Influence of vibration time on dust accumulation on PV panels that operate light posts

Dust accumulation on PV panels is a severe threat that greatly affects the energy yield of photovoltaic panels drastically, especially in the Middle East and North Africa region. A new technique consisting of a dust shield, an antistatic hydrophilic coating and a mechanical vibrator has been developed to mitigate dust on PV panels operating light posts. The role of the dust shield is to obstruct the wind which is the dust carrier. The role of the antistatic coating is to prevent the dust particles from adhering to the panel’s surface. The mechanical vibrator is attached at the backside of the PV panel in order to shake off the deposited dust particles and fall off by gravity. Two experiments have been conducted, in the first experiment the impact of increasing the rotational speed of the mechanical vibrator on the amplitude of vibration was investigated, and it was found that increasing the rotational speed increases the amplitude of vibration, consequently, decreases the dust accumulation rate. On the other hand, the influence of increasing the vibration time on the dust accumulation rate has been investigated in the second experiment. This experiment consists of three PV panels mounted on a light post; the first panel is a reference panel for comparison, while the other two panels consist of a dust shield, an antistatic hydrophilic coating and a mechanical vibrator operating for 2 min and 4 min, respectively. The percentage drop in efficiency after 6 weeks of operation in case of the reference panel and vibrating the PV panel for 2 min and 4 min, are 19.02%, 13.75% and 11.14%, respectively. Therefore, vibrating the PV panel for 2 min and 4 min has decreased the percentage drop in efficiency by 27% and 41%, as compared to the reference panel. Moreover, the maintenance time, in case of the 2 min and 4 min of vibrations, is one and two weeks more than the reference panel, which indicates the effectiveness of the vibration time on the developed dust mitigation technique on PV panels operating light posts

Enhancing the performance of photovoltaic panels by water cooling

The objective of the research is to minimize the amount of water and electrical energy needed for cooling of the solar panels, especially in hot arid regions, e.g., desert areas in Egypt. A cooling system has been developed based on water spraying of PV panels. A mathematical model has been used to determine when to start cooling of the PV panels as the temperature of the panels reaches the maximum allowable temperature (MAT). A cooling model has been developed to determine how long it takes to cool down the PV panels to its normal operating temperature, i.e., 35 °C, based on the proposed cooling system. Both models, the heating rate model and the cooling rate model, are validated experimentally. Based on the heating and cooling rate models, it is found that the PV panels yield the highest output energy if cooling of the panels starts when the temperature of the PV panels reaches a maximum allowable temperature (MAT) of 45 °C. The MAT is a compromise temperature between the output energy from the PV panels and the energy needed for cooling