Capturing the Potential of the Sun

Cold soil reduces germination, inhibits plant growth, increases the incidences of root disease, and results in nutrient deficiencies.   Additionally, low night time air temperatures increase the risk of frost damage.

The solar thermal system helps solve these problems by heating the soil beneath the high tunnel.   Solar heated air from external flat plate collectors is circulated through corrugated drain tile buried in an insulated sand-based heat sink. The heated air warms both the soil and increases nighttime air temperatures.   At night the warmed soil continues to emit infrared radiation.  A second layer of plastic covering the high tunnel creates a pocket of air which is inflated by a fan, thereby trapping a sizable percentage of the emitted infrared radiation.  


Solar Thermal Heating