Journal of Shanghai Jiaotong University ›› 2013, Vol. 47 ›› Issue (03): 370-375.

• Energy and Power Engineering • Previous Articles     Next Articles

Effect of Refrigerant Charge on the Performance of a Direct Expansion Solar Assisted Heat Pump Water Heater Using R410A

 KONG  Xiang-Qiang-1, LIN  Lin-1, LI  Ying-1, ZHANG  Dong-2, YANG  Qian-Ming-1   

  1. (1.College of Mechanical and Electronic Engineering, Shandong University of Science and Technology,  Qingdao 266590, Shandong, China; 2.College of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, China)
  • Received:2012-04-09 Online:2013-03-28 Published:2013-03-28

Abstract: Based on the distributed parameter and homogeneous flow models of solar collector/evaporator and condenser, the lumped parameter models of compressor and electronic expansion valve and the refrigerant charge model, a simulation program of a direct expansion solar assisted heat pump water heater (DXSAHPWH) system using R410A was coded. For a fixed superheat degree at the collector outlet, the thermal performance parameters of the DX-SAHPWH system were obtained under different refrigerant charge conditions, and the effects of changing the refrigerant charge on the thermal performance of the system were analyzed. The results show that as the refrigerant charge increases, the evaporating pressure and heating time of the system decrease, but the instantaneous power of the compressor and the thermal efficiency of the collector increase. What’s more, the influences of the refrigerant charge on the condensing pressure and coefficient of performance (COP) of the system are very small.  

Key words: solar assisted heat pump, direct expansion, refrigerant charge, performance simulation

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