Question about refrigerant charge

[A.Mortezania]

Hi All,

Would you please someone let me know :

Why when temp. of evaporator is low we must charge system with more refrigerant.
For example if a system working on air-conditioning system we must charge system with less refrigerant instead if that system works for example on -15C evaporator temperature.

Sincerely yours.

[Pop Alexandra]

I'm not sure what's the science behind it, but I've been always told to do so.

[frank]

Any system, high temp (A/C) or low temp should be charged to the correct suction superheat.
Different types or sized systems will have different charge amounts

[chemi-cool]

AC system will not operate well in low evaporating temp. You need a low temp compressor for that.