Circulation Pump?

[rememberthemagic]

I have a large 80 gallon stainless steel tank that I have mounted in a large insulated cabinet with a glass lid. The theory is the sun will heat the tank/water and I can then use this to preheat the water going to the actual electric hot water heater in the house. Assuming it heats up the water even 10 degrees more than the 58 degree water we have now I have accomplished my goals. The question becomes this, do I need a circulation pump? At the moment I have the electric hot water heater plumbed as you would in any normal home. I have replaced the drain in the bottom of the hot water heater with a Hybrid Solar Water Heater Bottom Feed Connector, they have them on Amazon the ASIN # is B0041XRUK0 so if I use this it essentially creates a loop from the outside tank to the hot water heater using the utilities cold water to push water thru the tank, then hotter water out to feed the bottom inlet on the cold water side of the bottom feed connector. Will this suffice or will the pressure balance and no water will flow without a pump?

[ButchDeal]

I have a large 80 gallon stainless steel tank that I have mounted in a large insulated cabinet with a glass lid. The theory is the sun will heat the tank/water and I can then use this to preheat the water going to the actual electric hot water heater in the house. Assuming it heats up the water even 10 degrees more than the 58 degree water we have now I have accomplished my goals. The question becomes this, do I need a circulation pump? At the moment I have the electric hot water heater plumbed as you would in any normal home. I have replaced the drain in the bottom of the hot water heater with a Hybrid Solar Water Heater Bottom Feed Connector, they have them on Amazon the ASIN # is B0041XRUK0 so if I use this it essentially creates a loop from the outside tank to the hot water heater using the utilities cold water to push water thru the tank, then hotter water out to feed the bottom inlet on the cold water side of the bottom feed connector. Will this suffice or will the pressure balance and no water will flow without a pump?

I don't think you want to circulate the water form your electric water heater to the solar heater, as the electric water heater is going to be hotter.

What you want to do is run the fresh water into the bottom of the solar tank, then from the top, to the inlet of the water heater. This will warm the fresh water.
you should also paint the stainless steel tank black.

I did this exact thing in late '80s at a summer camp. Mounted the tank on a 30degree tilt, painted it black and ran the water through it.
they didn't run out of water after that.

[gmanInPA]

If you follow what ButchDeal is advising, you'll probably accomplish what you're looking to do and more efficiently than the HX idea. What ButchDeal is referring to, some would call a "tempering tank". If you want to circulate water through an H2O tank through a heat exchanger without actually mixing the water from the SS tank with your domestic water - you could potentially use a thermo-syphon - so long as your hot water tank is above the SS tank so that as the heated water rises into the hot water tank's HX and the cold water returns to SS tank. This could potentially negate the need of a circulation pump. If it were me and I did the latter, I would make sure there was a safely plumbed pressure relief valve in such a loop, and a way to drain the lines. I'd also make a way to shut it off in the colder months when it's likely not to help much.

[rememberthemagic]

Udate on this, almost 2 years later I did back in 2016 what ButchDeal suggested and in combination with a one way valve the system worked flawlessly.

[C_Heath]

Udate on this, almost 2 years later I did back in 2016 what ButchDeal suggested and in combination with a one way valve the system worked flawlessly.

Can you estimate a monthly savings to cover your labor and expenses? I just replaced a 22 year old electric AO smith 40 gallon tank with a 50 gal AO smith Heat pump water heater. I have started tearing into the old one and was planning on doing the same thing but it is going to be a tough job getting this old tank out of the skin. I mean tough! I have about 2 hours into it now and still have yet to get the metal outer casing off because of the thick foam. My heat pump water heater only costs $114 to run per year. At that rate I wonder just how much more I could save. I want to do it tho!

Thanks!