The air conditioning systems of Erich Keller AG are cooled not by compression cooling but by evaporating water. Freecooling is at least 10 times more efficient at cooling than conventional systems. All units therefore work with high-performance heat exchangers. The system components are precisely set-up in order to achieve the best possible efficiency and indoor comfort. The system for cooling the heat given off by IT equipment is conveniently integrated into the return. The waste heat released can be directly used for heating purposes. Up to 30% of the heating requirement is covered in this way.