Performance of air source heat pump units with different wettability evaporators

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Zhaolin Gu
  • Yang Zhang
  • Zhang Li
  • Zanshe Wang

Detail(s)

Original languageEnglish
Article number124458
Journal / PublicationApplied Thermal Engineering
Volume257
Issue numberPart C
Online published21 Sept 2024
Publication statusPublished - 15 Dec 2024

Abstract

The air source heat pumps (ASHPs) for winter heating have the advantages of high efficiency and environmental protection. However, the outside evaporator's frosting negatively impacts the performance of heat pump systems in low-temperature and high-humidity environments. In this paper, we fabricated the superhydrophobic evaporator and mounted it on a commercial ASHP unit, expanding the use of superhydrophobic surface modification technology from heat exchangers in the laboratory to the ASHP units. Then we investigated the operating characteristics of two ASHP units equipped with hydrophilic and superhydrophobic evaporators respectively under six distinct outdoor and indoor environmental conditions experimentally. In the non-frosting conditions, film condensation formed on the surface of the hydrophilic evaporator and the evaporation temperature decreased with the formation of water film, resulting in a decrease in heat production and COP. In the frosting conditions, the time of forming the frost layers with the same thickness on the superhydrophobic surface was more than 4 times longer than that on the hydrophilic surface. The COP of the superhydrophobic evaporator unit was improved by 2.9% to 8.2% under the non-frosting conditions, by 11.5% under the continuous heating conditions and by 14.28% when the hydrophilic unit performed two defrosting cycles, respectively. During the period in which the hydrophilic evaporator unit completed two frosting/defrosting cycles, the energy loss coefficient caused by the defrosting process was 31.65% compared to the superhydrophobic evaporator unit. This work extended the experimental method of superhydrophobic heat exchanger, contributing to the application of superhydrophobic finned-tube evaporators in ASHP units. © 2024 Elsevier Ltd

Research Area(s)

  • Frosting, Heat pump, Heating capacity, Superhydrophobic finned-tube evaporator

Citation Format(s)

Performance of air source heat pump units with different wettability evaporators. / Li, Ran; Gu, Zhaolin; Zhang, Yang et al.
In: Applied Thermal Engineering, Vol. 257, No. Part C, 124458, 15.12.2024.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review