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Experimental study on frost growth and dynamic performance of an air source heat pump (ASHP) system.

Author(s) : GUO X. M., CHEN Y. G., WANG W. H., et al.

Summary

The frost thickness has been measured by using micro-photograph, and the frost accumulation mass was estimated in terms of the difference in measured humidity before and after the test evaporator. The experimental results indicate that the frost layer grows in a manner of three stages. In the initial frosting stage, the frost grows quickly and the performance of the ASHP unit is slightly improved. After the initial stage, the frost thickness growth rate decreases with the frosting time, the performance and the refrigerant-side parameters of the ASHP system are only slightly affected by frosting on the outdoor coils. In the third frosting stage, the frost thickness growth rate increases sharply to about 3-5 times that in the second stage, and the performance of the ASHP unit decays rapidly. The observation on the frost layer suggested that the rapid decrease in the performance of the ASHP unit is caused by the morphological variation of the frost crystals. It was found in the experiments that the duration of the second frosting stage is significantly affected by the outdoor air relative humidity, but these of the initial and the third frosting stages are nearly invariable for the outdoor air relative humidity ranging from 65 to 85% with a constant outdoor air temperature.

Details

  • Original title: Experimental study on frost growth and dynamic performance of an air source heat pump (ASHP) system.
  • Record ID : 2008-2534
  • Languages: English
  • Source: Cryogenics and refrigeration. Proceedings of ICCR'2008.
  • Publication date: 2008/04/05

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