A device used to transfer heat energy from one medium to another. Common uses of heat exchangers are water to air heat exchangers in air handling units, plate and frame heat exchangers in economizers, etc.
Distortion in the line voltage waveform. Any cyclical waveform can be described as the sum of sine waves of various magnitudes which are integer multiples of the root frequency (60 Hz, 120 Hz, 180 Hz, etc.). Harmonics are often the result of the non-linear loading of the power distribution system due to the nature of solid state power supplies. Harmonics are detrimental to the efficiency and capacity of power delivery equipment and rotating equipment due to increased eddy current losses and non-fundamental frequency torques.
A network element interconnecting two otherwise incompatible networks, network nodes, subnetworks or devices. A gateway is often associated with both a router, which knows where to direct a given packet of data that arrives at the gateway, and a switch, which furnishes the actual path in and out of the gateway for a given packet.
A flywheel is a heavy shaft-mounted rotating disc that absorbs and stores twisting or spinning motion and then releases it as rotational kinetic energy to provide motion to a stationary, or nearly stationary object.
The primary method for keeping a computer secure from intruders. A firewall allows or blocks traffic into and out of a private network or the user’s computer. Firewalls are widely used to give users secure access to the Internet as well as to separate a company’s public Web server from its internal network. Firewalls are also used to keep internal network segments secure; for example, the accounting network might be vulnerable to snooping from within the enterprise.
Interface between the computer room cabling and external cabling coming from a telecommunications carrier or campus cabling.
The number of full cabinets that would exist if all the equipment in the data center were concentrated in full cabinets.
An environmentally controlled centralized space for telecommunications equipment that usually houses Distributor B or Distributor C.
The computer room space occupied by equipment racks or cabinets [TIA 942]
(do not use acronym) – use Entrance Facility to avoid confusion with Equipment Room
The point of emergence for telecommunications cabling through an exterior wall, a floor, or from a conduit.
An entrance to a building for both public and private network service cables (including wireless) including the entrance point of the building and continuing to the entrance room or space. (569)
More commonly ‘static discharge’.
A way of utilizing the local environment around the data center to aid in cooling of the IT load by natural means rather than use more energy. There are two common types of economization, Airside Economization and Waterside Economization; sometimes referred to as LINK. Economization is a great benefit to those who can take advantage of it due to the large energy saving opportunity.
An arrangement of conduits, used to transport electrical, telecommunications cabling or data cabling inside or outside of a data center facility arranged in an array.
The temperature of the air measured using a dry-bulb thermometer such that evaporative cooling has no effect. Typically taken in conjunction with a wet-bulb reading which does include the evaporative cooling effect in order to determine relative humidity.
A liquid-to-air heat exchanger that is a radiator over which air is blown via fans. Typically used as the heat rejection device for water or glycol cooled condensers, may also be used as the heat rejection device for liquid cooled coils in an AHU under proper environmental conditions.
A structure with terminations for connecting the cabling of a facility in such a manner that interconnection or cross-connections may be readily made.
A non-time varying method of delivering power. While slightly more efficient then AC if utilized between the DC portion of the UPS and the power supplies in IT equipment, it has not won wide acceptance in modern data centers.