Understanding mechanisms of snow removal from photovoltaic modules

Snow accumulation on photovoltaic (PV) modules causes major economic losses by reducing/preventing solar energy production. To develop mitigation strategies for snow accumulation issues on the PV modules, it is crucial to understand various snow removal mechanisms from them. Here, natural snow accumulation and its removal from the PV modules were investigated over two years using a surface-mountable sensor that measures liquid water content (LWC) at the interface of snow and module's surface real-time. It was found that the snow removal from the PV modules occurs under four distinct categories: melting, shedding (fast sliding), prolonged melting, and melting followed by shedding. During snow melting, the average LWC of snow and the module's surface temperature increased gradually (13.45%/hr and 0.81 degrees C/hr), while during snow shedding the average LWC and surface temperature sharply increased (14.4%/hr and 1.46 degrees C/hr). During prolonged melting, the average LWC of snow slowly increased during the day (4 average LWC slopes were 5.88, 3.22, 6.18, and 7.92%/hr), and the module's surface temperature reached 0 degrees C for a very short period of time, then decreased back to freezing temperatures at night. Lastly, the final snow removal mechanism is melting followed by shedding, during which the average LWC of snow increased gradually indication of snow melting (LWC of 11.25%/hr), followed by a very sharp increase in LWC with an average rate of similar to 83.02%/hr, after which snow shedding occurred. These understanding provide means to develop a combined passive and active mitigation strategy for efficient snow removal from the photovoltaic modules.