HVAC Glossary & Terms
This glossary was created to assist you in understanding the many air conditioning/cooling/HVAC business words and abbreviations used throughout our website and articles. To navigate to the appropriate section, use the alphabetical buttons below.
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A:
Absolute pressure
Atmospheric pressure + gauge pressure. The pressure of having no matter inside a space, or a perfect vacuum, is known as absolute pressure.
ACCA
ACCA is a non-profit organization with over 60,000 individuals and 4,000 firms in the enclosed environmental and energy services industry as members. www.acca.org is their website address.
Accumulator
A liquid refrigerant storage tank collects liquid refrigerant from the evaporator and prevents it from returning to the compressor.
AC fans
Air movement is provided in heating, cooling, and ventilation systems by fans of various sorts driven by an AC (alternating current) motor.
ACIS
Airedale Controls Integrated Systems (ACIS) is a building energy management system (BEMS) that controls and optimizes a variety of building services across many platforms and protocols. See also BEMS.
Acoustical
Has to do with sound, sound science, or an ability to hear.
ACRIB
Air Conditioning and Refrigeration Industry Board (ACRIB). The official website of ACRIB is www.acrib.org.uk.
AFUE
AFUE stands for Annual Fuel Utilization Efficiency. It uses to know the efficiency of the furnace.
Adapter
The adapter is used to supply AC-DC power for electronic devices.
Adiabatic cooling
The method of lowering heat by changing air pressure produced by volume expansion is known as adiabatic cooling.
AGA
The American Gas Association, Inc. delivers natural gas in the United States.
AHRI
The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) is a trade group that represents HVACR and water heating firms. www.ahrinet.org is their website.
Air conditioner
A device, method, or mechanism that regulates temperature, humidity, and air quality in a specific area.
Air-cooled system
Air is used as the transfer medium to reject heat from the refrigerant in the condenser in this air conditioning system. The air-cooled condenser is usually positioned outside and rejects waste heat.
Air diffuser
The purpose of an air distribution outlet or grille is to guide and develop balanced airstreams.
Air Filters
Air filters protect HVAC equipment from dust, dirt, and other contaminants.
Airflow Volume
The amount of air circulated in space is measured in cubic feet per minute.
Air handling unit
A central unit that includes a fan, heating and cooling elements, filter racks or chambers, dampers, humidifiers, and other central equipment for proper ventilation and extraction. Also, see our pamphlet on Air Handling Units.
Alarm
Alarms contain sensors to detect the presence of smoke. When the alarm detects the smoke, they create a sound to alert.
Alternating Current (AC)
The polarity of a current is constantly reversing, causing the directional flow in a circuit to reverse at regular intervals.
Ambient
Temperature and pressure in normal atmospheric circumstances.
Application
Area or region where an air conditioner, cooling system, or unit will be installed.
ASHRAE
ASHRAE stands for the American Society of Heating, Refrigerating, and Air-Conditioning Engineers. The official website of ASHRAE is www.ashrae.org.
Assembly
Gathering HVAC parts in the unit to perform any function.
Azeotrope/azeotropic mixture
A product created by combining two or three chemicals with identical vapor and liquid constituents. Distillation cannot separate an azeotrope into its constituent elements.
Azeotropicpoint
When a liquid combination boils, it generates a vapor with the same chemical composition as the liquid.
B:
BEMS
Building Energy Management System is a computer-based control system that monitors and regulates the mechanical and electrical equipment in a building, including ventilation, lighting, power systems, fire systems, and security systems. Designed to improve system performance, lower operational costs, and simplify decision-making. See also ACIS.
Blend
A refrigerant mixture consists of two or more refrigerants combined in a precise ratio and separated by distillation. A temperature slide of up to 10°C or more is possible in regular blends.
Blower Wheel
The purpose of the blower wheel is to transport enormous amounts of air through the duct system. When dirt or grease accumulates on the blower wheel, it slows the wheel's rotation and reduces the quantity of air your blower motor can move around your home.
