Waterless cleaning technique for photovoltaic panels on dual-axis tracker

Abstract

Several soiling mitigation solutions and cleaning techniques have been developed to maintain high e ciency of photovoltaic (PV) panels. First of its kind, the investigation of the adaptability of the cleaning systems to solar trackers has been performed. The majority of these systems are dedicated to xed installations whereas only few systems that can be adapted to solar trackers as presented in the updated cleaning systems background. For this reason, this paper presents an innovative approach which consists of combining trackers with an integrated cleaning system that has been designed. Based on the conducted experimental study, a maximum of 7% in soiling losses has been found for the PV generator of 4 kWp equipped with a dual-axis tracker installed in Rabat-Morocco over almost one year. Consequently, a reduced cleaning prototype has been realized and tested to evaluate the energy recovery based on the performed cleaning. The automatic cleaning has presented a similar e ciency with the manual cleaning with a slight difference of 0.95 pp and an increase of energy of 11.5% in the arid region. Through the economic analysis carried out taking into account the gain in energy production, the automatic cleaning cost was 0.14 €/kWh. It has been found that the cleaning technique based on the telescopic arm would be more effective if the tracker is installed in an arid region where soiling is higher than Rabat. In this case the payback time of the cleaning solution is faster (8 to 9 years), hence its pro tability. Corrective cleaning Manual cleaningManual cleaning requires human resources (labor), material such as soft brushes for dry cleaning as well as water in the case of wet cleaning. Karcher (kaercher.com/us/) which is a company specialized in the cleaning products, has developed cleaning brushes made by natural and nylon bristles that avoid micro-scratches to be created on the solar glass surface. These brushes can be tted with air pressure cleaners.As bene ts, the manual cleaning is considered the most e cient method to recover PV performance and it can be performed whenever required (Gupta et al. 2019b). However, it requires high cost and water which is limited as well as scratches may be produced. According to the study of (Fernández-García et al. 2014), the use of demineralized water and a brush was the most effective compared with a jet of air or water with high pressure. The use of detergent is not required since it does not increase the effectiveness of cleaning.

Design of actuator motor acceleration model in dual axis tracker movement for stand-alone PV system

“…The use of an actuator that is integrated with a DC motor as a dual tracker produces a large torque [31], [32]. Therefore, modifications to the use of a battery charge controller module are made to make it more efficient in the use of energy used.…”