combination radiant floor and fan coil system

Langdon Sproul

Carol,
I'm involved in salvaging a solar thermal project (by others) that went south. Myself (engineer & C.E.M) along with a NAPCEP solar installer have come up with a solution lacking one attribute; providing a reasonable supply water temperature to both fan coil (150F-space heat) and the radiant floor manifold (120F) off a closed loop circuit controlled with a Takagi TK3 tankless water heater. We have a 45 gallon tank at 150F, but need to find a way to get the temperature down at the manifold. Being a closed loop, any additional cooling water metered in to reduce the temperature is problematic. The whole system is fed by a 3 panel, 2 80 gal. solar system. Any suggestions? As soon as the drawing is finished I can present it as well, if it would help.
Thanks,
Langdon Sproul

EricAune

Variable speed mixing

It sounds like the perfect spot for a variable speed injection circulator. I would use a Taco 00-VS circulator. The speed of the circulator is modulated to inject different temps from the high side into the cooler system return water. The PC board is built in.

Another option would be the 00-VR circulator. It is a outdoor reset.

Hope this helps.

http://www.floproteam.com/products/Wet Rotor Circulators/index.html?category=192

Peace

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