Blower motor
The blower motor can move around your home. The heating and cooling system component that sends conditioned air from the furnace, heat pump, or air conditioner into the home is the HVAC blower motor.
Brackets
Brackets are used to hold things together, usually at right angles to one another.
BREEAM
Building Research Establishment Environmental Assessment Methodology is the world's oldest and most commonly used technique for evaluating, rating, and certifying building sustainability. www.breeam.org.
Bonnet
When the supply air temperature falls below a pre-defined comfort level (established by the installer), the bonnet control switch delivers a signal to the motor to lower the airflow.
BTU
The amount of heat needed to increase or reduce the temperature of one pound of water by one degree Fahrenheit is measured in British Thermal Units.
Bubble point
Before combustion, the gas or fuel travels through this aperture in the burner.
Burner
A burner is a device that facilitates the combustion of air and gas.
Burner Orifice
The burner orifice passes the gas/ fuel to the combustion chamber.
C:
Capacity
The output of a heating or cooling unit is calculated in BTUs per hour. It is referred to as HVAC capacity.
Capillary tube
A flow restricting the metering device consists of a tiny diameter tube. This works best in a controlled environment.
Carbon Usage Effectiveness (CUE)
The ratio of total carbon dioxide emission from the data center to total IT system energy consumption is known as carbon usage effectiveness (CUE). It's calculated by dividing total energy consumption (in CO2 emissions) by total IT energy consumption.
Cascade system
A system that uses multiple refrigerant circuit loops in series to attain the optimum cooling level.
Cassette unit
Cassette air conditioners are suitable for both business and home use. They fit easily and quietly into any area with a suspended ceiling, making them ideal for big open plan areas or irregularly shaped rooms.
Celsius
Under normal atmospheric pressure, the freezing point of water is 0° and the boiling point is 100° on a temperature scale.
Centrifugal compressor
A compressor with a rotating wheel pushes the refrigerant outwards to the wheel's rim and then to the condenser. It uses centrifugal force to compress the gas.
CFC
CFC means high ozone depletion and global warming gasses, such as chlorofluorocarbons. (e.g. R12). Since the year 2000, it has been prohibited.
CFCs
CFCs (chlorofluorocarbons) have long been used as refrigerants. The production and usage of such compounds have been phased out in favor of alternatives that do not deplete the ozone layer, such as hydrofluorocarbons (HFCs).
CFM
The abbreviation CFM stands for cubic feet per minute.
Change of state
A transition between solid, liquid, or gas phases.
Charging system
Coolant, or refrigerant, is added to an HVAC system.
Chilled water system
Water or glycol solutions are used as a secondary cooling system in this sort of air conditioning system. A chiller, which is placed remotely, contains the primary cooling system (refrigerant). The chiller chills the water before piping it to the air conditioner to cool the area.
Chiller
A chiller is a machine that uses a vapor-compression or absorption refrigeration cycle to extract heat from a secondary cooling system (water or glycol solution, etc.). As needed, the secondary cooling medium can be pumped through a heat exchanger to cool air.
CIBSE
CIBSE stands for Chartered Institution of Building Services Engineers. The official website of CIBSE is www.cibse.org.
CITB
CITB is an abbreviation for the Construction Industry Training Board. The official website is www.citb.co.uk.
Cleanroom
A clean room is an area with a low degree of environmental impurities, such as dust, airborne microorganisms, aerosol particles, and chemical vapors employed in manufacturing or scientific research.
Coil
The coil, also known as the evaporator coil, is connected to the furnace's airflow outlet. The coil circulates conditioned refrigerant to cool the structure in the summer and heat it in the winter. Temperature and humidity are removed from warm interior air as it goes through the indoor or evaporator coil, resulting in cooler indoor air. Installing a properly sized and rated evaporator coil is critical for getting the most out of your central air conditioning or heat pump system in terms of performance and comfort.
