Why does my more-efficient GSHP have lower tank temperatures?
The image below shows two model runs, both with a 2.5 kW GSHP. The 2014 one has a CoP of 2.14 and the 2040 one a CoP of 2.41. Other than that the systems are identical. The only other difference between the runs is that the external temperatures have been increased in the 2040 EPW.
The power (labelled energy) seems right, but for some reason the water tank temperatures are consistently lower in the run with the higher CoP and external temperatures.
What could I check to try and figure out the root cause of this difference?
Are the two heat Pump system sizes identical - or both autosized? The higher ambient air temperatures may lead to reduced Heat Pump has less capacity - or at least a different response from the same Heat Pump object.
@TomB some of the fields are autosized. But how does the ambient air temperature affect the GSHP?