Paper No 082 – Experimental and Mechanistic Numerical Analysis of a Variable Speed Residential Heat Pump Unit with an Expansion Work-Recovery Device – 13th IEA Heat Pump Conference, Jeju, Korea
In recent years, variable-speed heat pump systems for residential applications have gained significant attention in order to improve the part-load operations during heating and cooling seasons. A single-stage 5-ton (17.58 kW) heat pump unit with R-410A as a working fluid has been considered as a test case to assess the performance of a variable-speed rolling piston compressor. Moreover, the heat pump has been retrofitted with a prototype expansion work-recovery device to replace the conventional expansion valve for cooling mode. The heat pump performance has been tested extensively in a pair of psychrometric chambers. In order to facilitate future optimization of the system, a fully-mechanistic steady-state cycle model of the heat pump has been developed. In particular, the system model is based on a charge-sensitive approach with semi-empirical models for the compressor and the work-recovery device as well as detailed heat exchanger models. The cycle model has been validated and tuned with the experimental data collected. Future work is to utilize the validated mechanistic model for cycle optimization and charge sensitivity studies.