Radiative cooling-assisted thermoelectric refrigeration and power systems: Coupling properties and parametric optimization

A CP2–127–06 Melcor module is incorporated into a radiative cooling (RC) system to work as a thermoelectric refrigerator (TER) at daytime and a thermoelectric generator (TEG) in nighttime. Through analysis of the single RC system, only a small temperature span between environment and building can be achieved. However, the temperature span can be significantly improved by combining RC and TER. The TER's input electrical current is optimized to obtain the maximum coefficient of performance (COP) 4.85 and the maximum cooling power density (CPD) 9.64 × 10³ W m⁻². Making trade-off between COP and CPD, the optimal regions of the COP, CPD, temperatures of cold side and hot side, and electrical current are determined. Further, the RC-TEG system's maximum power density 5.10 W m⁻² and maximum efficiency 0.369% and the corresponding optimal conditions are obtained. With increasing the area ratio of emitter to TER or TEG, the performances of the systems are firstly improved and then remain almost unchanged. This work may provide guidance for building's thermal management at daytime and power generation in nighttime.