| In much of Canada internal heating for buildings is required for over 70% of the year. Solar energy has the potential to significantly reduce the consumption of non-renewable resources used for heating, while also having a substantial economic benefit. The Canadian climate poses freezing difficulties when using liquid collectors, Using air as the working fluid has the advantage of a simpler design. Solar air heating is already established for applications such as fruit drying, crop drying, green house heating, and space heating.; Conventional solar air heaters operate with efficiencies between 40--50%. The present solar collector was experimentally tested outdoors, operating with an average efficiency of approximately 85%. The high efficiency is achieved using a porous medium to absorb solar energy and by preheating the air before entering the second pass of the collector. The collector proves that it is possible to utilize solar energy for heating buildings efficiently and economically. |
