Subterranean Heating and Cooling System "The SHCS relies on a hybrid earthtube and rock bed latent heat storage system. The system uses a matrix of four inch slotted pipe buried in a rock bed that is constructed under the greenhouse structure. The total volume of greenhouse air is circulated through the pipe matrix 5 times per hour at a flow rate of 2 to 4 feet per second and latent heat is stored in the rockbed. This is a very innovative process in that it uses additional heat energy released during the phase change from water vapor to liquid. The SHCS will be used year round to help maintain a more constant temperature in the greenhouse." If a temperature differential in the 20-30F range is maintained between the rock bed and the water vapor saturated greenhouse air, phase change occurs and heat energy is released and stored in the greenhouse rockbed foundation. The SHSC system pays for itself by significantly reducing the amount of fossil fuel derived heat used in cold weather crop production."
Duct Fan			Exhaust Plenum