Two ways to cool your Off Grid home from the summer heat using a basic geothermal cooling system. The ability to cool your home with the Earths natural cool temperatures is likely easier then you may have initially thought.
About 5 – 6 feet below the surface of the Earth the temperature is a constant 50 degrees F all year round. This cooler temperature can be used to cool your home efficiently.
Basic Geothermal Open Cooling System:
Image of a typical HVAC Booster Fan
A simply plan of laying 4 inch PVC pipe in a trench in the ground dug to a minimum depth of 5 feet (60 inches). One end of the pipe remains open above the ground, and at this end I’d suggest leaving 12 to 24″ of pipe above ground level to avoid rain run off filling your open pipe system. Additionally, a screen or wire mesh should be used to cap the end to avoid bugs, rodents, or debris from entering the pipe. The pipe angles down into the earth to a depth of about 5 or 6 feet. In the middle section of the pipe, add a few small holes 1/4″ to 1/2″ for drainage, in that mid section of the trench lay some gravel or pee stone underneath the pipe. Angle the pipe back up to the surface right next to your home and bring it inside.
Use a fan inside the home to pull air through the pipe. For this I’d recommend one of may different HVAC booster fans.
The fan will draw air in through the open screened end of the pipe and travel along the length of the pipe, during its travel the air will be cooled. Ideally, a 50 degree F air will enter your home, and begin cooling it. However, results may vary based on the amount of air being drawn through the open, the initial temperature of the air being pulled into the open pipe, and the length of distance the air had to travel through the pipe to the house. This is the most efficient version of geothermal cooling because all it requires is a fan to move the air once it is built. The length of pipe you use would depend on the size of your home and the size of your yard.
Closed Loop Geothermal Cooling System (Horizontal Loop):
Another version of geothermal cooling system uses buried water tubing under the ground. This system is a bit more complex and costs a little more but is a lot more efficient in energy transfer.
You can use coils of hose or run it back and forth in your yard. Bury it about 5 feet deep or more. The length of tubing depends on the size of your home. More would be better. In this case you will need a water pump to move the water through the tubing. A radiator is needed inside the home with a fan to blow air through the radiator. The water pump circulates water through the tubing. As the water passes through the buried tubing, it picks up the cooler temperature under the Earth. The water flows through the radiator in your home and a fan blows cold air, cooling your house.
Other suggestions for Geothermal Cooling Systems are:
- Vertical Cooling Loop
- Water Coupled Cooling Loop
Sourced: The Off Grid Projects
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