Hello Mr. Yago,
I have been a subscriber for several years and I am now ready to put in a solar heater for my home.
I would like to know if I can use regular electric water heater tanks for my system safely, in a batch heater system? I am looking to put in three 80 to 120 gallon tanks, will they work okay if they are in good condition or should I go with pre-made solar tanks? I do not believe that I will have a problem with piping everything in with electric type of tanks if they will hold up.
Thank you for all of your helpful knowledge and information that you put out and thank you ahead of time if you get around to this mail. I realize you are busy.
Many people do make solar batch heaters out of used electric hot water tanks. Of course any used pressure vessel has a higher risk of failure and you must make sure you have code-listed temperature relief valves and pressure relief valves, and that they are properly sized for each tank.
The downside of using these used electric tanks is they are “glass” lined and most solar hot water tanks are “stone” lined. You want to store the solar hot water as hot as possible and a glass lined tank is more likely to crack at these higher temperatures which is why solar tanks use a heavier and higher temperature rated lining.