Sustainable Low-Cost Heating for Season Extension Structures Clinch Appalachian Farmers Enterprise (CAFÉ)

CAFÉ CAFÉ is a member-run organization of 20 farmers growing mainly for public school and restaurant markets. CAFÉ is a member-run organization of 20 farmers growing mainly for public school and restaurant markets. In , CAFÉ conducted trainings and research in order to explore low-cost sustainable heating alternatives for greenhouses and hoophouses. In , CAFÉ conducted trainings and research in order to explore low-cost sustainable heating alternatives for greenhouses and hoophouses.

Composting CAFÉ found that composting added an insignificant amount of heat to the interior of the greenhouse. CAFÉ found that composting added an insignificant amount of heat to the interior of the greenhouse.

Geothermal Energy Geothermal energy only differentiated the temperature inside the hoophouse by about 10 degrees; a well built, double- walled greenhouse is already likely to be eight degrees warmer than the outside air, meaning a gain of only 2 degrees, at considerable expense. Geothermal energy only differentiated the temperature inside the hoophouse by about 10 degrees; a well built, double- walled greenhouse is already likely to be eight degrees warmer than the outside air, meaning a gain of only 2 degrees, at considerable expense.

Heat Sink The area required for sufficient heat sink material is so large that the growing area in a normal sized greenhouse would be greatly reduced. The temperature gains would not be worth the loss of production. The area required for sufficient heat sink material is so large that the growing area in a normal sized greenhouse would be greatly reduced. The temperature gains would not be worth the loss of production.

Insulating the North Side of the Greenhouse CAFÉ members tried banking bales of leaves against the north side and north- west corner of a greenhouse, but temperatures inside the structure actually dropped, though the plants growing there were unaffected. CAFÉ members tried banking bales of leaves against the north side and north- west corner of a greenhouse, but temperatures inside the structure actually dropped, though the plants growing there were unaffected.

Low Tunnels in High Tunnels CAFÉ members the temperature inside the high tunnel was an average of 5.5 degrees warmer than outside, and that the temperature inside the low tunnel was an additional 4.9 degrees warmer, for a composite gain of 10.4 degrees for the low tunnel. CAFÉ members the temperature inside the high tunnel was an average of 5.5 degrees warmer than outside, and that the temperature inside the low tunnel was an additional 4.9 degrees warmer, for a composite gain of 10.4 degrees for the low tunnel.

Co-generation Heating CAFÉ found that this method of heating a greenhouse worked quite well, with temperatures ranging from 70 to 95 degrees (F), depending on fan-use and time of day. This would be a sustainable way to heat a hoophouse if the owner were already using wood fired heat for his or her home. CAFÉ found that this method of heating a greenhouse worked quite well, with temperatures ranging from 70 to 95 degrees (F), depending on fan-use and time of day. This would be a sustainable way to heat a hoophouse if the owner were already using wood fired heat for his or her home.

Double-walled Greenhouse Usually an effective sustainable heating strategy, CAFÉs experience with this technique was marred by problems with structural integrity. Double-walled greenhouses usually produce an extra 8 to 10 degrees of interior warmth. Usually an effective sustainable heating strategy, CAFÉs experience with this technique was marred by problems with structural integrity. Double-walled greenhouses usually produce an extra 8 to 10 degrees of interior warmth.