Abstract
When a photovoltaic (PV) array is installed at a roof, the snow on the array and the roof needs to be removed not only to reduce the snow load but also to effectively utilize the solar system. If dc current is flowed through each PV module from a power supply, the surface of it was surely heated, to assist snow sliding on the array. In the electrically heating system, snow sliding at the array needs to be detected to turn the system off and to generate the electric power by the solar system. In the preliminary tests for snow sliding, the instance of snow sliding on the PV array which consists of ten PV panels was identified by the VTR pictures taken every one minute during the tests. To find out the event of snow sliding over the PV panel, the time variation of temperature at the under surface of the PV panel measured at intervals of ten minutes was investigated in detail. It was revealed that the temperature at the under surface of the array always rose above 3°C at least whenever snow slid at the PV panel.
