Solar Heater for My Shop
Solar Heater for My Shop
After changing TV providers, I found myself with this extra wide Satellite dish. I thought "Boy that would make a great reflector for a solar oven." So I sprayed some adhesive on it and grabbed a Mylar "Space Blanket" out of my "Go bag" and covered the face of the dish wit it. Then pointed it at the sun, and put my hand just about where the LNB would have been. Ouch! I will not try that again!
Adding the "Black Box"
After some experimenting, I added a small black "key lock box". Then I was getting readings of well over 500 degrees F.(260C) So I figured anything I was cooking would be burnt on the outside before it was done on the inside.
My next thought was "If I add a coil of copper tubing, It should heat water pretty fast"
Coiled to strike! err, I mean heat.
Using some 1/4 inch copper tubing, I made two small coils inside the box, drilled a couple holes for the ends to pass through at the bottom. And stuffed fiberglass insulation behind them so they would stay in contact with the dish side of the box.
Adding pump and storage
I had a 20 pound propane tank (the kind used for grills) that had the valve broken off. I twisted the remainder out of the tank with a pipe wrench. Then filled it with water so I could drill and tap a second hole without fear of any lingering propane igniting. I found a nipple at my local hardware that fit the original hole. Inside this I epoxied a 3/8th inch "drop tube" to send the hot water to the bottom. The second hole that I had drilled near the top, I tapped for a 3/8th inch pipe fitting. This would become the "output fitting"
I then purchased a 12 volt DC 50 psi "beverage" pump and some 3/8th inch ID plastic tubing that I routed up to the coils on the dish and down to my pump and storage tank.
The Heat Exchanger
Being someone who keeps everything, (Much to my wife's dismay) I had a dead window air conditioner. After removing the cover, I decided the fan and outside heat exchanger would be about the right size. So I removed both and mounted them in an old PC case. (See I told you I never get rid of anything) I was able to leave the fan connected to the original control box after disconnecting the compressor wires. I the used my tubing cutter to cut the top and bottom copper tubes leading from the compressor.
My pump drawls from the top of this coil/heat exchanger and pumps to the up side of the dish coil. The down side or hot side attaches to the "drop tube" on the storage tank. The out put tube on the storage tank goes to the bottom of the fan/heat exchanger.
I point the dish at the sun, and turn the pump on for a bit before starting the fan. This heats the water in the storage tank quite quickly. Then when I turn on the fan, I get nice warm air out of my solar heater.
The photos above show first the room temperature, then the air temperature at my heater.
I have an old DisEqC rotor on the dish, I am working on a way to control it to automatically follow the sun, perhaps in my next Comment/How-to.
Have fun and stay warm!
Acknowledgments, Credits, and Bibliography