Data Center Glossary Terms Flashcards
2N
A redundancy model that ensures that every component has a backup such that the data center has no single point of failure.
ACAE
Air Conditioning Airflow Efficiency, the amount of heat removed per standard cubic foot of airflow per minute.
AHU
Air Handling Unit.
ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers is an international technical society organized to advance the arts and sciences of air management.
BACnet
A data communication protocol for building automation and control networks.
CAC
Cold Aisle Containment system that directs cooled air from air conditioning equipment to the inlet side of racks in a highly efficient manner.
CFM
Cubic Feet per Minute, a unit of flow rate, commonly used to specify airflow.
Heat Exchanger
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.
HAC
Hot Aisle Containment, system that directs heated air from the outlet side of racks to air conditioning equipment return ducts in a highly efficient manner.
Harmonic Distortion
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.
HDG
Hot Dipped Galvanized.
Hot Aisle
An aisle where rack backs face into the aisle. Heated exhaust air from the equipment in the racks enters this aisle and is then directed to the CRAC return vents.
HPDC
High-Performance Data Center, a data center with above average kW loading, typically greater than 10kW/rack.
Hot Spot
An area, typically related to a rack or set of racks, where ambient air temperature is above acceptable levels. Typically caused by poor airflow management (insufficient cool air supply or an excess of re-circulation).
HVAC
Heating, Ventilation and Air Conditioning system, the set of components used to condition interior air including heating and cooling equipment as well as ducting and related airflow devices.
N+1
Need plus one, a redundancy concept where capacity is configured to include used capacity plus one additional device to enable continued operations with the failure of one system in the configuration.
PDU
Power Distribution Unit, this typically refers to one of two pieces of equipment in the power delivery chain. One is the combination transformer/breaker panel that is often used between a UPS supplying voltage higher than that used by the IT equipment and the cabinets. The other is the smaller “power strip” like device that is used inside the rack to distribute power to the IT equipment.
PF
Power Factor represents the portion of the apparent power that is real power. The source of power factor is non-resistive components (inductors and capacitors) in the load on an AC power system. These components draw current that is 90 degrees out of phase with the voltage across them resulting in zero real power being delivered. While the power delivery system must carry this current (as well as all the current which does result in real power being delivered), it does no useful work. Power companies often charge a penalty for loads which have a power factor that is significantly far away from 1.0 since the size of the equipment that must be in place is dependent upon the total current delivered, but normal billing is based on real power delivered.
Pole
A row of power receptacles with power supplied from a PDU.
Pole Position
A power receptacle on a pole.
Primary Loop
Refers to the water loop which cools the condenser side of a chiller. This loop is cooled by dry coolers or cooling towers.
PU
Packaged Unit, an air handler that is a complete device shipped ready for use rather than a custom device that is assembled on-site from components.
PUE
Power Usage Effectiveness, a metric defined by the Green Grid, which is a measure of data center efficiency calculated by dividing the total data center energy consumption by the energy consumption of the IT computing equipment. This measure is the inverse of DCiE.
Rack
Device for holding IT equipment, also called a cabinet.
STS
Static Transfer Switch, 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.
Supply Air
The cooled airflow emitted from air conditioning equipment.
S+S
System plus system.
CADE
Corporate Average Data Center Efficiency.
BCM
Branch Circuit Monitoring
CapEx
Capital Expense
CR
Computer Room
DC
Data Center
DR
Disaster Recovery
RMF
Raised Metal Floor
RPO
Recovery Point Objective
RPP
Remote Power Panel
RU
Rack Unit
VPN
Virtual Private Network
WUE
Water Usage Effectiveness
UPS
Uninterruptible Power Supply
BMS
Building Management
Systems
