Frost Formation and Defrosting of Tube-Array Evaporators in a Fluidized Bed and an Impinging Jet

Toshio Aihara, Hidetaka Gakumasawa, Shigenao Maruyama, Mitsuo Hongoh

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Frost formation on and choking of evaporators are perplexing problems in heat-pump systems using ambient air as the heat source. In the present study, heat-and mass-transfer, frost formation and defrosting of single row cooled-tubes were investigated experimentally in a uniform humid air flow, an impinging air jet, and a fluidized bed with a multi-slit distributor and a static-bed height of 10 mm, respectively. The heat transfer performance for an impinging jet decreased with time, because of the frost formation. As for teflon coated tubes in the present fluidized bed using glass beads of 0.92 mm in diam., it was found that non-frost operation is possible under comparatively wide conditions of heat flux and superficial velocity, and that the heat transfer performance is about five times that for the uniform air flow.

Original languageEnglish
Pages (from-to)1744-1748
Number of pages5
JournalTransactions of the Japan Society of Mechanical Engineers Series B
Volume54
Issue number503
DOIs
Publication statusPublished - 1988 Jan 1

Keywords

  • Convective Heat Transfer
  • Defrosting
  • Fluidized Bed
  • Frost Formation
  • Heat Pump
  • Impinging Jet
  • Mass Transfer

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering

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