I know I'm estimating some of these numbers, but I have my WEL calculating the number of kwhs used per day by the system. It also calculates the number of btus extracted from the ground (485*loop-delta*gpm, I think). If I multiply kwhs by 3414, then divide that into the extracted btus, wouldn't that be estimated COP? My calcs are giving me a COP of 7...that can't be right. (I recall a discussion about this recently on the board, but the search function isn't working for me today...sorry!)

I display COP in real-time on my monitoring web page when my GSHP units are in heat mode (see http://www.welserver.com/WEL0043 ).

Here are the computations for COP, in WEL terminology:

3TOn = Run 3 (On/off sensor)
L2 = Pulse 4 (GSHP power sensor (all power, including pump)
G05 = (LWT sensor)
G06 = (EWT sensor)

GPM3TOn=3TOn*10.4 (water flow previously measured manually)
LD3T=G05-G06
LKBTUHOn3T=LD3T*GPM3TOn*0.5 (no anti-freeze)

L2Adj3T=L2*3TOn*0.003416-1.315 (subtract out pump power (in BTU) to match COP formula used by WaterFurnace)

N1=L2Adj3T-LKBTUHOn3T (N1 is simply a temporary, intermediate variable)
COP3T=N1/L2Adj3T

See an NTREG Project document for a chart showing that my units run around 5.0 COP (page 6), as WF advertises.

Hope this helps.

Best regards,

Bill

jonr and Engineer helped me recently. What I got was:
8.35 * GPM * delta_T * 60 = btu/hr from the well
or Q(Btu/hr) = (GPM)(499)(delta-T)


COP = hh / hw

I hope the experts will add on to this thread. I think it would be helpful...

This thread was also useful to me: http://hvac-talk.com/vbb/showthread.php?167380-How-to-Calculate-BTU-s-on-CHW-System
and this webpage: http://www.geojerry.com/calculatecopeer.html