air water cooling
In many cases, the power dissipation of processors and blades exceeds the specified heat generation in racks. To avoid failures and malfunctions, combined cooling concepts with air-water cooling with heat exchanger (LWWT) have been developed in the meantime.
The advantage of air-water technology is that water, relative to volume, has a specific heat capacity approx. 4,000 times higher than air, and is better suited for heat dissipation and cooling of critical components. The higher density of water allows much more heat to be removed from a cabinet.
Air-to-water heat exchangers use two separate circuits: an air circuit and a water circuit. In this method, the internal air in the cabinet is circulated and transfers its thermal energy to the heat exchanger. The heat exchangers mounted on the side walls extract the heat from the indoor air and transfer it to the chilled water via the external liquid circuit.
The capacity of such modular systems can dissipate 20 kilowatts (kW) or more in a rack and achieve air circulation of several thousand cbm/h. Cooling by means of air-water heat exchangers is specified in DINIEC 62454.
For an air conditioning capacity of 500 kW, providers rely on cold water cooling, chilled water( CW). With this technology, heat is dissipated via a mixture of water and glycol.