump system is slightly lower than that of the conventional heat pump system, but the defrosting process is relatively stable to realize the continuous heating, and the compressor is not required to be specially protected, which not only simplifies the defrosting system, but also avoids the difficulty of restarting the compressor when the heating is restored after defrosting.
Keywords:parallel capillary, carbon dioxide, heat pump system, defrosting, coefficient of performance