Cold aisle
Cold aisle is a data center layout plan for server racks and other computing equipment. Server racks are arranged in alternating rows with cold air intakes facing one direction and hot air exhausts facing the other in a cold aisle data center. Cold aisles are rows made up of rack fronts. For more information, see Data Center Aisle Containment.
Comfort air conditioning
Comfortable air conditioning equipment is designed to keep people, livestock, and other animals comfortable, not to safeguard computer-based power equipment or other process operations that require precise environmental control.
Commercial air conditioning
Large structures, such as hotels, hospitals, and other commercial buildings, require air conditioning to provide enough ventilation and air - conditioning.
Commissioning
After installation, a service is required to ensure that the equipment is set up to function correctly, according to specifications, and maximize system efficiency to give the best performance.
Compressor
A vital part of the refrigeration system that raises the refrigerant's pressure (and thus temperature) and circulates it via a closed-loop system.
Condensate
When air is cooled below its dew point, moisture is removed; this is commonly connected with moisture removal during the dehumidification process in air conditioning.
Condenser
A vessel or an air-cooled coil that condenses the refrigerant gas into a high-pressure liquid by removing the super-heat of compression.
Condenser Coil
During the summer months, the external coil takes heat from the refrigerant, allowing the refrigerant to be transformed from vapor to liquid and complete the refrigeration process.
Condenser Fan
A fan helps remove heat from the refrigerant by speeding up the passage of air over the condenser coil.
Condenser Unit
Compressor, motor, and condenser heat exchanger; delivered as a single unit to be matched with a suitable evaporator in a refrigeration/air conditioning system. Condensers and condensing units are also available.
Conduction
Heat is transferred through the movement of electrons or the vibration of molecules when two or more bodies of different temperatures come into contact.
Constant air volume (CAV)
The heating, ventilation, and air-conditioning (HVAC) system Constant Air Volume (CAV) is a type of HVAC system. The supply air flow rate is constant in a simple CAV system, but the supply air temperature is changed to suit the thermal loads of space.
Controls
Heating and cooling control system that regulates the system. The actual state (e.g., temperature) is compared to a target state using a sensing device.
Convection
As two fluid streams move across each other, heat is transferred via changes in density in the fluid or gas.
Cooling tower
As two fluid streams move across each other, heat is transferred via changes in density in the fluid or gas.
CSA
A water-saving device that provides water for cooling condensers.
COP
The refrigerant impact (total capacity) vs compressor effort over a unit of time is measured by the coefficient of performance (COP); the higher the number, the more efficient the system.
CRAC
Computer Room for controlling Air Handling Unit.
CWR
Coolant water returns to the chiller.
CWS
CWS means chilled water supply.
D:
Damper
These sheet metal plates, which are found at the connection locations of ductwork, can be kept open or closed to control the flow of air into a region.
Data Center
A data center is a building that houses computer systems and related components, including telecommunications and storage.
DC
Direct Current is a type of electricity. An electrical current that runs solely in one direction.
Decant
Clean empty cylinders to store refrigerant temporarily for repair.
Degree-Day
Calculated by subtracting 65 degrees Fahrenheit from the average outdoor temperature for a given location. This measurement is used to calculate how much heating and cooling a home or building will require.
Dehumidification
To maintain the proper humidity level in a conditioned room, moisture is removed from the air.
Density
A substance's weight per unit volume.
Dew Point
The temperature and pressure at which refrigerant gas transitions from vapor to liquid. Also used to describe the saturation point of the air.
Diffuser
A grille has vanes that spread the discharge air in a precise pattern or direction across an air supply duct.
Direct Expansion Systems (DX)
Direct expansion system used in HVAC cooling systems. Refrigerant converts heat air to cool air and refrigerant is controlled by a direct expansion valve.
DOE
Energy Department. www.energy.gov is their official website.
Downflow Furnace
Air is discharged downward, immediately beneath a raised floor, and is typically encountered in computer rooms and modern office buildings.
Drain Pan
A condensate pan is also included. The drain pan gathers the condensate as the refrigerant vapor liquefies and directs it to the drain line.
