Performance assessment of heat pump water heaters with R1233zd(E)/HCs binary mixtures

•R1233zd(E)/R1270 and R1233zd(E)/R290 are drop-in blends for heat pump water heaters.•Analysis with system COP and exergy efficiency obtains same optimal mass fraction.•Temperature glide of mixture impacts system COP in matching heat transfer curves.•Maximum COP of system is also corresponding to th...

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Bibliographic Details
Published in:Applied thermal engineering 2017-08, Vol.123, p.1345-1355
Main Authors: Ju, Fujun, Fan, Xiaowei, Chen, Yaping, Zhang, Honglin, Wang, Tuanjie, Tang, Xiangyang
Format: Article
Language:English
Subjects:
Binary mixtures
Evaporation
Exergy efficiency
HCs
Heat exchangers
Heat pump water heaters
Heat transfer
Hydrocarbons
Performance assessment
Pumps
R1233zd(E)
Refrigerants
Water heaters
Zeotropic mixtures
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Summary:•R1233zd(E)/R1270 and R1233zd(E)/R290 are drop-in blends for heat pump water heaters.•Analysis with system COP and exergy efficiency obtains same optimal mass fraction.•Temperature glide of mixture impacts system COP in matching heat transfer curves.•Maximum COP of system is also corresponding to the lowest compressor pressure ratio.•Maximum COP with R1233zd(E)(16%)/R1270 is 4.646 which is 2.18% higher that with R22. The eco-friendly zeotropic mixtures of R1233zd(E) with four hydrocarbons were investigated to replace the traditional refrigerants (R22 and R134a) in heat pump water heaters. Under the nominal working condition, the performances of heat pump were analyzed by establishing the mathematical model based on the fixed pinch point temperature difference in the heat exchangers. The results show that both blends R1233zd(E)/R1270 and R1233zd(E)/R290 are suitable drop-in candidates of R22 or R134a for heat pump water heaters. The R1233zd(E)/R1270 with optimal mass fraction 16%/84% demonstrates the best system COP which is respectively 2.13% and 10.14% higher than those of R22 and R134a. The temperature glide feature of zeotropic mixture influences on the system COP greatly in matching both heat transfer processes in condenser and evaporator. The heat sink outlet temperature influences the system COP greatly that when it is 45, 55 or 65°C, the corresponding maximum system COP is 5.803, 4.646 or 3.888 with R1233zd(E)/R1270 and 5.724, 4.535 or 3.757 with R1233zd(E)/R290 respectively. Also, the optimal fraction of R1233zd(E) shifts to a slightly higher value with the rise of heat sink outlet temperature.
ISSN:1359-4311
1873-5606
DOI:10.1016/j.applthermaleng.2017.05.137