Overhead Heat Exchangers
Generally, a heat exchanger of this type discharges air from the ceiling into the cold aisle whereas the exhaust air rises into the vents in the ceiling; in Close Coupled system cases, the units are positioned directly above the servers, making the cold air delivery and hot air return much more precise.
A system of this type, being positioned vertically, does not need further floor space in the room.
Closed-Loop Configuration
The Closed-Loop cooling typologies act independently from the room they are installed; the rack and the heat exchanger work exclusively with one another, creating an internal microclimate.
In Rack Cooling
The cooling system is adjoint to the server rack and both of them are completely sealed; the solid doors on the enclosure and In-Row Air Conditioners contain the air flow, directing cold air to the server inlet and exhaust air, by using fans, through the cooling coil.
The Close-Loop design allows a very focused cooling at rack level and it is possible to install very dense equipment disregarding the ambient environment, giving flexibility to use unconventional spaces to install the IT equipmen