Use cold air to cool an exterior water tower. The chilled water from the tower is then used in the air conditioners inside the data center instead of mechanically-chilled water, reducing energy costs. Water-side economizers often operate during nighttime to take advantage of cooler ambient temperatures. Economizers can save data center operators substantial operating costs. According to GreenerComputing.org, economization has the potential to reduce the annual cost of a data center’s energy consumption by more than 60 percent. Use of cooler external environmental temperatures to preserve hardware is an important component in sustainable green computing practices in general. Unfortunately, economizers are only useful for data centers located in cooler climates.
A sustainability metric defined by The Green Grid, which is a measure of the water used on-site for data center operations including humidification and on-site evaporation for cooling or energy production. WUE is calculated by dividing ‘annual water usage’ by the ‘energy consumption of the IT computing equipment’ The units of WUE are liters/kilowatt-hour (L/kWh).
A unit of apparent power. In AC circuits, the magnitude of the voltage across a circuit times the current through the circuit is the apparent power. Including a representation of the angle between the two waveforms in the form of power factor (see PF) yields the real power.
A unit of electrical potential.
A system that samples the air on a continuing basis and can detect fire at the pre-combustion stage. Pronounced VEZ-DUH.
An enclosed passageway, usually placed between buildings, for the distribution of utility services.
A data center efficiency metric developed by the Uptime Institute synonymous with UCE. (see also CoE).
A device placed in series with the supply of power from the utility which contains energy storage such that the supply of power from the UPS is continuous even when the utility supply is removed. While battery-based energy storage is the most common, flywheel-based energy storage is gaining in popularity due to the reduced maintenance cost. UPS is used to hold the load until either the generator turns on to handle the load or the utility power is restored. Battery based UPS systems have a finite time that they can handle the load, usually less than 10 minutes. Flywheel-based energy storage is usually less than 5 minutes depending on the design.
A data center efficiency metric developed by the Uptime Institute synonymous with UCE. (see also CoE).
A type of resistor with resistance varying according to its temperature.
An enclosed architectural space designed to contain telecommunications equipment, cable terminations, or cross-connect cabling. (TIA 942).
A ceiling that creates an area or space between the ceiling material and the structure above.
The cooled airflow emitted from air conditioning equipment.
The open area underneath a raised computer floor, also called a sub-floor plenum.
A disk storage system which contains multiple disk drives. It is differentiated from a disk enclosure, in that an array has cache memory and advanced functionality, like RAID and virtualization. Attached to SAN for multiple devices to access and store data.
A network of storage disks. In large enterprises, a SAN connects multiple servers to a centralized pool of disk storage. Compared to managing hundreds of servers, each with their own disks, SANs improve system administration. By treating all the company’s storage as a single resource, disk maintenance and routine backups are easier to schedule and control. In some SANs, the disks themselves can copy data to other disks for backup without any processing overhead at the host computers.
A solid state device which transfers the feed of power from one source to another source such as from the incoming utility to a generator.
Refers to either the ceiling or floor that is above a finished ceiling and/or below the raised floor. Often used to measure actual available height of an unfinished data center space and referred to as slab to slab height. Eg. If the raised floor is 3 feet, the finished ceiling is 2 feet and the the finished space is 10 feet; then the slab to slab height is 15 feet.
Chilled airflow returning to cooling units without passing through IT equipment, also referred to as bypass.
