Server cabinet technology with outstanding features to reduce data center energy costs and reduce CO2 emissions. For very high cooling capacities above 20 kW per rack only closed directly cooled racks function reliably technically and economically optimal. Because of the favorable properties such products are also already used for cooling capacities from 10 kW. In the CoolTherm is hermetic closed server rack with integrated heat exchanger. A closed air circuit in combination with an air / water heat exchangers offer the possibility of up to 35kW heat load to dissipate from a rack. Since all water supplies are housed beneath the IT level, the risk is due to water in the IT rack almost non-existent. The rack is closed on the air side, the cooling air is guided in a closed circuit at a fixed temperature set value before the air intake of the IT components. By strictly separating the cold from the warm side, the cooling air temperature is from top to bottom the same, there is inherently no hot spots, even at the highest cooling performance. Due to the continuous strict control of the cooling air, the very short air and integrated in the cabinet fan a very high cooling performance is achieved. The fans themselves are energy-optimized (fan wheels, EC motors), the heat exchanger is in heat transfer and flow resistance […Technical data truncated]