Drop-in
A gas that can be installed into a refrigeration system intended for a different gas without requiring major system modifications. In many situations, R422D can be used as a direct substitute for R22.
Dry Bulb Temperature
The temperature was measured without taking humidity into account.
Ductwork
Supply air, return air, and exhaust air is all delivered and removed through ducts in heating, ventilation, and air conditioning (HVAC).
E:
EC fan
Brushless DC motors with built-in electronics that convert AC to DC without the necessity of a separate DC source are used in Electronically Commutated (EC) fans. Through Precision
Economizer
In Air Conditioning (PAC) units, EC fans provide a more efficient (up to 30%) means of airflow, as well as variable speed control via an output signal from the unit controller.
EER
A mechanical device used to reduce energy usage is known as an economizer. Economizers improve efficiency by recycling energy generated within a system or reducing temperature differences in the surroundings.
Electronic Expansion Valve (EEV)
The Energy Efficiency Ratio (EER) is a metric that measures a system's efficiency under a set of rating criteria. The cooling capacity in kW is divided by the power input in kW to get this ratio.
Energy Technology List (ETL) / ECA Scheme
The Enhanced Capital Allowance (ECA) Scheme is an important component of the government's climate change strategy. It gives firms more tax breaks for equipment purchases that meet published energy-saving criteria.
Enthalpy
Total internal energy + total heat and heat content Pv/J are the thermodynamic properties of a substance. Also known as total heat and heat content.
Entropy
The rate of heat absorption into an item.
Energy Reuse Effectiveness (ERE)
Is the proportion of total energy consumed to the energy emitted from the data center and reused elsewhere? It can be discovered by dividing the quantity of energy reused by the total amount of energy consumed by the data center.
Energy Reuse Factor (ERF)
Is the proportion of data center energy reused elsewhere in the facility to the total energy brought into the data-center control volume (including IT, cooling, power, lighting, etc.)
EPA
The US Environmental Protection Agency (USEPA) is a governmental agency in the United States that was established to protect human health and the environment by creating and implementing regulations based on laws passed by Congress. www.epa.gov is their website address.
ESEER
The Seasonal Energy Efficiency Ratio is a measure of equipment energy efficiency, similar to the EER, but tailored to the European market. Rather than employing a single condition (EER), the SEER considers four seasonal conditions for changing load performance of chillers, etc., and assigns the equipment a relevant rating number.
Evaporator coil
Indoors, an evaporator coil is commonly found in a split system, an air handler, or a duct system. As it absorbs heat from the air that flows over it, refrigerant evaporates inside the coil.
Evaporating temperature
Within an evaporator, the temperature at which a refrigerant vaporizes.
Expansion valve
A mechanism that controls how much refrigerant flows into the evaporator from the liquid line. A thermostatically controlled valve, a capillary tube, or a fixed orifice device are all examples of fixed orifice devices.
F:
F-Gas
Fluorinated gasses ('F-gasses') are a type of man-made gas that is utilized in air conditioning and refrigeration systems. Hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and Sulfur hexafluoride are the three types (SF6).
F-Gas regulation
These were created as a result of the necessity of removing ozone-depleting gasses.
Fahrenheit
In 2007, an EU rule was enacted into European Law. Fluorine-based refrigerants are affected. Engineers must keep records, detect leaks, and have a certain skill level. See the F Gas Compliance section.
Fan
At normal atmospheric pressure, water freezes at 32 degrees and boils at 212 degrees on a temperature scale.
Fan coil unit
A fan coil unit (FCU) is a chilled water device that includes a heating and/or cooling coil, fan, valve or valves, and a local controller. It's a component of a larger HVAC system found in homes, businesses, and factories.
Filter
Multiple filters may be used in a central heating and cooling system. The air filter is an essential component of the system intake ducting because it keeps impurities out of the equipment and must be cleaned or replaced regularly. The refrigeration system also has a filter, sometimes known as a drier, that functions as a strainer to remove dirt and unwanted particles from the system.
