8 Answers

Building a solar heat collector

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8 Answers

So I have 2 30 gallon barrels in my greenhouse for thermal mass storage. Soon it will be more consistently getting into the single digits so I need to have the water to be warmer going into the evening.

I am building a solar heat collector using 3/4 copper and a salvaged window and plumbing the barrels together. The goal will be hot water from the sun using 60 watts from the pump while the sun is out and radiating it into the greenhouse during the cold hours of the morning.

So far this is what I have for plumbing the barrels together.

building solar heat collector

solar heat collector

Gina Ask

If you can get backs off fridges or freezers they are black and make good heat exchanges

John Correia

If you're going to run nutrient solution through those you're going to cause oxidation with acidic nutrient solution and give your plants metal toxicity. If you have metal in contact with solution you should coat it with some neoprene S18 epoxy. If you…

John Correia

I suggest just running the water through a dark colored PVC or clear PVC in your window box. instead of using the copper pipe.

John Correia

This will work a lot better for plants. Hope this helps.

Chaney Gierhart

This is just for heating the greenhouse. No nutrient solution will be flowing through this set up. I could use a pex coil but the copper will have more surface area per unit of fluid per unit of time as well as having better heat transfer.

Chaney Gierhart

this is just for the radiant heating for the greenhouse. This will not be for nutrients. It will also be charged with glycol to prevent freezing as it will have some pipe in freeze prone locations and it gets below 0 here.

Chaney Gierhart

I do plumbing and radiant heating for a living and i am planning on having a very nice heating set up with very minimal power draw for over the winter.

Andrew Holding

I saw one where they took aluminum soda cans and removed the tops and bottoms where they still nested and epoxied them together. Then put it in a box sprayed black and connected them end to end. Placed facing south to get heat during the winter. You might be able to put some aluminized mylar (space blanket) inside the box to reflect the heat back at the pipes. Maybe even a one way mirror to let the rays in but not back out.

Ryan Gibson

Would love to see this set up when it's all done. I'm trying to figure a better way to heat my greenhouses through the winter. It rarley gets in the single digits usually teens here.

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Building a solar heat collector