Optimization study on the performance of a thermosyphon-based radiative cooler

By comparison with cool roofs, the cooling energy produced by radiative cooling can be stored in hybrid radiative cooling air conditioning (HRcAc) systems, which is more feasible for the application of radiative cooling. A thermosyphon mainly relies on buoyancy to drive the water circulating in a pipe without a pump and has been widely used in solar thermal collectors. Thus, more cooling benefits can be achieved by integrating a thermosyphon with HRcAc. This paper investigated the cooling performance of a thermosyphon-based radiative cooler (STRC). The STRC was modelled by using OpenModelica to derive the effects of structure parameters on the cooling performance. The optimized structure was determined according to the proposed optimization process. Finally, the cooling energy saving potential and economics for the application of the STRC in a single-floor family house in five climate zones of China were evaluated. The results show that the annual cooling electricity consumption can be reduced by 41%–56% and that the simple payback period for a single-floor family house with an optimized STRC in all five climate zones of China is between approximately 8.4 years and 10.5 years.