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AIR-TO-AIR HEAT PUMPS OPERATING UNDER FROSTING CONDITIONS ON THE OUTDOOR COIL.

Author(s) : TANTAKITTI C., HOWELL R. H.

Summary

A PROGRAM WAS DEVELOPED TO INVESTIGATE THE EFFECTS OF FROST DEPOSITED ON THE OUTDOOR COIL OF AIR-TO-AIR HEAT PUMPS. 3 METHODS OF DEFROST INITIATION WERE INVESTIGATED: (1) AIR PRESSURE DROP ACCROSS THE COIL ; (2) COMBINATION AIR TEMPERATURE AND COMPRESSOR RUN TIME ; (3) COMBINATION OF EVAPORATOR TEMPERATURE AND COMPRESSOR RUN TIME. THE SETPOINTS WERE VARIED TO DETERMINE THEIR EFFECT ON THE AMOUNT OF FROST AND THE NUMBER OF DAILY DEFROSTS AT DIFFERENT AMBIENT TEMPERATURES AND RELATIVE HUMIDITIES. A RESIDENCE WAS USED TO GENERATE HEATING AND COOLING LOADS. THE SIMULATION SHOWED THAT THE AMOUNT OF FROST WAS INDEPENDENT OF THE METHOD OR THE SETPOINT OF DEFROST INITIATION. FROM AN ENERGY POINT OF VIEW, THE DEMAND DEFROST TECHNIQUE APPEARS TO BE THE BEST CRITERIA FOR DEFROST INITIATION.

Details

  • Original title: AIR-TO-AIR HEAT PUMPS OPERATING UNDER FROSTING CONDITIONS ON THE OUTDOOR COIL.
  • Record ID : 1987-1147
  • Languages: English
  • Publication date: 1986
  • Source: Source: ASHRAE Trans.
    vol. 92; n. 1B; 827-842; 7 fig.; 3 tabl.; 17 ref.; discuss.
  • Document available for consultation in the library of the IIR headquarters only.

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