Heat transfer issues in laminar flow of single-phase secondary refrigerants through the pipes.

Author(s) : HRNJAK P. S.

Summary

Three experimental programmes are described (in a display case, local heat transfer measurements, and an air cooler) and major findings are presented. The reason for good heat transfer on the refrigerant side is due to long and most importantly technically significant thermally developing region in laminar flow of secondary refrigerants at very high Prandtl number and positive effect of return (U bends). It was shown that the secondary flows in U bends recover heat transfer coefficients in the same way and to even slightly higher value than in thermally developing region. Result is effectively very high refrigerant side heat transfer coefficient, higher in average than evaporating two-phase refrigerants with a common superheat. This is particularly true for potassium formate that exhibited slightly higher heat transfer coefficients at lower pressure drops.

Details

  • Original title: Heat transfer issues in laminar flow of single-phase secondary refrigerants through the pipes.
  • Record ID : 2005-0886
  • Languages: English
  • Source: Advanced supermarket refrigeration/heat recovery systems. Workshop proceedings [CD-ROM].
  • Publication date: 2000/10/02

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