'CAP' Controlled Air Path

Removing hot air from each cabinet by ducting the air through funnels on the top of the cabinet - in a controlled manner through the ceiling plenum - is a logical, simple and highly cost effective improvement to managing data centre cooling.

It meets the demand for greater efficiency in CRAC-based systems and helps to overcome the higher heat loads and increased packaging densities that have led to hot spots and recirculation issues - so saving money, improving reliability and reducing downtime.

The ColdLogik CAP system, both passive and active models, converts the cabinet into a ducted exhaust enclosure.

The unit is mounted on the top of the cabinet and connected to a dropped ceiling plenum, this isolates the hot air return path, prevents air recirculation and improves energy efficiency.

A CAP system can help future proof an infrastructure investment by allowing an upgrade from passive to active units - this enables higher heat loads to be added to the cabinets without compromising the data centre design.


Side view of a cabinet showing the path taken by hot air from the back of the cabinet through an active CAP unit and into the ceiling plenum

An active ColdLogik CAP controlled air path duct unit on a 42U high USystems 4210 cabinet

An active ColdLogik CAP unit fitted with three fan units.



The standard CAP unit is a passive system that relies solely upon the computer room air conditioning to draw the air away from the cabinet and into the ceiling plenum.

To assist the transfer of hot exhaust air into the plenum, you can upgrade the passive system to an active CAP system by replacing a panel in the front of the passive unit with up to three self-contained fan cassettes, each with a purpose designed controller.

To gain the full benefit of the CAP system – active or passive – you should use the 4210 sealing kit and, if there are gaps between active or passive 19 inch equipment, quick-fit blanking panels. The 4210 server cabinet will then be a heavy duty server cabinet with an efficient front-to-top airflow management system.


The active CAP system can be ordered pre-configured or by upgrading a previously installed passive CAP. Either one, two or three fans (with purpose designed controllers) can be fitted – depending upon your airflow and duty requirements – to assist the transfer of hot exhaust air into the plenum. A panel in the front of the main duct of the passive unit is replaced with the self-contained fan cassettes and, if required, blanking plates. The cassettes are fitted vertically – if only one or two are being used, they can be fitted left, middle or right to suit your requirements.



The passive ColdLogik CAP unit which can be retrofitted with cassettes as or when required.


An active ColdLogik CAP unit fitted with one fan unit and two blanking panels. An active ColdLogik CAP unit fitted with two fan units and one blanking panel.  Purpose designed controllers are included in each fan cassette

Typical air path within a data centre with CAP units deployed





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