空气源热泵相变蓄能除霜系统动态特性实验研究

Experimental study on the dynamic characteristics of novel phase change method-based defrosting for an air source heat pump

为研究空气源热泵相变蓄能除霜系统的除霜过程动态特性及性能,开展了空气源热泵相变蓄能除霜系统的实验研究,并与传统逆循环热气除霜进行了比较.实验结果表明,与传统空气源热泵逆循环除霜相比,相变蓄能除霜可使系统的除霜时间减少至少4 min,压缩机的排气压力、吸排气温度、功率及室外机平均壁温回升速度均明显加快;相变蓄能除霜可使除霜时压缩机吸气压力提高0.3 MPa,有效地避免了压缩机低压保护性停机;当系统由除霜转向恢复供热时,采用蓄能除霜,室内机出风温度比传统除霜高且升高速度较快,更有利于提高供热房间的舒适性.

Abstract：To study the defrosting performance and dynamic characteristics of novel phase change method-based defrosting for an air source heat pump （ASHP）, experiments were carried out and the results were compared with that of traditional reverse-cycle hot gas defrosting. Experiment results indicate that, compared with traditional reversecycle hot gas defrosting, PCM based defrosting decreases defrosting time by at least 4 minutes while the compressors discharge pressure, discharge and suction temperature, and power input increase faster, as well as the mean temperature of an outdoor coil. Furthermore, shutting down of an ASHP unit due to low suction pressure protection could be effectively avoided by increasing the compressor＇s suction pressure by about 0.3 MPa when the PCM based defrosting method is used. Additionally, when the system returns to the heating supply mode from the defrosting mode, with the PCM-based defrosting method, the air temperature out of the indoor coil increases faster and higher compared with traditional reverse-cycle hot gas defrosting, greatly enhancing the comfort of the heating space.