An Investigation of the Contribution of Solar Energy in Heating Greenhouses in Quebec

Abstract

An experimental study on a commercial greenhouse in Montréal, Québec, was undertaken during the winter season, October 1971–April 1972. The object of the study was to determine the percentage of the heat load that is provided by solar energy during the winter season. It was found that the monthly average of solar energy thermal contribution varied from 13 to 54 percent, the rest of the heating load was, of course, supplied from a conventional fuel-fired furnace. It was seen that during the coldest part of the winter in Montréal the solar energy contributed very little toward the heating of the greenhouse and its main function was confined to that of triggering photosynthesis. It appears that there is a definite need of redesigning greenhouse structures in Québec such that the solar energy would play a larger role in heating them. This is necessitated because there is a need both to reduce the heating expenses and conserve fuel resources. The average cost of heating was found to be of the order of $5.00 per square meter of greenhouse.