Coil in Coil condensors and subcooling.

[Bernoulli]

I have a refrigeration plant fitted with coil in coil condensors. I have always found them to have excessive subcooling, in the region of 10-20 degrees C, even after I have just recharged the plant with the correct gas charge and it is running at the design HP. I have eliminated air in the system as a cause, so does anyone have any idea whether this is a quirk of this type of condensor, or is there amother possible cause? As an aside, I also have a small A/C plant that has the same condensors and also has siimilar degrees of subcooling. In both cases the condensors are fed with seawater and HP is controlled by way of Penn valves.
Yours, hitting himself on the head with a hammer in order to make the thinking valve work, Bernoulli.

[NoNickName]

What is a coil in coil?

[US Iceman]

I am assuming it is a coaxial condenser. Or, it could be a vented double wall condenser.

[Peter_1]

The higher the SC, the better, so why worry.
It's normal when the condensor is oversized or when there's a subcooling section in an aircooled coil last coils at the bottom going up again)

[NoNickName]

The higher the SC, the better, so why worry.
It's normal when the condensor is oversized or when there's a subcooling section in an aircooled coil last coils at the bottom going up again)

Here our disagreement remains.
I have a typical example just a coupld of days ago. A two circuit chiller, 2x40 TR, air cooled with condensing fan speed regulation.
HP pressure regulated at 16.5-17 bar, with ambient at 10°C. Liquid temperature around 28°C, SC at around 17/18°K.
The performance of the chiller is well above nominal, thanks to high SC. Result = low pressure trip because of too high cooling capacity in the evaporator, TEV trying to cut the feeding.

[Peter_1]

Did once a calculation for a normal SC (5K) and then a more excessive one (18K): cooling capacity increased with +/- 13%
Plotting this out gave me an evaporating temperature drop from 1°C (chiller application I suppose) to -4°C (or +/- 5K).
Is this enough to trip the cutout safety switch?