Improving the frosting and defrosting performance of air source heat pump units: review and outlook
Abstract
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.
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In open literature, most scholars regarded the total mass of melted frost as frost accumulation for further calculations.
“Therefore, in open literature, most scholars regarded the total mass of the melted frost as frost accumulation, to conduct further calculations [2,101,103,115,120,124,125].”
From Review on the measurement and calculation of frost characteristics (2018) · cites this paper as [2]
Later, the effects of melted frost on defrosting performance were demonstrated and investigated.
“Later, the effects of melted frost on the defrosting performance were demonstrated and investigated [2,101,123].”
From Review on the measurement and calculation of frost characteristics (2018) · cites this paper as [2]
Cites
An experimental study of frost formation on a horizontal cylinder under cross flow
Lee, Y. B., & Ro, S. T. (2001) · International Journal of Refrigeration · doi:10.1016/s0140-7007(00)00073-6 · Cited by 95 · cited 1× · see citing works
“When this happens, it may change the structure of the frost layer, increase its density and enhance its thermal conductivity [75].”
BackgroundZhang, P., & Hrnjak, P. S. (2009) · International Journal of Refrigeration · doi:10.1016/j.ijrefrig.2008.11.006 · Cited by 75 · see citing works
Frosting performance of tube fin heat exchangers with wavy and corrugated fins
Kondepudi, S. N., & O'Neal, D. L. (1991) · Experimental Thermal and Fluid Science · doi:10.1016/0894-1777(91)90040-x · Cited by 71 · cited 1× · see citing works
“component optimisation due to its characteristic of system operation [32].”
BackgroundYe, H.-Y., & Lee, K.-S. (2013) · International Journal of Heat and Mass Transfer · doi:10.1016/j.ijheatmasstransfer.2013.08.026 · Cited by 70 · cited 1× · see citing works
“In another study, a numerical model was developed and experimentally validated, showing that changes in different ambient air parameters have different effects on the rate of frost retardation [9].”
MethodSong, M., Deng, S., Pan, D., & Mao, N. (2014) · Applied Thermal Engineering · doi:10.1016/j.applthermaleng.2014.03.020 · Cited by 66 · cited 3× · see citing works
“The negative effects of melted frost flowing down the surface of the outdoor coil have been demonstrated as the major reason for the phenomenon of uneven defrosting [39,40].”
BackgroundResultSelf-citationElectric defrosting analysis of a finned-tube evaporator coil using the enthalpy method
Alebrahim, A. M., & Sherif, S. A. (2002) · Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science · doi:10.1243/095440602320192300 · Cited by 26 · see citing works
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Review on improvement for air source heat pump units during frosting and defrosting
Song, M., Deng, S., Dang, C., Mao, N., & Wang, Z. (2018) · Applied Energy · doi:10.1016/j.apenergy.2017.12.022 · Cited by 384 · see citing works
Self-citationReview on the measurement and calculation of frost characteristics
Song, M., & Dang, C. (2018) · International Journal of Heat and Mass Transfer · doi:10.1016/j.ijheatmasstransfer.2018.03.094 · Cited by 212 · see citing works
Self-citationEnhancing heat-exchanger performance in frost conditions via superhydrophobic surface modification
He, H., Zhou, X., Lyu, N., Wang, F., Liang, C., & Zhang, X. (2024) · Applied Thermal Engineering · doi:10.1016/j.applthermaleng.2024.122914 · Cited by 19 · see citing works
Tang, L., Liu, X., He, S., & Li, Q. (2024) · Journal of Building Engineering · doi:10.1016/j.jobe.2024.108739 · Cited by 6 · see citing works
- Authors
- Song, M., Dong, J., Wu, C., Jiang, Y., & Qu, M.
- Affiliations
- Guangdong University of Technology (CN)
- Harbin Institute of Technology (CN)
- Hong Kong University of Science and Technology (HK)
- University of Shanghai for Science and Technology (CN)
- Corresponding author
- Wu, Chili
- Venue
- HKIE Transactions
- Published
- 2017-04-03
- Volume
- 24
- Issue
- 2
- Pages
- 88-98
- ISSN
- 1023-697X (ISSN-L)
- 2326-3733
- OpenAlex
- W2736142614
- Cited by
- 53
- References
- 6
- Citations by year
- 2026: 5 · 2025: 6 · 2024: 9 · 2023: 5 · 2022: 6 · 2021: 2 · 2020: 5 · 2019: 5 · 2018: 4 · 2017: 6
- FWCI
- 4.25
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- HKIE Transactions (publishedVersion)
- Funders
- National Natural Science Foundation of China (no. 51606044)
- Science and Technology Planning Project of Guangdong Province, People’s Republic of China (no. 2014B090903007)
- One-Hundred Young Talents Project of the Guangdong University of Technology (o. 220413529)
- Topics
- Physical Sciences › Engineering › Mechanical Engineering › Refrigeration and Air Conditioning Technologies
- Physical Sciences › Engineering › Mechanical Engineering › Adsorption and Cooling Systems
- Physical Sciences › Engineering › Building and Construction › Building Energy and Comfort Optimization
- Keywords
- air-source heat pump, frost formation, thawing, low-temperature heating, high humidity, reverse cycle defrosting
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