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EDR calculations at different temperatures
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Brad White_9
Member Posts: 2,440
Dave is right Radiation is not heat loss.
As Dave said, knowing your heat loss is primary; knowing your radiation is secondary and tells you how lucky you probably are to run "X" temperature on a design day.
As for derating, (assuming that your starting point of 170 degree average water temperature yields 150 BTUH per SF right?) it is this easy:
Subtract 20 BTU's per EDR for every 10 degree drop in average water temperature, assuming a 70 degree room.
So your 150 BTUH at 170 degree AWT becomes:
130 BTUH @ 160F AWT
110 BTUH @ 150F AWT, etc. etc.
Down to 10 BTUH @ 100F AWT
As Dave said, knowing your heat loss is primary; knowing your radiation is secondary and tells you how lucky you probably are to run "X" temperature on a design day.
As for derating, (assuming that your starting point of 170 degree average water temperature yields 150 BTUH per SF right?) it is this easy:
Subtract 20 BTU's per EDR for every 10 degree drop in average water temperature, assuming a 70 degree room.
So your 150 BTUH at 170 degree AWT becomes:
130 BTUH @ 160F AWT
110 BTUH @ 150F AWT, etc. etc.
Down to 10 BTUH @ 100F AWT
0
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EDR calculations at different temperatures
Hello,
I have done a total EDR calculation based upon the data I found on this webpage at an avg temp of 170F. If the avg temp in my system is less than 170F, how do I do the calculation? Is there an equation or another table at different temperatures?
Thanks.0 
edr graph
Here is something you might use.
If I attached it correctly.0 
Be very careful here,
I would be "very leery" of sizing a HW replacement boiler by the existing EDR alone,,,the only real accuracy is in doing a room by room heatloss calculation. That way you`ll know the exact water temp. you need in these (possibly now) oversized rads.
Dave0 
0 
graph
Don't see it Unless of course my glasses are still dirty0
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