A Novel Study on Energy Storage Potential of an All-Day Radiative Sky Cooling Radiator Assisted by U-Shaped Ground Heat Exchanger

Practical utilization of radiative sky cooling (RSC) in an active way to produce cooled fluid breaks the passive cooling limitation of 150 W/m2 but requires considerate system design. For this circumstance, this work proposes a hybrid radiative sky cooling radiator (URS) system assisted by the ground heat exchanger (GHEs) and explores the activity application of RSC based upon a simple hybrid system while fully considering the weather effects. First, the influences of designing, and operation parameters on cooling capacity are explored based on the developed system and hourly-based meteorological data. Then the annual variations of system performance are evaluated systematically. Moreover, the differences in the spectral properties of different radiative coolers on the cooling capacity are also clarified. The results show that the smaller flow rate (0.02–0.06 kg/s) benefits the RSCR module’s total cold generation with a maximum of 2.1 kW on annually average. After being assisted by GHE with high-temperature outlets, the heat convection on the RSCR side is dramatically improved, resulting in net cooling power soaring to over 450 kWh/m2. As the URS continues to operate, the performance of the whole system gets better, due to the improvement of the heat convection on the RSCR side. As cooling demand increases significantly in the current days, this work provides an effective way for better utilizing radiative sky cooling with energy saving, water saving, and high energy efficiency.