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Forum Index : Electronics : Convert A/C system to Direct Current.
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| adric22 Regular Member  Joined: 06/08/2008 Location: United StatesPosts: 47 |
This is a theory of mine. I've been trying to figure out how to make the best use of my future wind/solar setup. It seems to me that 90% of my home's power usage is for the heating and A/C. If I don't want to buy an expensive grid-tie inverter, it seems the best way to make use of the power generated at home would be to put it towards heating or cooling. Since I do not believe I could generate enough power to run the A/C system or heater, I was thinking I could take a small window-unit air conditioner and convert it to run off direct current. My current line of thinking for a DC window unit is that if there wasn't enough amps coming in to keep it running full-speed, it would still be cooling, just not as well. I know that a typical window unit can consume 1,000 watts or more, but I was thinking if I could supply it 500 or more watts, it should still be able to cool some. During the winter I could channel the power into a portable space-heater. Being that it is just resistance, any amout of power should create some heat. Any thoughts on this? |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5012 |
Hi Adric This is an interesting project. A few things come to mind. First up, the compressor used in these A/C systems is a sealed unit ( black blob with wires and tubes coming out ), it would be difficult to convert to DC. Maybe there are DC compressors you could use, like those from the more expensive 12v portable fridges. Another option would be a compressor from a small passenger car, driven by an electric motor. The fan itself is relatively easy to convert to DC, just find a suitable DC motor ( Go see your local auto electrician, they use 12v motors with a shaft out each end for truck air conditioning units ) and rig it up to the existing fans. Moving that much air only needs a couple of amps. Or you could use a underground heat dump. Bury a length of poly pipe a few feet down in the ground, connect it to the evaporator ( or use a can radiator ) of the air conditioner and use a 12v fountain pump to circulate water through the system. A system like this would only use a few amps, and provide some cooling, though not as good a a true A/C unit. Remember the gas used in early A/C units is real bad for the environment, make sure you get it properly de-gassed/recovered before you start tinkering. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| adric22 Regular Member Joined: 06/08/2008 Location: United StatesPosts: 47 |
I went out to Wal Mart and bought a unit today for $89 to experiment with. The thing is amazingly simple inside. The fan motor is really not an issue. If all else fails, I could use a bunch of 12V computer case fans and mount them. hehehe. There are two main problems that I can see. 1) The compressor is, as you say, completely welded shut. I really had no idea it would be this way because I'm used to the ones in automobiles. I could use my dremel and cut the weld off to get access to the inside, but I'm not sure what I'd find in there and don't know if it is worth the time to find out. I do have a welder and I could weld it back closed again, so that isn't a problem. But I do not know if I'd be able to convert the electric motor to run on 12V DC. I could always rewind the motor, but I suspect it is an AC only motor and would complicate things. 2) There are no service ports for the refrigerant. They just crimped the end of the copper pipe to hold it in. I could cut the pipe and let the stuff out, but as you say, it is R22 and it is bad for the ozone. I don't see any way to reclaim the stuff properly. Once removing it, I could solder on a service port, so re-filling it wouldn't be a problem. Just getting it out seems to be it. So, I'm thinking I may have to find an alternative for the compressor. that was a good idea of yours, to look for 12V refrigerators. I bet I could use the pump from one of those. I also thought about using one from an automobile, but I'm not sure there is enough room inside this thing for both that and the appropriately sized motor to run it. |
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