Hello, i am working on a frozen food storage project where we are looking on optimizing its ammonia refrigeration plant.
There are 5 storage rooms and each of them have 2 evaporators with direct cooling.
There are two 2-stage sabroe compressors working in parallel with cold gas intercooling.
And an air cooled condenser sitting on the roof of the building.
The condenser fans have EC motors with 50% and 100% speeds.

The plant is found in the north of Norway with colder temperatures most of the year.

My question comes to the condenser.

We will like the condensing temperature to float in relation to the ambient air, but with different given temperature approaches so that the condensing temperature ranges between 13C and 23C.

I have been told by a former university lecturer of mine that the temperature approach is a fixed value for condensers.

My question is can the temperature approach not be adjusted to different values ? Some examples can be 15C, 20C, 25C.

If yes how can this be done ?