Filter-Drier
A desiccant-containing device in a refrigeration unit that is used to remove water.
Flame sensor
The flame sensor detects flame in the furnace.
Flue
A vent that exhausts a furnace's combustion waste.
Flue collar
A flue collar connects with vent piping to the chimney. It allows the smoke to escape a place.
Fluorocarbon
Fluorine and carbon-based compounds. Fluorocarbons, which include CFCs, HCFCs, HFCs, and HFOs, are the most common refrigerants.
Footprint
When an air conditioner is turned on, it takes up a certain amount of space.
Free Cooling
This might be a system that uses fresh air to cool the space or a water-cooled or glycol-cooled system with an extra coil that delivers chilled water cooling when the outside temperature is cold, minimizing or eliminating the need for a compressor running. These systems can provide free cooling for up to 80% of their service life, which is very useful in northern regions.
Furnace
The primary gas-fired heating component. A device that allows for the burning of fuel and air to produce heat, which is subsequently circulated to the residence using a fan.
Fuse
A thin metal strip that connects two electrical circuit components. This strip acts as a circuit protector, breaking or melting if there is an excess of electrical charge, breaking the circuit.
G:
GAMA
Association of Gas Appliance Manufacturers
Gauge pressure
When a gauge is zeroed at atmospheric pressure (one bar absolute or 14.7 psi), pressures can be read as negative when below atmospheric pressure.
Glide
The boiling temperatures of the various components of a refrigerant blend vary, resulting in a change in the relative components of the blend over a temperature range.
Glycol-Cooled System
A water/glycol solution is used as the condensing medium in this air conditioning system. The glycol-cooled condenser is usually found inside the air conditioner alongside the other refrigeration components. A dry cooler or another suitable source of water/glycol is piped to the device. During the winter, the glycol stops the solution from freezing.
GWP
Global Warming Potential
H:
HCFC
Lower ozone depletion happened because global warming gasses are hydrochlorofluorocarbons (e.g., R22).
Heat capacity
The amount of heat required to raise a mass's temperature by one degree, Kelvin.
Heat exchanger
A heat exchanger is a piece of equipment designed to transfer heat between two physically separated fluids efficiently.
Heat Pump
A heat pump is a mechanical device that receives low-grade heat from a colder place and upgrades and transfers the high-temperature medium formed by mechanical work to heat a space to a comfortable temperature.
Heat transfer
Air to air, air to water, water to water, and ground to water heat pumps are all options.
Hemi-anechoic chamber
A room designed to entirely absorb sound or electromagnetic signal reflections. Hemi-anechoic chambers contain a solid floor that serves as a work area for heavy goods, such as huge air conditioning units that are used to measure sound levels.
HFC
R134a is a hydrofluorocarbon refrigerant gas with 0% ODP, It is a significant global warming potential.
HFO
Hydrofluoroolefin is a 4th generation refrigerant gas with 0% ODP. It is low global warming.
High-Performance Computing(HPC)
To address significant issues in research, engineering, or business, high-performance computing refers to the process of aggregating computing capacity in a way that gives much higher performance than a normal desktop computer or workstation.
Hot aisle
A hot aisle is a data center layout plan for server racks and other computing equipment. In a hot aisle data center, server racks are arranged in alternating rows, with cold air intakes facing one direction and hot air exhausts facing the other. Hot aisles are the rows into which heated exhausts are directed.
Humidification
The process of introducing moisture into a space's air.
Humidistat
The humidifier is turned on and off by this device, which detects humidity.
Humidity
Water vapor causes dampness in the air.
HVAC
HVAC stands for heating, ventilation, and air conditioning.
Hydrocarbon refrigerant (HC)
A refrigerant made up entirely of carbon and hydrogen. Propane (R290), isobutane (R600a), and the CARE range are some of the most common examples. Low GWP and zero ODP.
I:
Ignition
Increasing the temperature of a substance to the point where it will ignite.
Ignitor electrode
The ignitor electrode is a component of the ignition systems that are used for the gas combustion process.
