We're replacing 125 WSHPs at a building that are about 15 years old.
The EER is going from about 8.5 to 15, and the COP is going from 2.9 to
4.5. I would expect electric savings and a slight heating penalty for
the increase in COP, but I'm getting -20% heating penalty. Any help is
appreciated...
-Beka
Rebecca,
If the COP is getting better as you mention 2.9 to 4.5, wouldn't you be
saving heating electricity rather than getting a penalty?
Nick Couture, LEED AP
Beka,
What I have experienced is that more efficient equipment loose less energy into the air stream. So a premium efficient motor may save kWh's but slightly increase the gas usage because it has less heat contribution to supply air.
20% sounds excessive, but a closer look is needed to determine the actualities.
Kevin
Rebecca, one sanity check on that number is that the increase in natural gas energy should be about equivalent to the electrical energy saved on the compressors for heating due to the increase COP. If there is a lot of simultaneous heating and cooling going on, the penalty might be even larger since your cooling units are rejecting less heat to the loop. That should give you an idea if something fishy is going on.
Adam