This paper addresses a low complexity and high efficient cooling system applicable on photovoltaic (PV) system leading to enhance electrical efficiency and provide preheated water. The developed system consists of a photovoltaic panel, a cooling water system establishing a uniform surface temperature, and a solar water heater. According to the proposed system characteristics, the setup is constructed based on a single mono-crystalline solar panel to absorb more solar radiation intensity and generate more electrical energy per area in compare to a poly-crystalline panel. The preheated water produced by absorbed heat from the photovoltaic is conducted to a solar water heater to satisfy domestic hot water demand. The experimental results show the electrical, thermal and overall energy efficiencies are boosted to 12.3%, 49.4%, and 61.7%, respectively. The results are obtained on July in Tehran, Iran. Moreover, comparing the performance of the cooling system with the conventional systems reveals that the proposed system has higher efficiency originated from the uniform minute holes in the implemented shower stuck on the panel back. Furthermore, if the heat transferred to water in the cooling system is utilized, the payback period is estimated 1.7 years; otherwise, the payback period exceeds 8.7 years if only PV conversion efficiency is included. (C) 2018 Elsevier Ltd. All rights reserved.