SubscribeLiquid-cooled server racks from Knürr: The Miracel CoolTherm® platform provides heat exchangers with 10 kW to 20 kW within a closed cooling system (air to water).
In comparison with conventional air-cooled server racks which ensure the maximum amount of air throughput using perforated doors, Knürr CoolTherm® racks are completely sealed off from room air (IP55). Heat is dissipated via an air-to-water heat exchanger in the base area or door of the rack, which is connected to the cold water system in the building. Redundant high-performance fans drive a closed cold air circulation in the rack's interior. The built-in servers are supplied from the front with air that is brought to the right temperature of 20-25°C (68°F to 77°C) A cold water system with a chiller is required in the building for the operation of the rack.
There are no requirements for room thermal management; the rack system is fully independent of room air. The controlled airflow inside enables the evenly distributed cool air supply for all servers, regardless of their installation position in the rack.
The top server is cooled exactly as much as the lowest. For example a water cooled rack with 15 kW heat dissipated means a surface area saving of more than a factor 3 compared with conventional room management ! Apart from the heat exchanger, the user will find a perfectly normal 19" server rack.
Air-water heat exchanger The Knürr CoolTherm® rack application is for servers that do not require any special preparation, as well as for other heat-emitting components (memory units, TFT drawers, switches, routers, power supplies, etc) and for cabling, and so on. All previously usual access options with reconfiguration, maintenance, and repair are possible without any change; the Knürr CoolTherm® can also be operated with the doors opened (rear door for only a short period of time).
A comprehensive safety concept ensures a maximum amount of operational reliability and availability. All relevant components are, of course operated redundantly and connected to a redundant power supply.
Fans, temperatures sensors, door locks, smoke accumulation and optionally leaking water are monitored in the rack for dew point. Because of the way the heat exchanger is constructed, leakages and condensation build-up are ruled out anyway.
The heat exchanger is a compact unit with no detachable connections, which is pressured at production with 32 bars (435psi). This value lies well above the operational pressures that can be expected.
For the building network there are only two connections that can be detached, which, proven in building technology, also ensure compactness that can be controlled. The position of the heat exchanger right at the bottom of the rack, from where, in the worst scenario, water cannot get to the server area, provides additional safety. Should condensation build up in the heat exchanger with fall below the dew point, it is removed from the air-flow and diverted because of the structure design.
The CTU, which takes over all of the functions of the cold water supply and functions monitoring of a rack suite (5-10 racks), provides the maximum amount of safety possible. In addition to the function of a controlled interface, the option is also available here of completely separating the subsystem from the rest of the water system via a heat exchanger, and consequently ruling out large leakage volumes.
Because the rack interior is wellsealed against the room air, this cooling system provides exceptional protection against the effects of a fire. Smoke, aggressive gases, steam and extinguishing water are safely held back. As long as the cold water supply functions, even significantly increased room air temperatures are not a problem.
