MORE WAYS TO RECYCLE OLD REFRIGERATORS INTO LOW COST SOLAR WATER HEATERS

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The only real problem with that idea, of course, is that exchanger tanks are expensive ($170 and up) and hard to locate. Which is why MOTHER's deucedly clever inventors didn't even bother trying to find a ready-made exchanger tank to buy.

Instead, they went down to the warehouse/workshop of the local natural gas utility (United Cities Gas) and asked for one of the "worn-out" gas-fired water heaters that such companies frequently sell as scrap. And the folks at UCG were nice enough to lay such a tank on MOTHER's men for free.

Now one of the nice things about the "worn-out" water heater tanks which the various gas companies around this continent discard ... is the fact that a good many of those tanks aren't really worn out at all. They're merely defective. The containers leak water all right, but not necessarily because they've rusted through. And if you remove the sheet metal "wrapper" and fiberglass insulation from the basic tank itself ... you'll very often find that the container is only leaking from one small pinhole on a single seam which was never welded quite right when the container was put together in the first place. Such a hole is very easy to "patch" with just a tiny spot weld.

Another very nice thing about these discarded gas-fired water heater tanks is the exhaust stack that extends right through each one of the drums, from its bottom all the way up to its top. This stack was originally designed to transfer heat from a gas flame (burning inside the stack) to the water in the surrounding tank. It's very obvious, then, that if you plumb one of these heater tanks up and run solar-heated hot antifreeze through its stack ... you'll stand a very good chance of transferring large quantities of heat from the central pipeful of circulating antifreeze to the water surrounding it.

Which is just what our boys had in mind. And which is just what they did. The conversion was made by welding one two-inch pipe coupling into the top of the water heater tank's exhaust stack and another into the stack's bottom. A two-inch- to- three- quarter- inch reducing bushing was then screwed into each of the couplings and standard 3/4" copper tubing and fittings attached to the bushings. Presto! A $170 exchanger tank was ours for slightly over $5.00 In hardware and a couple of hours of our time.

At this point we could have put the original meager insulation and sheet metal wrapper back on the exchanger tank ... but we wanted something much better. So we built a plywood box big enough to give the tank a good six inches of clearance all around when set down inside the wooden box ... and completely filled the space surrounding the drum with MOTHER's good ole homemade cellulose insulation (see "How to Make and Install Your Own Insulation", pages 120—121, MOTHER NO. 48).

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