Impact of Variable Speed Components on the Seasonal Performance of a Residential Air-Source Heat Pump Using a Low Power Inverter for PSC Motors

摘要

Heat pumps utilizing variable-speed compressors and other capacity control techniques offer significant seasonal efficiency improvements over traditional single-speed systems by reducing system cycling losses and corresponding system inefficiencies. However, the majority of residential heat pumps operated in the United States (US) utilize single-speed Permanent Split Capacitor (PSC) compressors and offer few capacity control options. This paper presents testing results of a novel electronic drive that enables the variable-speed control of conventionally single-speed PSC motors in compressors and outdoor fans using a low power inverter. The focus of this research is to optimize the cooling seasonal performance of a 2-ton (6,7 kW) off-the-shelf residential air-source heat pump after replacing its PSC scroll compressor with a PSC rotary compressor with the low power inverter installed to enable variable speed control of the PSC motors. The modified heat pump has been tested in the Ray W. Herrick Laboratories at Purdue University for Seasonal Energy Efficiency Rating (SEER). The results show that a SEER improvement of nearly 32,85% is possible using a low power inverter for the compressor, indoor fan and outdoor fan. Results of this optimization indicate a total SEER improvement of 39,47% is possible by changing from a PSC scroll compressor to a PSC rotary compressor and connecting the inverter to these components.