Scroll Compressors for Dedicated Heat Pumps: Development and Performance Comparison

Heat pump systems have to operate at high efficiency levels to be an economical alternative to the traditional heating systems. The requirements for the compressors are derived from the heating system design parameters (air or ground source) as well as from the ambient conditions which are not uniform through-out Europe. Therefore dedicated compressors were developed with adaptations to the standard air conditioning models to achieve the required coefficients of performance as well as the necessary operating range. Two types of scroll compressors for dedicated heat pumps are described in this paper. The first type is developed based on basic scroll design for an increased operating map and performance at high condensing. The second type of compressor for high condensing and low evaporation operation integrates an injection port to allow the heat pump to use a cycle with economizer. The main advantages are then a higher COP, increased operating map and higher capacity at low evaporation. These dedicated compressor designs make it possible to achieve the required high condensing temperatures. A performance comparison with the standard compressor designs is finally presented.