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Forum Index : Solar : Any use for a dead AC?

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wallablack

Senior Member

Joined: 10/08/2011
Location: Australia
Posts: 164

Posted: 11:16am 23 Dec 2012

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My Air Conditioner broke down the other day....BUMMER!!! New one gets installed 1st week of Jan so praying for cooler weather.

It is a cheap TCL 8Kw. She has a fair size coil in it and I was wondering if these are any good to adapt to DIY solar hot water.

Foolproof systems do not take into account the ingenuity of fools.

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 04:36pm 07 Feb 2013

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wallablack

I just stumbled across this thread while surfing the index.

If you're talking about using either the condenser coil or the evaporator coil as a heat exchanger, yes, it will work, but I did this on my very first solar water heater and found no matter how much you flush things out, you still get a drop or two of compressor oil in the water. I ran cold water through the coil, which I had painted black and aimed at my southern sky (I live in US).

I think if I were to do this again, taking advantage of repurposing the 'pre-built' coil, I would paint things black, then run compressor oil inside the coil. At that point, using a soft-copper tube attached to the output side of the coil then wound around another copper pipe of larger diameter, the larger pipe being a part of a "loop" in a domestic water heating application, the heat would be transferred from the hot oil-filled system to the cold water-filled one. This way, the hot oil would never come in contact with the cold water and you'd be good to go. Both systems would need to be actively pumped.

I've done something similar and intend on doing it again come this summer, but my collector is MUCH simpler, however, repurposing stuff is always a good idea. I'll post my build on the 4m when it happens (June 2013?)

Best of luck.

. . . . . Mac

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

readyakira

Senior Member

Joined: 17/07/2008
Location: United States
Posts: 114

Posted: 10:09am 07 Mar 2013

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I would NEVER use it for hot water unless you plan on running a non-corrosive coolant thru it to a heat exchanger. I assume the coils are aluminum. I would think first like said above you will NEVER get all the compressor oil out. (very bad for your health) second as with most water, I'm sure yours has corrosive elements in it. Coils for AC tend to be thin and I would suspect it would not get the life you would want out of it. I have seen even copper get paper thin from some places here in the states with water that is not pure. My old panel (pre-built) copper had thin copper and I ended up throwing it to the recycle yard.

But that is just my two cents.

Don't you think Free/Renewable energy should be mandatory in new buildings?

Georgen
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Joined: 13/09/2011
Location: Australia
Posts: 462

Posted: 01:01pm 07 Mar 2013

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Non-corrosive liquid for particular metal would be good start.

My problem is efficiency as there has to be:

- air
-some kind of medium

-air again

and every heat exchange has only so much efficiency.
Suppose with free solar energy, we might accept excessive losses.

George

norcold

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Joined: 06/02/2011
Location: Australia
Posts: 670

Posted: 07:46am 08 Mar 2013

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Solarhart use an additive called Hartguard in their closed systems, you add 5 litres to rain water(or distilled water even better) in their 300l closed system. The closed systems have the collectors and a heat exchanger in their tanks isolated from your normal water supply. The closed systems are used where the normal water supply has mineralisation such as bore water.

We come from the land downunder.
Vic

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