The performance of a photovoltaics (PV) panel is dependent on its surface temperature. Cooling the PV panel can substantially enhance its efficiency and thus the output power. Thermal management with spray cooling in porous nanochannels device offers a high heat flux removal capability due to thin-film evaporation occurring at micro/nano scale menisci. By integrating the nanochannels device on the back face of the PV panel, it is possible to dissipate heat from the PV panel so that it operates within a desired range of temperature values. In the present work, we utilize the results of spray cooling on such nanochannels device and perform the numerical investigation of PV panel cooling and enhancement in power output. A range of solar irradiation 500–900 W/cm2 is considered and the transient state transport equation for energy balance is solved numerically for 6 cases. With the applied thermal management using nanochannels device, the power output of PV panel is enhanced by ∼27% for the maximum solar irradiation of 900 W/cm2.