Energy conservation by ventilating a greenhouse with deep-mine air

Use of deep-mine air to heat or cool a greenhouse has the potential to reduce significantly the energy required for environmental control. The environment is also potentially well suited for growth of many greenhouse crops. Temperatures within the greenhouse were generally maintained at 10–13°C during the night and 16–24°C during the day when solar energy was available. The relative humidity remained at 100% day and night during cloudy weather and fell as low as 40–50% on days of high solar intensity. In addition, the carbon dioxide concentration was near 2400 mg 1^?1 throughout the year.Flowering bedding-plants and vegetable transplants of high quality were produced during the spring season. High - quality lettuce was produced throughout most of the year. The production time of all crops was equal to that of crops grown commercially in the area.