Climatological relevance to the soiling loss of photovoltaic modules

Dust accumulation on the Photovoltaic (PV) modules, or soiling, is one of the conditions that negatively affect the performance of the modules by obstructing and reducing the incident sunlight. The process of building up the soiling layer on the surface of the PV modules is heavily influenced by the climatological parameters. In this study, the soiling loss of 20° tilted PV modules, mounted on a mock rooftop at ASU-PRL, was monitored during dry and wet periods (May to July, 2014), and correlated with weather parameters and events. As a result of the experiment, Relative Humidity (RH) and Wind Speed (WS) are the major players affecting the soiling loss. Heavy rain acts as a cleaning agent while light rain could be either a cleaning agent or a soiling agent. Being typically followed by rainfall, dust storms in Mesa, AZ, are not sever soiling agents.