-40 °C cooling by CO2
An ambient temperature of 50 to 60 °C?? What country are you in??
Air refrigeration units using CO2 as a refrigerant are indeed available. All you have to do is use the Google search engine to find some. Try:
If you want to retain me to make a search for you, e-mail me at mbeychok@coxNO SPAM.net (remove NO SPAM).