Why can't a refrigeration cycle with carbon dioxide as the refrigerant be made with conventional vapor compression?

Disadvantages of oversizing, unsuitability.

1, too large shortcomings: carbon dioxide as a refrigerant refrigeration cycle can not use conventional vapor compression system is because in the high temperature of the cooling water in the tropics, due to the critical temperature of CO2 is only 31.1 degrees Celsius, the use of conventional Perkin vapor compression refrigeration cycle when the loss of cold is large, and there is a saturation pressure is too high, the compressor power consumption is too large shortcomings.

2, not suitable: conventional vapor compression refrigeration cycle is not suitable for carbon dioxide as a refrigerant refrigeration cycle.