Performance analysis of passive cooling for photovoltaic modules and estimation of energy-saving potential

Photovoltaic (PV) cooling techniques focus on the conversion efficiency of PV modules. Unlike active cooling techniques, which consume more energy, selective spectral cooling and passive radiative cooling are based on the principle of suppressing heating by the PV module itself. In this study, a thermal-electric coupled model is established for evaluating the cooling effect of selective spectral and passive radiative cooling under variable conditions. Compared with referenced PV modules, under conditions of AM1.5, v = 2 m/s, T-a = 309.15 K, selective spectral, passive radiative, and combined cooling could promote the efficiency by 0.98%, 2.40%, and 4.55%, respectively. Based on the proposed model, the potentials of passive radiative cooling are theoretically estimated by considering differences in relative humidity for different locations around China, and potential improvements of efficiency by 2-2.5% in the northwest and northeast could be estimated. In addition, the levelized cost of electricity (LCOE) was used to clear the economic viability of the proposed passive cooling methods, and the integrated energy-saving efficiency (IESE) was proposed to quantify the gains of power generation and the shading performance.