Monday, June 9, 2014

Solar Hot water Round #2

So. last year, if you read our previous posts, we built a passive solar hot waterbread box for our hot water in the summer. And while it worked, it was just too far away from the shower, so by the time the water got back to the shower the tank filled up with cold water, it was just too far of a run. So we really only got a about one showers worth of hot water on a sunny day. and as soon as the sun went down the temperature of the water in the tank dropped immediatly.

So this year my husband built a solar hot water collector. Which is actually a solar panel. Some people think of solar panels as the part that generates the electricity, but this is actually not true, that is called a solar module. A solar panels are actually water heating devices.

So we are going to do our best to explain to you  how we built our solar hot water panel.


- repurposed glass ( we used sliding glass door, you want something about that size , about 32x80", which is pretty good size) double paned is better
-some lumber to build a frame, treated 2x4's and treated plywood ( because this will be sittting outside on your roofe)

- some type of insulation , foam board insulation  to line the inside of your box

- a metal absorption plate, we used some repurposed metal roofing spray painted black

-spray paint, black, flat works best

- some type of copper tubing to build your heat exchanger, depending on size .. we got a couple peices of 3/4" pipe and also a few rolls of the soft copper refrigeration tubing.
( please note that there are many different ways to build an exhanger which will require different amounts of copper, fittings etc) we chose this method because I could drill holes in the 3/4" pipe and insert the small tubing braze around it to make like a ladder type effect

- temperature controller, ours is a a close on rise temperature controller. ours is a honeywell.

-fasteners, misc nuts and bolts and glues and caulk etc :)

- air vent

- pressure releif valve ( Very important, for safety issues!!!!)


We decided to keep our hot water storage tank (which is well insulated) so that way the water you heat up stay hotter longer.. so if the sun goes down you still have time to take a shower.. so its not connected anymore, its just a storage tank.
So first we built a box for the sliding glass door to sit on.

Then, we put blueboard insulation on the inside of that wooden box.

Then we put our metal roofing , cut to fit, and set on top of the insulation and then screwed it down.

Next we built our heat exchanger to fit inside of that box..
You can sodder or braze or the copper. Robb Chose to braze. it saved money on purchasing extra copper connectors etc..

once you build your heat exchanger you need to locate your air vent and your pressure temp relief valve at the highest point of your heat exchanger so that they operate correctly.

After the panel is built you can run your water lines to your storage tank, (our storage tank serves as a storage tank for our wood fired hot water in the winter as well) so all we had to do was put in some T's and a couple of extra valves and we were pretty much set.

Since our sytstem is shared with the wood fired system, we have a second temperature controller, which is split my a center off switch, so for example: on a SUNNY winter day, you can have wood fired hot water in the morning, switch the center off switch to the other position and finish it off with SOLAR hot water... which we arent sure how many of those days we will have, but we will see.

We also put in some T's and some valves a the lowest part of the system so we can drain the water from the exchanger during the cold winter months, so it doesn't freeze,

I hope this gives you some ideas and inspiration !!
Here are some photos to give you a better idea ! There are so many ways to do this, find what works for you and go for it!

The Cools


  1. Looks great! One of these has been on my mind for awhile. I doubt we'll ever be able to go 100% solar, but we can go solar where we're able.

  2. excellent! If you have any questions, please feel free to messageme! oh and it works great!!!! plenty of hot water!! :)

  3. This is a neat system! I work with a solar company (Edison Solar) that has recently been working a lot with off-grid hopefuls. Systems like these need to be created to bring down energy usage to a level where solar modules can cost-effectively take over the rest, so I am collecting ideas like this to share with people!

  4. Thank you so much for posting. I have been looking for something like panels for schools

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  6. I am so glad everyone Enjoyed! I will definetaly try to post more "off grid" how to's in my blog!! Thanks for reading!

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  8. Hot water is one of the highest utility cost in every household. So having a solar hot water system is really a huge help to home owners. Anyway, I’m amazed that you did all the installation by yourself. Some prefer to call a contractor to do the installation. But if you have the tools and the knowhow, then it shouldn't be a problem. How is it, btw? I hope it works perfectly.

    Johnie Schueller @ Terratek

  9. What are you plans for preventing freezing in winter? Nice job!

  10. Patent your setup...Ty for sharing your ideas & way of making it while saving money. Gives me hope that I'll be able to do this as well someday.
    Have a great safe new year!