Solid CO2 is used as a refrigerant.
Solid CO2 is also known as Dry ice.
Have you seen the artificial clouds in movies?
It is noting but Dry ice (solid CO2)
Dry CO2 gas is pressurized at 50-60 atm and refrigerated between −57∘C and+30∘C until it liquefies. Next the pressure is reduced to (~35) atm. As a result some liquid CO2vapourises, causing a rapid lowering of the temperature of the remaining liquid. As a result, extreme cold causes liquid to solidify into a snow-like consistency. Finally, the snow-like CO2 is compressed into either small pellets or larger block of dry ice.
⇒ It is used as a refrigerant