Low operating costs and total reliability for computer centres. Use of highly efficient adiabatic recooling systems.

Recoolingsystem LUMI - RKS 600-2, glycol free

The high performance computer centre Green Cube in Salzburg is Austria’s largest computer centre with place for 10.000 servers over 2000m² of technical area.  Virtually 100% of the electricity which flow into the servers is converted into heating.  Based on these grounds, it was crucial to implement a highly efficient cooling technology which with the least possible energy consumption the warmth in the environment to dissipate outside.  Looking at the cost-effectiveness it is crucial to use recooling system, which is low in maintenance but with a high level of reliability.  Both requirements can only be met by a modern, highly efficient LUMI-Recooling system, which enables 100% adiabatic mode of operation.   the Green IT principle constructed Green Cube is therefore equipped with two highly efficient recooling systems which boast a high level of reliability as well as low maintenance requirements.

The systems are equipped with LUMI – pressurized water humidifiers for adiabatic cooling of the outside air to the web-bulb temperature.  In this way, the free cooling is possible over a longer period of time.  In this time frame, energy intensive and expensive provision of machine produced cooling can be avoided.
For an energetic and optimal operating with maximal free cooling, the system is glycol free.  Two deciding factors led to this decision - the minimal viscosity of water as opposed to a mixture of water and glycol and therefore the minimal energy consumption of the colling circuit pumps as well as a better transfer of heat of the water as opposed to the glycol/water mix.  One requirement for the use of such a system is frost protection.  Therefore the systems are equipped with front protection.  Both LUMI-Recooling systems, each with 570 kW recooling capacity stand on the roof of the computer centre.

Owner: conova communications Ltd
Planer: RFG Engineering Ltd  


Design of the Recooling System

Special features

  • Free cooling at a medium temperature of 17°/14° C
    (approx. 130kW) at an outside temperature up to 12°C

  • Cooling(adiabatic) at a medium temperature of 35°/27°C
    (approx. 200kW) at an outside air temperature up to22°C

Further References

  •     VR-Bank Sennfeld
  •     Clinical Center Würzburg
  •     Sovello Thalheim
  •     State Police Stuttgart
  •     Airrailcenter Frankfurt


  •     Control cabinet
  •     Frost protection system
  •     Double sided window shades
  •     High pressure humidification system with high pressure pumping station
  •     Double sided silencer
  •     Weather proof housing

Technical Details

Recooling capacity570 kW
Air temperature/ moisture inlet36,0 °C / 30 % room humidity
Wet-bulb temperature22,0 °C
Glycol content0,0 %
Cooling medium inlet/outlet35,0 °C / 30,0 °C
Dimensionsapprox. 9.000 mm x 3.800 mm x 2.700 mm
Operating weightapprox. 12.500 kg