Performance analysis of a hybrid HVAC system consisting of a solar thermal collector and a radiative cooling panel

We proposed a hybrid heating, ventilation, and air-conditioning (HVAC) system that integrates a solar thermal collector and a radiative cooling panel as a heat source and a heat sink, respectively. The annual performance of the proposed system was analyzed for a single-family house and compared with that of the conventional solar-assisted heat pump (SAHP) and radiative-cooling-assited heat pump (RAHP) systems. We found that the seasonal coefficient of performance of the proposed system can be enhanced by 27.3% for cooling compared to the SAHP system in cold-dry climate and by 61.8% for heating compared to the RAHP system in hot-dry climate. The detailed analysis revealed that the sizes of the solar collector and the radiative cooling panel, and the total amount of water (i.e., working as a heat source or a heat sink for the proposed HVAC system) are the key parameters affecting the annual performance of the proposed HAHP system. By using an optimization technique, we showed that these parameters should be varied depending on climate zones for optimal operation. Interestingly, it was found that installing both solar collector and radiative cooing panel can be more efficient than the conventional systems regardless of climate conditions (i.e., cold-dry: Denver; hot-dry: Pheonix; and marine: Los Angeles). The sensitivity analysis of each parameter revealed that the annual power consumption is less sensitive to the tank water volume for cold-dry and hot-dry climates, but the tank volume becomes important for marine climate. For considered three locations, the proposed system was found to be able to reduce the annual power consumption by about 3%~29% as compared to the conventional RAHP or SAHP system.