DC-83-13-2 -- A High-Efficiency Heat Pump Fan PDF

This paper documents efforts toward development of a high-efficiency outdoor air mover for an advanced electric heat pump. The design goal was to halve the outdoor air-moving electrical power. The prototype air mover at 850 rpm delivers 3070 scfm (1449 L/s) through the prototype outdoor unit with a pressure drop through the coil of 0.09 in. (2.29 mm) of water and consumes 150 W of electrical power. The overall air-moving efficiency is estimated at about 35% compared with 19% for the conventionally applied heat pump fan. Although this air mover will cost twice as much as the conventional heat pump air mover, this premium cost should be recoverable in less than four years through energy savings. The sound rating (SRN) for this air mover is less than 20. Means have been identified for improving fan efficiency by 5 percentage points and motor efficiency by 2.5 points and to further quiet the fan.