Using “junk” for Solar Water Heating Systems

On June 07, 2009 in General Information

I saw this post on Instructables called Solar Thermal Water Heater For Less Than Five Dollars

Obviously it is going to cost more than $5 to be able to actually use this for something, but I had never thought of using the coil from the back of a refrigerator as the tubing inside a flat plate collector before. Don’t get me wrong, I find junk laying around all over the place and love to think up ways to use it, this is just one piece of junk I hadn’t considered for a flat plate solar hot water collector.

They claim pretty decent heating with their not so great setup, so with some small improvements it would probably work quite decently. To do any decent scale I would probably connect a few of the coils in a parallel arrangement with headers of a larger diameter than the coils themselves.

Well reading about all that got the wheels in my head rolling and I ended up at this post on PhysicsForum about using a car radiator as a heat exchanger in a solar water heater setup. This particular setup was for preheating biodiesel to cut down on electricity costs during production, but had some excellent points. Unfortunately they never followed up with any results.

So then I stumbled over to this site about a Solar Water Heater made from a car radiator. This is also in a flat plate setup.  But of course they want you to spend money on some book rather than sharing information about it.

Well being put off by being asked to pay for access to information, I dug around some more and found this crazy long usenet forum post with lots of good info about solar water heaters, mostly related to using a car radiator as a solar collector.

From there I ended up at the Iowa Renewable Energy Association’s website where I found this little blurb about using a car radiator and a fan in a solar heating system:

“Storage of solar energy in water has been a proven method over many years. This water can be used as DHW, but also can be used to heat some or all of your house, garage, or workshop. To install enough solar panels and storage to heat an entire older home would be expensive, so most people try to do just some space heat. If your house is modern and very energy efficient, then solar could do a large part of your heating. An easy method is to install “kickspace heaters,” which can be as simple as a car radiator and a fan to distribute the heat from the water storage to one or two rooms.”

This info comes from their page on Solar Thermal but definitely check out the rest of the site as they have loads of good information.

Using recycled parts is great, especially in something like a solar water heater, and so stuff like this really makes me think. If anyone can think of any other relatively common objects/materials that can be repurposed for a solar heater (yeah we’ve all heard about the soda can heaters, and recycled pipe and fittings are awesome but hopefully most folks would think of that), leave a comment here on this post.

That’s all for now, just wanted to ramble about my thought process and the various places and things the internet can lead you to see and read about in a short period of time.

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