Farmall 504
Member
Some of you may have heard about this, as there is a video on YT called "Citrus in the Snow". Check it out. But as well as his system works, it has been greatly improved upon by others.
It's a very inexpensive way to heat a greenhouse. It's Solar-Geo.
Dig a hole, the deeper the better. Most parts of the world at 8 feet deep are around 52 degrees. Dig it square, or rectangular, then cover with 4 or 6 mil plastic, across bottom and up the sides. Then install 6 inches of just regular old white Styrofoam, actually called expanded polystyrene I believe. Now you run pipe down one side, across the bottom, and back up the other side. They should be a foot apart and at least 2 layers, 3 or 4 is better. You terminate that pipe in boxes, (pipe can be schedule 40 or even drainage tile, if your water table isn't too high), at either end, then stick a duct fan on top of the box on one side, on the other side you run 6 or 8 inch pipe from the box up to the ceiling to make a plenum box. Turn on the fan and it pulls warmest air from the top of the greenhouse down through the ground, warming it, and out the fan into the greenhouse. By lining the box with Styrofoam you can actually warm the box way above 52 degrees. The fan I'm using are 24volt low draw, less than a dollar a day to run. I can keep the greenhouse at least 25 degrees warmer than outside temps. It's perfect for citrus as those trees don't mind going down near freezing, unlike some fruits and veggies. My greenhouse is just 20 x 20, but I have detailed plans for a 30 x 100 greenhouse. Could put a lot f dwarf orange, lemon, lime, clementine, avocado, etc. in there, and heat it for almost nothing, Compared to the big commercial greenhouses that spend 20K a month pumping heat into their's. The fans need to be able to turn the air over within a few minutes. Also, you line the back of the greenhouse with 6 inches of foam too. Mine is a just a pvc hoophouse situated so the ends are east and west, and what you would normally think of as sides are facing N and S. The north side gets covered in Styrofoam, as no growing rays come from that direction, and heat slides up the back wall and into the plenum. I'm using 2 ply plastic cover and they make fans now to pump air in between, that helps a lot too. So basically you keep it close to air tight and just recirculate the air. During the day the sun heats it up inside, and you pump that heat down into the ground. At night it pulls it out and warms. At 90 degrees in the greenhouse on a sunny day the air coming out of the fans is 50 something that's how much heat is staying in the ground. I'm not a big green guy at all. But this is really neat technology. The earth in my box is at 60 degrees. With outside temps at 20 degrees I can keep it at 50+ inside. Just moving air. I'll post some pics if anyone's interested.
It's a very inexpensive way to heat a greenhouse. It's Solar-Geo.
Dig a hole, the deeper the better. Most parts of the world at 8 feet deep are around 52 degrees. Dig it square, or rectangular, then cover with 4 or 6 mil plastic, across bottom and up the sides. Then install 6 inches of just regular old white Styrofoam, actually called expanded polystyrene I believe. Now you run pipe down one side, across the bottom, and back up the other side. They should be a foot apart and at least 2 layers, 3 or 4 is better. You terminate that pipe in boxes, (pipe can be schedule 40 or even drainage tile, if your water table isn't too high), at either end, then stick a duct fan on top of the box on one side, on the other side you run 6 or 8 inch pipe from the box up to the ceiling to make a plenum box. Turn on the fan and it pulls warmest air from the top of the greenhouse down through the ground, warming it, and out the fan into the greenhouse. By lining the box with Styrofoam you can actually warm the box way above 52 degrees. The fan I'm using are 24volt low draw, less than a dollar a day to run. I can keep the greenhouse at least 25 degrees warmer than outside temps. It's perfect for citrus as those trees don't mind going down near freezing, unlike some fruits and veggies. My greenhouse is just 20 x 20, but I have detailed plans for a 30 x 100 greenhouse. Could put a lot f dwarf orange, lemon, lime, clementine, avocado, etc. in there, and heat it for almost nothing, Compared to the big commercial greenhouses that spend 20K a month pumping heat into their's. The fans need to be able to turn the air over within a few minutes. Also, you line the back of the greenhouse with 6 inches of foam too. Mine is a just a pvc hoophouse situated so the ends are east and west, and what you would normally think of as sides are facing N and S. The north side gets covered in Styrofoam, as no growing rays come from that direction, and heat slides up the back wall and into the plenum. I'm using 2 ply plastic cover and they make fans now to pump air in between, that helps a lot too. So basically you keep it close to air tight and just recirculate the air. During the day the sun heats it up inside, and you pump that heat down into the ground. At night it pulls it out and warms. At 90 degrees in the greenhouse on a sunny day the air coming out of the fans is 50 something that's how much heat is staying in the ground. I'm not a big green guy at all. But this is really neat technology. The earth in my box is at 60 degrees. With outside temps at 20 degrees I can keep it at 50+ inside. Just moving air. I'll post some pics if anyone's interested.