Investigation of Enhanced Performance in Flexible Solar Cells Using Passive Cooling Technique

Abstract

The lack of flexibility and enormous weight in conventional photovoltaic (PV) modules limits their applications. The advantages of flexibility and lightweight have made flexible solar cells popular in various applications. However, flexible PVs have an efficiency degradation due to an increase in module temperature through incoming solar infrared radiation. Both the power output and the electrical efficiency of the PV module depend linearly on the operating temperature. For every degree increase in the PV temperature, the efficiency decreases by 0.45-0.65%. Here, the novel concept of applying a nanomaterial-based heat-resistant coating for the passive cooling of flexible solar cells was experimentally investigated. A heat-resistant coating generally keeps buildings cooled by filtering UV and infrared rays and transmitting visible rays. This approach works by controlling the incoming solar radiation, thereby decreasing the overall temperature of flexible solar cells passively without adding much weight. Here, a transparent flexible polyacrylic sheet 0.25 mm in thickness was used, and two coats of silver nanomaterial-based coating were applied. The sheet was placed over a flexible solar photovoltaic module with a power rating of 6 watts. The temperature of the flexible solar photovoltaic module was recorded at different time intervals for August, September, and October using temperature sensors, taking note of factors such as wind speed and solar irradiation. These readings were compared with those taken from the solar panel without any coating. A temperature reduction of 6-7°C and an improved solar power efficiency of 2.5-4 % were observed for cooled flexible solar panels.