Refrigeration-COP values in different climates

[gentatsuki]

The carnot efficiency of the refrigerator is simply given by Tl/(Th-Tl).
Let's say we have a freezer and ambient temperature of 20 and 28 degrees celsius.
I varied the ambient temperature by plus minus 1 degree and found out that the COP varied by about 4 to 5 units.

I've read about refrigerators having different climate classes, but how then are refrigerators designed to handle the different ambient temperatures in climatic countries? What is the difference between a refrigerator meant to operate in let's say a tropical country compared to somewhere in UK?

 

[engnr_arsalan]

let say our objective for designing is to get optimum cop.
cop is function of Th(temp. of hot side) and Tc(temp of cold side)
Tc should be lower then what is desired for example 0°c but Th has a lower limit such that it should not be lower than outer atmospheric temperature in case of domestic refrigerators.so in order to get optimum Cop we can adjust Th and Tc by lowering and raising the temperatures respectively such that they don't get equal to ambient and freezer temperature..
cop increases as Tc increases and Th decreases (in case of refrigerator)
so refrigeration cycle is designed in such a way that pressures and corresponding temperatures fall in these limits while giving max cop.
i hope that this will clear some fog...