A Couple DIY Solar Thermal Ideas For You

I didn’t go to engineering school, but I love engineering and prototyping. I love thinking about systems, how to maximize output (or whatever your goal is) depending on the constraints whether it be space, time, or money. From concept, to design, actually building it, and then making adjustments for the following versions based on what you learned.

For the past 2 months I’ve been living on my friends farm in Maine. When our oil furnace died, so too did our hot water. We needed to quickly figure out how to create hot water. Our design parameters?

1. It needed to work, most of the time
2. It needed to be super cheaper, meaning it cost less then $500 to make and nothing to run
3. And we needed to be able to build it quickly as we had dishes pilling up and were sick of boiling water.

We came up with utilizing the wood stoves free heat during the winter and harvesting BTUs from the sun in the summer.

During the winter

The whole space is heated with wood, so we drilled through the back of the stove and put a heatexchanger in the stove. The thermocyphins with the 30 gallon storage tank which is teed into the cold line coming from the street. It works amazing, during the winter when the stove is running we have plenty of hot water. Note, these type of systems are 100% “illegal” and you shouldn’t install them on any clients house. However, up here in Maine, everyone has them and they work just fine. You just need to make sure you have blow-off valves in the proper places in case it gets too hot.

In the summer

We created a “tank in a box” that costs us $100 and about 2 hours to make from some wood scraps and fiberglass batt. Again, we teed it into the existing system. It creates plenty off hot water, takes about 2 hours in solid sun to heat up and holds the heat a few hours after the sun has set.

Here are the pros and cons of the system