Advances in Heat Pump Modulation

ABSTRACT New Technologies are available and are in the process of commercialization which will dramatically change conventional residential heat pumps. These technologies involve the use of scroll compressors, utilization of inverter-driven brushless permanent magnet motors, and adoption of microprocessor-based ASICs and “Smart Power” I.C.s for modulation and system control. Various approaches allow utilizing these technologies to modulate such system parameters as capacity, dehumidification, duct air temperature, air flow, and efficiency in response to system loading in order to improve total system performance. The driving force for acceptance of these technologies in Japan, where they have already become established, is increased comfort. During the 90's, comfort and the desire for increased energy efficiency will lead to the commercialization of the concepts in Europe and the United States, as well as further development worldwide. This paper will focus on the application of these technologies to split system heat pumps in the two to five ton range which are typical of the U.S. residential heat pump market. However, the results and conclusions are broadly applicable to other types of systems as well.