ML-11-023 -- Empirical Modeling of a Rolling-Piston Compressor Heat Pump for Predictive Control in Low-Lift Cooling ✓ Most Recent

This paper describes the measurement and empirical modeling of the performance of an inverter-driven variable capacity rolling-piston compressor heat pump for use in a predictive control algorithm to achieve energy-efficient low-lift heat pump operation. A 0.75 ton (9,000 Btu/h [2.64 kW]) heat pump was tested at 131 steady-state operating conditions, spanning pressure ratios from 1.2 to 4.8. Compressor speed, condenser fan speed, condenser air inlet temperature, and evaporator air inlet temperature were varied to map the performance of the heat pump over a broad range of conditions, including low-pressure ratios. Empirical, regression-based, curve-fit models of the heat pump power consumption, cooling capacity, and coefficient of performance were identified that accurately represent heat pump performance over the full range of test conditions. This model can be incorporated into model-based predictive chiller control algorithms, where compressor speed and condenser fan speed can be tuned to achieve energy-efficient low-lift chiller performance.