An experimental study on a solar-assisted heat pump incorporated with PCM based thermal energy storage unit

Considering the storage of solar energy, which is intermittent in nature, and its usage even when it is absence, this study deals with the evaluation of thermal performance of a water-to-water heat pump (HP) system with a thermal energy storage (TES) unit integration. For this purpose, a TES unit is designed and integrated to a HP experimental rig. Different volume flow rates of the heat transfer fluid at the condenser side ( V = 400, 600, 800, 1000, and 1200 L/h) and water temperatures in the thermal storage tank (Tst = 35, 45, and 55 degrees C) were taken into account along with the consideration of phase change material (PCM). The temperature variations in the tank, total heating time, compressor operation time ratio, and coefficient of performance (COP) values are obtained from the experimental data and discussed accordingly. The results showed that the PCM inclusion can significantly improve the heating time up to 30.6% and COP up to 33.9% at Tst = 35 degrees C, while it can have an adverse impact at Tst = 55 degrees C. Besides, compressor operation time can be reduced by up to 16.5% at Tst = 35 degrees C, while it is increased by up to 15.7% at Tst = 55 degrees C. The trade-off between the sensible and latent heat storage is emphasized in the present work.