Performance of a Solar Greenhouse under Manitoba's Winter Weather Conditions

The performance of a solar energy greenhouse, which has been efficiently used in China to grow vegetables and flowers during the wintertime, was investigated under cold Manitoba weather conditions. A 30 m by 7 m solar greenhouse was constructed in Elie, MB. The greenhouse was oriented due south to absorb maximum solar energy, and had a north wall to store solar energy at daytime and release thermal energy at nighttime. The preliminary data showed that the application of solar greenhouse under Manitoba's winter weather was promising. During the month of February the daytime temperature inside the greenhouse was above 15°C and the nighttime temperature stayed above 0°C when the outdoor temperature was as low as - 30°C. Moreover, the comparison between the solar greenhouse and a conventional greenhouse showed that the solar greenhouse was 20°C warmer than the conventional one at night when the outdoor temperature was about -15°C. Without supplemental heating, vegetable seeds geminated well (95% in two weeks) in the solar greenhouse in February, and bedding plants (geraniums) grew well in March.