So I'm aware of systems to 'pre heat' inlet water in a storage tank, but I was hoping to do something a little more direct.I was wondering if there are any gas-fired hot water tanks that have a secondary 'hole' that I could put an electric DC heating element in. I would hook that element up to a solar PV panel or three directly, and let the sun make that tank nice and toasty during the day. Just take whatever hits the panels, totally unregulated, and direct it to warm the tank. Because it would go way above safe temperature, I'd put a thermostatic mixer (mixes hot and cold) to regulate outlet to a safe temp. There's already going to be a pressure-safe vent valve on the system in case it hits boiling point (though my energy input calculations seem to keep that from happening).Is this nuts? It seems like a really uncomplicated way to put solar to work.Bonus points if there are gas-fired hot water tanks with a second hole for an electric element and a way for me to run a copper coil through so I can recirculate hot water through a baseboard; it would be perfect for those days when I don't want to fire the steam boiler all the way up, but could use a few thousand BTUs to warm things up. via /r/DIY https://ift.tt/2PK3EPo
