there's a jacket of compressed CO2 around your intercooller when the hot intake charge heats the liquid CO2 it boils removing the heat from the intake air and through convection moves the hot gas CO2 to the cooler jacket of the intercooler to dissapate the heat the CO2 then retuns to a liquid to repeat the process.
A liquid can transport and hold heat more effectively than air, the liquid CO2 can hold ALOT of heat and move it fast but if you have to much heatgoing through the intercooler to vaporize all the CO2 or your not cooling it good enough then the jacket of CO2 will be like a blanket.. holding the heat in... it all depends on the design.
A good concept, but i'm not shure how much it will weigh, if the design is good enough it could be a more effective way to creat a colder intake charge efficiencies up to 90-95%(big guess).