Comparison of the operation performance of split and integrated type air source heat pump water heater via modelling and simulation

Modelling and simulating the performance of air source heat pump water heaters can guarantee better operation and routine maintenance of the system. The primary data used in the development of the models were collected from data acquisition system that was designed and employed to monitor the COP of installed 150 L integrated and split type ASHP water heaters under three scenarios of controlled volume of hot water drawn off. The study presents both mathematical models and simulation application developed for the COP of the two systems; using the temperature difference of the refrigerant at the compressor suction and discharge ends, the temperature difference of the refrigerant at the inlet and outlet of the condenser, the ambient temperature and the relative humidity as predictors. The results revealed that the split type performed better than the integrated type with significant difference in both summer and winter with a p-value of 1.34 × 10-10 and 0.0167, respectively. In addition, the derived models for the both systems had very good predictions for both the trained and validated dataset with determination coefficient of over 0.9. Furthermore, heat pump manufacturers and energy service company can easily use the derived models in the developed two dimensional multi-contour simulation plots and the simulation applications to show the variation and the impact of the COP with the various predictors for both systems.