TY - JOUR
T1 - Improving the frosting and defrosting performance of air source heat pump units
T2 - review and outlook
AU - Song, Mengjie
AU - Dong, Jiankai
AU - Wu, Chili
AU - Jiang, Yiqiang
AU - Qu, Minglu
N1 - Publisher Copyright:
© 2017 The Hong Kong Institution of Engineers.
PY - 2017/4/3
Y1 - 2017/4/3
N2 - When air source heat pump (ASHP) units operate in heating mode at low temperatures in high humidity environments, frost forms and accumulates on the surface of its outdoor coils. This frost layer adversely degrades the operating efficiency of ASHP units rapidly, and can even result in sudden shutdown. Due to this operational problem, many researchers have conducted studies on frost-retardation measures. Since the frost that is present on the ASHP unit after shutdown has to be removed, defrosting becomes necessary. Among several reported defrosting methods, such as compressor shutdown defrosting, electric heating defrosting, hot water spray defrosting and hot gas bypass defrosting, the most popular method is reverse cycle defrosting. In addition, defrosting initiation and termination control play an important role in the frosting and defrosting cycle. Due to a scarcity of reviews of the literature on improving the frosting and defrosting performance of ASHP units, this paper provides a comprehensive review of experimental and modelling studies which explore this topic. This review can be used for guiding the future design and control strategy optimisation for ASHP units.
AB - When air source heat pump (ASHP) units operate in heating mode at low temperatures in high humidity environments, frost forms and accumulates on the surface of its outdoor coils. This frost layer adversely degrades the operating efficiency of ASHP units rapidly, and can even result in sudden shutdown. Due to this operational problem, many researchers have conducted studies on frost-retardation measures. Since the frost that is present on the ASHP unit after shutdown has to be removed, defrosting becomes necessary. Among several reported defrosting methods, such as compressor shutdown defrosting, electric heating defrosting, hot water spray defrosting and hot gas bypass defrosting, the most popular method is reverse cycle defrosting. In addition, defrosting initiation and termination control play an important role in the frosting and defrosting cycle. Due to a scarcity of reviews of the literature on improving the frosting and defrosting performance of ASHP units, this paper provides a comprehensive review of experimental and modelling studies which explore this topic. This review can be used for guiding the future design and control strategy optimisation for ASHP units.
KW - Air source heat pump (ASHP)
KW - control strategy
KW - defrosting
KW - frost retardation
KW - multi-circuit outdoor coil
UR - http://www.scopus.com/inward/record.url?scp=85024401715&partnerID=8YFLogxK
U2 - 10.1080/1023697X.2017.1313134
DO - 10.1080/1023697X.2017.1313134
M3 - Article
AN - SCOPUS:85024401715
SN - 1023-697X
VL - 24
SP - 88
EP - 98
JO - Transactions Hong Kong Institution of Engineers
JF - Transactions Hong Kong Institution of Engineers
IS - 2
ER -