water heating for hydronic floors

Karl Molin

I have a viesman trimatik verticell gas heater with a vericell domestic water heat exchanger. Gas is very expensive. I also have a solar electrical array on my roof and have excess electricity. I am interested in considering the addition of an electric water heater to add heat to my gas heated hydronic floors and hot water system. How can this be done. I was thinking I would add the electric heater to the returning hot water coming out of the floor in a relatively cool state so as to assist the gas boiler.

Alan(CaliforniaRadiant)Forbes

I've had many

people call me who have photovoltaic collectors (cheap electricity) who want to install electric boilers to replace or amend their gas boilers, but no takers yet.

Have any of you guys installed one? In Karl's case, it sounds as though he wants to add an electric boiler to his exisiting system, presumably in series with his gas boiler with the return water first going through the electric boiler and then through the gas boiler.

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Rich W

pre-heat

I would use that power to pre-heat my DHW. You can find what you need here.

http://www.kansaswindpower.net/water_heaters.htm

hr

How much excess

PV electric do you have. I can't imagine you have spare kilowatts which would be needed to do much water heating, 1 Kw= 3412 BTU/hr.

hot rod

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ALH_4

Solar

PV is a much less efficient way to heat than solar hot water panels.

-Andrew

Rich W

cheap heat

If you have PV and no batteries then they just sit there wasting away with no load. A DC element to use that power is the least expensive way to do something with it. Yes, it's not the most efficient thing to do with PV. How efficient is using the panel for a big mirror to bounce the sunlight back to the sky? Without knowing the details of the system, it's tough to make a good decision.

Brad White_72

I agree with the other postings

and especially with the points that PV's are a tough way to predictably heat DHW. But DHW is the best repository of excess PV or solar or wind heat. IOW: I would not rely on it's availability but would "dump" the excess you are generating in that most useful of mediums. Radiant floors? Same deal.

I know of a local farm here in MA where the wind turbine and PV array take care of pumps, barn lighting and other basic needs and the excess goes to a preheat tank. Is that what your goal is?