A way out offers the natural cryogen carbon dioxide (CO₂): it can be easily extracted out of the atmosphere and is released again there. Moreover, carbon dioxide is available at a low price world-wide. Simply is also maintenance and service of air-conditioning systems since CO₂ does not have to be recycled.

The company Konvekta AG develops CO₂-based systems for transportation of fresh or frozen goods. First prototypes proved to being fully operative on the test stand as well as during the three-year practice test in a refrigerated delivery vehicle of a supermarket chain. It turned out that carbon dioxide respecting cooling capacity and efficiency is competitive. The CO₂-prototypes ran reliably more than 5,000 compressor operating hours and 600 hours in the delivery cycle of fresh and frozen goods.

In comparison to conventional systems, the CO₂-emissions of the new refrigeration systems were up to 50 % lower. The expansion to a 2-stage system promises further efficiency increases for the use in transport refrigeration.

In temperate climate zones, the use of carbon dioxide in refrigeration units for fresh or frozen goods is an ecological alternative to that of conventional
HFC-cryogens like «R134a», «R 404A» and «R 410A». Crucial advantages are the low greenhouse potential, favourable eco-balances during manufacturing and waste disposal and the world-wide availability of CO₂.