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A study on the determination method of defrosting start time by calculation of frost volume.

Number: No 140

Author(s) : YOO J. W., CHUNG Y., KIM D. H., YOON S. H., SONG C. H., LEE K. H., KIM O. J., KIM M. S.

Summary

In cold winter season, most air heat pumps suffer from the frost formed on the surface of the outdoor heat exchanger. This frost must be removed, otherwise the heat pump performance will keep degrading and deviate from the design conditions, causing severe damage to the components. For this reason, it is necessary to determine the appropriate defrost start time. Several methods have been suggested, however, most of them are either based on empirical studies that require large number of experiments or less practical because they use expensive sensors. In this study, a new method is proposed to determine the defrost start time and verified with experiment. Three steps are required. First, calculate the frost mass that is generated per unit time using the heat and mass transfer analogy. Second, obtain the volume by dividing the frost mass with the density of frost.
Third, the frost volume generated per unit time is accumulated and compared with the heat exchanger volume to determine the defrost start timing. With this method, the defrosting operation can be appropriately initiated. 

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Pages: 7 p.

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Details

  • Original title: A study on the determination method of defrosting start time by calculation of frost volume.
  • Record ID : 30030007
  • Languages: English
  • Subject: Technology
  • Source: 13th IEA Heat Pump Conference 2021: Heat Pumps – Mission for the Green World. Conference proceedings [full papers]
  • Publication date: 2021/08/31

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