Quote Originally Posted by desA View Post
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.
In your heat pumps, the ambient air would be the air entering the evaporator. As I interpreted the posters question, I believe he was referring to the air entering the condenser.