DOE EERE Research Reports

Heat pumps lose efficiency when frost forms on the outdoor coil during heating-mode operation impeding heat transfer and adding to the work done by the fan motor to drive air across the heat exchanger. More energy is lost when the heat pumps goes into a defrost cycle to melt the accumulated frost and ice. Then, even more losses occur every time the compressor and fans cycle off because the thermostat has come up, or down, to the set-point temperature. Studies have been conducted to quantify these dynamic losses while operating heat pumps in order to better understand their significance and to aid in designing a future generation of equipment with lower frosting, defrosting, and cycling losses than those in currently available systems.

1. Air-Source Heat Pump: Field Measurement of Cycling, Frosting, and Defrosting Losses, 1981-83
2. Frosting Experiments for a Heat Pump Having a One-Row Spine-Fin Outdoor Coil
3. A Frost-Less Heat Pump
4. Laboratory Evaluation of the Heating Capacity and Efficiency of a High-Efficiency Air-to-Air Heat Pump with Emphasis on Frosting/Defrosting Operation
5. The Laboratory Evaluation of the Heating Mode Part-Load Operation of an Air-to-Air Heat Pump
6. Laboratory Examination and Seasonal Analysis of Frosting and Defrosting for an Air-to-Air Heat Pump
7. Laboratory Examination and Seasonal Analysis of the Dynamic Losses for a Continuously Variable-Speed Heat Pump
8. Laboratory Study of the Dynamic Losses of a Single Speed, Split System Air-to-Air Heat Pump Having Tube and Plate Fin Heat Exchangers
9. Performance Evaluation of a Low-First-Cost, Three-Ton, Air-to-Air Heat Pump in the Heating Mode
10. Performance Evaluation of a Selected Three-Ton Air-to-Air Heat Pump in the Heating Mode