Interconnection Agreement
A connection between power systems allows them to draw on reserve capacity from each other when needed.
Internet Service Provider (ISP)
An Internet service provider (ISP) is a company that provides access to, use of, and participation on the Internet.
Inverter compressor
The compressor motor speed is controlled by an inverter drive, which modulates capacity as demand changes.
K:
Kilowatt (kW)
An air conditioning system's cooling capacity, heating capacity, and power consumption are expressed as a flow of energy.
Kyoto Protocol
In Kyoto, Japan, an international accord to combat global warming was reached. This document lays out objectives for lowering greenhouse gas emissions, which are assumed to be the cause of global warming. More HFC usage limits are likely to be based on this approach.
L:
Latent Cooling Capacity
The amount of energy added or taken from the air during the air conditioning process increases or decreases the moisture content of the air. It's measured in kilograms per kilogram of dry air.
Latent Heat
A body or a thermodynamic system releases or absorbs energy during a constant-temperature process that results in a change of state. The latent heat of evaporation, for example, causes a phase shift from liquid to vapor at a given temperature and pressure.
Low-pressure stage
From the expansion device outlet to the compressor suction inlet in a single-stage refrigerant system. It is the part of a multi-stage system when the lowest temperature is obtained.
M:
Make Up Air Unit (MUA)
A supply fan for replacing air that has been drained from a building. MUA can be heated or cooled to ensure that the air entering the building does not have a significant impact on the air conditioning systems, but it is not designed to cool or heat the structure.
Manufacturer Approved System
When replacing a condensing unit, furnace, or air handler, make sure the system is manufacturer-certified and AHRI-matched. Installation of systems that are not compatible is strongly discouraged.
Media
A filter's thin substance captures dirt, dust, mildew, or bacteria.
Microchannel coil
The Microchannel coil model is based on automotive technology. It is made up of parallel flow aluminum tubes manually brazed to increased aluminum fins, resulting in improved heat transmission and a smaller, lighter, corrosion-resistant coil.
Mineral oil
A lubricant having a low affinity for the moisture is often used with HCFC and HFC refrigerants.
N:
N+1
N+1 redundancy is a type of resilience that guarantees system availability even if a component fails. At least one independent backup component (+1) exists for each component (N).
NATE
North American Technician Excellence is the largest non-profit certification organization for HVAC, A/C, and refrigeration technicians in the United States. The HVACR industry governs, owns, operates, develops, and supports NATE, the only technician certification organization. www.natex.org is NATE's official website.
Natural refrigerant
Ammonia (R717), carbon dioxide (R744), and hydrocarbons such as propane (R290) or isobutane (R290) are non-fluorochemical refrigerants (R600a). These goods are found in the natural world. Alternative to fluorochemical refrigerants, with minimal direct GWP and ODP potential.
Near azeotrope
Combining two or more chemicals results in this chemical product. It has virtually identical vapor and liquid constituents. The temperature glide of near azeotropes is less than 2oC.
NEC
National Electric Code/National Energy Council
NEMA
NEMA stands for the National Electrical Manufacturing Association.
Non-condensable gas
A gas that does not condense at the temperature and partial pressure that exists in the condenser, resulting in higher head pressure. When air leaks into a system, this happens frequently, lowering system efficiency and causing long-term reliability difficulties.
O:
ODP
Ozone Depletion Potential is a measure of ozone layer degradation relative to R11=1.
Oil separator
A mechanism that separates the refrigerant from the oil.
Orifice
A hole or aperture.
P:
Packaged unit
A self-contained air handling equipment designed for outdoor use, with all heating and cooling components pre-assembled before installation.
Particulates
Combustion gasses contain tiny liquid or solid particles. The US Environmental Protection Agency regulates the number and size of particles produced by automobiles, power and industrial plants, wood stoves, and other sources.
Plenum
A pressurized container containing a positive-pressure gas (usually air) (pressure higher than surroundings). One of the plenum's functions is to control and equalize pressure for better distribution.
