The Influence of Internal Heat Exchanger on the Performance of Transcritical CO 2 Water Source Heat Pump Water Heater

Fan Feng, Ze Zhang, Xiufang Liu, Changhai Liu and Yu Hou
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Fan Feng: State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Ze Zhang: State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Xiufang Liu: State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Changhai Liu: School of Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
Yu Hou: State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, China

Energies, 2020, vol. 13, issue 7, 1-14

Abstract: The characteristics of the transcritical CO 2 heat pump water heater (HPWH) system are; a lower inlet hot water temperature (T i-hw ) (sometimes this is lower than the water source temperature), and an outlet gas cooler temperature (T o-gc ) which is affected by the T i-hw and often lower than the critical temperature. In order to study the effects of the internal heat exchanger (IHX) on the operational performance of the transcritical CO 2 HPWH when T o-gc is low, a transcritical CO 2 water source HPWH experiment platform is established to conduct experimental research and comparative analysis on the operational performance of the transcritical CO 2 water source HPWH, with or without IHX. It is found that, if only the coefficient of performance (COP) and heating at the optimal exhaust pressure of the transcritical CO 2 water source HPWH were considered, COP and the heating of the non-IHX system would be slightly higher than those of the IHX system at the lower hot water flow and water source temperature, and this increase was not obvious. At the higher hot water flow rate and water source temperature, COP and the heating of the non-IHX system were also higher than those of the IHX system, and the increase was obvious. The experiment results showed that, near the optimal exhaust pressure, the variation range of COP and heating of the IHX system is relatively small, and the system has a relatively high stability.

Keywords: transcritical CO 2; heat pump water heater; internal heat exchanger (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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