toadshade
New Member
I am starting my research on building a solar water heater. My main question for now is the water storage container. I am a welder and appreciate steel or especially stainless steel but no matter how much I know how to build a stainless vessel, it is still extremely expensive. As of now my system will be an indirect (closed loop) glycol system heating the supply tank with a three way bypass with a tankless water heater in high demand situations. I plan on regulating the tank to 150 degrees F for now (adding more storage in the future if I am heating water that efficiently). So given those temperatures, I see no reason not to use a food grade polyethylene barrel for my storage container. The water will not be consumed so it is not a safety concern. A shower would be the only real contact and I do not, nor have I ever, drank my shower water ?. I will have a copper or stainless coil on the roof and I was thinking a PEX coil inside the container. And I will spray foam the container. As long as I can keep the storage container sealed, then I do not see any reason why I cannot use the food grade drum over a very very expensive stainless drum. I searched the forum for a little while assuming I could not be the first person to bring this up, but I could not find any discussion on this topic.