THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

Fujun Ju

,

Wenbo Liu

,

Zhenzhen Mu

,

Xiaowei Fan

,

Huifan Zheng

,

Lihao Hou

,

Qinglei Liu

online first only

Experimental research on off-design characteristics of heat pump water heater using low GWP zeotropic blend

ABSTRACT
Based on the test setup of instant heat pump water heater (IHPWH), the performances of system operating with zeotropic natural mixture (ZNM) (R744/R290 (12/88)) and system operating with R22 refrigerant were compared under variable entry temperature of heat sink (ETHSK) and variable entry temperature of heat source (ETHSC) conditions, aiming to comprehensively evaluate the replacement potential of ZNM in the IHPWH. The results revealed that ZNM had an obvious alternative advantage, mainly attributed to that system operating with ZNM refrigerant achieved the comparable or markedly superior heating capacity and COP and markedly lower discharge temperature compared to those of system operating with R22 refrigerant under two conditions. The discharge temperature of system operating with ZNM refrigerant was reduced by 5.4~26.7℃ compared to that of system operating with R22 refrigerant, thus system operating with ZNM refrigerant can produce higher temperature domestic hot water. Compared with those of system operating with R22 refrigerant, both heating capacity and COP of system operating with ZNM refrigerant had markedly different trends with the change of ETHSK, while they had slightly different trends with the change of ETHSC. Compared to the ETHSK, the ETHSC has a more conspicuous impact on the heating capacity, COP and discharge temperature of system operating with ZNM refrigerant.
KEYWORDS
Off-design performances, Refrigerant substitution, Zeotropic natural mixture, R744/R290, heat pump water heater
PAPER SUBMITTED: 2024-01-25
PAPER REVISED: 2024-08-25
PAPER ACCEPTED: 2024-08-28
PUBLISHED ONLINE: 2024-10-12
DOI REFERENCE: https://doi.org/10.2298/TSCI240125210J
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Experimental research on off-design characteristics of heat pump water heater using low GWP zeotropic blend