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Photovoltaic Array Icing and Snow Accumulation: A Study of a Passive Melting Technology

Michael M.D. Ross and Eric P. Usher
CANMET Energy Diversification Research Laboratory

Full Text of Article
Link to CETC-Varennes
Link to SESCI (conference)

Note on Authorship:

This article was co-authored by the principal of RER Renewable Energy Research when he was an employee of the CEDRL (now known as CETC-Varennes).


Funding for this project was provided by CETC-Varennes through the Panel on Energy Research and Development (PERD), Canada's Green Plan, and the Science Institute of the Northwest Territories (SINT) as part of the joint NRCan/SINT "PV for the North" programme.


Ross, M. M. D, and E. P. Usher. "Photovoltaic Array Icing and Snow Accumulation: A Study of a Passive Melting Technology". Proceedings of the 21st Annual Conference of the Solar Energy Society of Canada, Toronto, Ontario, Canada: October 31 to November 2, 1995, pp. 21-26.


In Canada, after the least sunny months of the year, the reserve capacity of a PV system's batteries may be at its lowest acceptable state-of-charge. At this point, the risk of complete system failure is high if snow or ice accumulation prevents the panels from collecting any available solar radiation. To address this problem, a passive snow-removal technology has been developed by TN Conseil, working in conjunction with the Energy Diversification Research Laboratory (EDRL) and the Institut de recherche d'Hydro-Québec (IREQ). This paper introduces the problem of snow and ice accumulation on PV panels, describes the solution proposed by TN Conseil, and presents results from outdoor testing and mathematical modelling conducted at the EDRL.

The TN Conseil technology consists of a stagnating thermal air collector mounted on the rear face of a standard PV panel. Thermal models of PV panels with and without the TN Conseil technology have been developed and used to determine panel surface temperature and snow and ice melting rates under various conditions. These thermal models have also been used to investigate whether panels equipped with this technology can charge batteries during the summer months. Since the TN Conseil technology makes use of ground-reflected radiation incident on the rear face of the panel, a radiation model which accounts for the shading of the ground by the array was also developed.

It was found that the most problematic form of snow or ice accumulation is rime, an opaque ice that can form on PV panels situated near mountain tops and along mountain ridges. Monitoring and mathematical modelling suggest that the TN Conseil technology should reduce the time required for a panel to clear itself of snow by 80 to 95 % and rime by 20 to 40 % under typical winter conditions