Originally Posted by
desA
In my heat-pump trials, I have observed an influence on evaporator SH, due to ambient air temperature movements.
If Ta,in falls during the range of test, SH will roll down a little more than if Ta,in is constant.
If Ta,in rises during the range of test, SH can often end up being almost constant over the test duration.
The influence can be in the range of ~ 1-3K, depending on the operating SH of the machine.