Self-cleaning of glass surface to maximize the PV cell efficiency

Abstract

Photovoltaic (PV) modules are widely used for harnessing solar energy which ensure maximum output when their glass surface is clean. However, PV modules are open to dust, grime and other contaminations which get deposited on their surface causing reduction in transmittance and hence their efficiency reduces. It is therefore required to clean the glass surface of PV modules time to time either manually by labor or using some special arrangements such as automated systems. However, these techniques are either laborious or require extra energy. Therefore, another solution to offset such complications is to use chemical coatings which ensure self-cleaning of glass surface by increasing water contact angle. In the present study, two types of water repellent chemicals (such as trimethylchlorosilane and hexamethyldisilazane) have been used to coat the glass surface using dip coating technique. The performance of such coated glass slides has been investigated using some important characterization techniques, such as finding transmittance by spectrophotometer and measuring water contact angle using a high resolution camera. Moreover, the self-cleaning effect has been observed using a microbalance to measure dust on coated glass exposed to open atmosphere and compared with uncoated glass. The results revealed that these coatings have increased the water contact angle up to 149% which reduces friction between the glass surface and water droplets. Moreover, the friction reduction helps in mobility of water droplets which in turn can easily carry out dust along with them, thus improving the efficiency of PV module.

Recent Improvements of the PV Solar Energy Generation Performance

“…The study notified that power generation efficiency decreased by dust accumulations on the PV solar module. The dust accumulation decreases by 2.73% to 4.4% on average energy per day [36]. The power output is inversely correlated to the dust layer.…”

“…The PV solar energy generation systems are affected by environmental and weather conditions. The environmental factors like shading, dust, humidity, and so on tend to block sunlight from reaching the PV arrays then they limited the capacity of the generating power of solar module, and they reduce the overall efficiency by 30% to 40%, especially in desert areas [35,36]. Therefore, the PV solar modules performance is hurted by environmental factors, and such factors are described in the Fig.…”

“…However, the dust accumulation on the surface of the solar panel's reduces the efficiency and life span [99]. Therefore, the cleaning techniques are classified as; Natural cleaning techniques, manual cleaning techniques, and automatic cleaning techniques [36]. The detailed classification of the cleaning techniques are described in the Fig.…”

“…For example, in desert areas, the wind will increase dust accumulation. Furthermore, heavy rain may not clean thoroughly, and it will make scratches on the surfaces of the module [36].…”

“…The self-cleaning technique is the best method to clean the PV solar modules surface. It uses self-cleaning Nanofilms, which means coating the chemicals on the PV solar module surfaces [36]. Self-cleaning techniques effectively remove the dust accumulation for a big tilt angle due to sliding down by the force of gravity [101].…”