Quote:
Originally Posted by buffalobillpatrick
Thanks Steve,
Your data shows about a 2% loss of HP efficiency for each *C increase of load temp.
So keeping a load tank 15*C hotter to handle "design temp" winter night
vs. a mild Fall day,
would cost about 30% in HP efficiency.
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I'm not sure about your numbers, it may be correct, but don't forget the time lag of a high mass floor. The ODR system is watching the temps and they don't usually fall or rise up that quickly. There will always be some under or over shoot. There are PID algorithms that can be written into the controller to account for the rate of change in outdoor temp. They would be a bit house specific, I think.
There are saving to be had for sure. With boilers, the industry sort of agrees on a 10% fuel savings. I don't see why an ODR motorized mix valve just for the floor loops would be an issue. The tank would be depleted more slowly so the HP would not come on as much.