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Connecting solar to existing system?

Last Post 15 Nov 2008 10:46 AM by Alton. 6 Replies.

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jdebree

Basic Member

Posts:497

05 Nov 2008 04:50 PM
I've been thinking about augmenting my electric hot water with solar, more as an experiment than anything else. I've seen all kinds of home made collectors, and I know how most of the systems work, but I have a dumb question: How do I use the hot water collected on the roof to heat the water in my existing electric hot water heater? If I could open it up, I'd put a stainless steel heat exchanger inside. I'm not real keen on circulating the water directly through the collector, since this is an experiment for when I move to a colder climate, and would have to worry about freezing temps. I'd rather have a closed loop w/ anti-freeze circulating.

Alton

Veteran Member

Posts:2164

05 Nov 2008 05:11 PM
Have you considered using a double-walled heat exchanger?

Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period . 334 826-3979

jdebree

Basic Member

Posts:497

Alton

Veteran Member

Posts:2164

05 Nov 2008 07:50 PM
A double-wall liquid-to-liquid heat exchanger is normally used with a storage tank. This is one of the best ways to keep the potable water system from becoming contaminated with anti-freeze, etc. The hot water heater would pull solar heated water from the storage tank. For more info, google double-wall heat exchanger.

Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period . 334 826-3979

jdebree

Basic Member

Posts:497

06 Nov 2008 05:24 AM
If I'm getting this right- I would add an insulted storage tank with the heat exchanger inside, and this would become the 'cold' water supply for the electric unit? I was hoping to use the original heater for storage, but as I said, there's no way to get a heat exchanger inside. I would have to build a water heater from scratch to do that. Thanks for the input!

Dana1

Senior Member

Posts:6991

14 Nov 2008 05:32 PM
I'm in no way connected to these people, never seen one of these close-up, (so this is in no way an endorsement) but on the surface it appears to be a reasonably-well designed retrofit system designed to drop into an existing tank HW heater: http://www.butlersunsolutions.com/index.html The fact that it's SRCC rated and performs well enough to qualify for the various rebates, etc. speaks well for it- it's probably way better than most backyard-tinkerer hacks. The self-regulating glycol loop is kinda kewl too. Seems exactly the type of system you envision, no?

Alton

Veteran Member

Posts:2164

15 Nov 2008 10:46 AM
jdebree, I believe you mean "insulated" instead of "insulted" storage tank. If so, there is an "Edit" feature that can be used after you post. On this forum we try not to insult people or storage tanks. Do not take me too seriously, I am just kidding. I guess I was a teacher for too many years.

Residential Designer & Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period . 334 826-3979