Development of accurate and widely applicable compressor performance maps

Abstract

The compressor performance map provides critical information, including mass flow rate, power consumption, capacities, and operating current. The map can be applied to an alternative efficiency determination method (AEDM) for HVAC&R products. However, most of the existing maps have a low prediction accuracy under low ambient temperature heating modes, as such conditions were not thoroughly considered when maps were generated. This paper provides a comprehensive study of a fixed speed compressor performance under a wide range of operating conditions, including the AHRI 210/240 standard conditions. The test matrix was developed based on realistic heat pump system operating conditions. We then quantified the existing performance map’s prediction inaccuracy, particularly under the low ambient temperature heating modes. Driven by the significant deviation at lower ambient temperature conditions, a comprehensive performance map was generated based on the test results. We also found that one polynomial equation could simultaneously fulfill the needs for predicting the compressor performance under both the cooling and heating modes. Furthermore, the accuracy has improved significantly from 63% to 2% regarding the relative maximum prediction errors over existing performance maps. It suggests that to increase prediction accuracy when using the AEDM, one must provide a suitable superheat model in the capacity simulation of the heat pump systems with the fixed speed compressor.