Precision Air Conditioning (PAC)
Precision Air Conditioning systems are largely intended for process cooling, such as data centers or manufacturing equipment, rather than for human comfort. These systems are extremely dependable and often have a high sensible-to-total cooling capacity ratio (COP).
Pressure and strength tests
A thermostat that allows the user to program a pre-set schedule of times and temperatures for enabling or disabling HVAC equipment into the device's memory.
Programmable thermostat
A pound per square inch is a unit of pressure equal to one pound of force applied to one square inch of surface area.
PSI
Absolute pounds per square inch indicates that the pressure is measured against a vacuum rather than the ambient atmospheric pressure. Because atmospheric pressure at sea level is roughly 14.7 psi, any pressure reading taken in air at sea level will be adjusted accordingly.
PSIA
Absolute pounds per square inch indicates that the pressure is measured against a vacuum rather than the ambient atmospheric pressure. Because atmospheric pressure at sea level is roughly 14.7 psi, any pressure reading taken in air at sea level will be adjusted accordingly.
PSIG
The pressure is measured in pounds per square inch and is related to atmospheric pressure.
Psychrometric
The study of atmospheric conditions, particularly air moisture.
Psychrometric Chart
Based on 1kg of air, the psychrometric chart depicts factors relating to the condition of air and its change of state.
PUE
The power use effectiveness (PUE) of a data center is calculated by dividing the total energy consumed by the energy consumed by its IT equipment. PUE numbers can be anything between 1.0 and infinite. A PUE score of 1.0 represents 100 percent efficiency, with all energy being consumed solely by IT equipment.
R:
R-number
When a refrigerant is accredited by ASHRAE, it is given an official number.
R1234ze (HFO Refrigerant)
R1234ze is a Hydro Fluoro Olefin (HFO)-based refrigerant with a GWP lower than one, better than CO2, according to the International Panel on Climate Change (IPCC). It's thought to be a replacement for R134a. Also, TurboChill R1234ze, a low-GWP refrigerant, keeps John Lewis cool.
R134a (HFC Refrigerant)
R134a (Tetrafluoroethane) is a haloalkane refrigerant with no risk for ozone depletion that was developed to replace R12. Automobile air conditioning, refrigerators, and chillers are among their most common applications.
R22(HCFC Refrigerant)
R22 is a refrigerant gas used in most air conditioning systems older than ten years. R22 is a hydrochlorofluorocarbon that, if released into the atmosphere, has ozone-depleting potential (ODP).
R407C (HFC Refrigerant)
R407C is a zeotropic hydro-fluorocarbon refrigerant that combines difluoromethane (R32) for heat capacity, pentafluoroethane (R125) for flammability reduction, and tetrafluoroethane (R134a) for pressure reduction. Pentafluoroethane and tetrafluoroethane are served by difluoromethane. R407C was created as an alternative to the ozone-depleting R22.
R410A (HFC Refrigerant)
R410A is a third-generation hydro-fluorocarbon refrigerant that was created to replace ozone-depleting chemicals. It's a zeotropic but near-azeotropic mixture of difluoromethane (CH2F2 also known as R32) and pentafluoroethane (CHF2CF3, also known as R125) that's utilized in air conditioning.
Rack
A computer rack (also known as a rack) is a metal frame that holds a variety of hardware components such as servers, hard disc drives, modems, and other electronic devices.
Radiant floor
A form of radiant heating system in which heated fluids such as air or water are pumped through channels or tubes in the building floor.
Radiation
The use of electromagnetic waves to transport heat across matter or space.
RCI
The Rack Cooling Index (RCI) is a metric that calculates the percentage of racks in a data center where the air input temperature is within ASHRAE's recommended or acceptable range.
Reciprocating Compressor
A type of compressor that uses a piston to compress refrigerant in cooling systems.
Reclaim
Filtering, drying, distillation, and sometimes chemical treatment of the recovered refrigerant to reprocess and upgrade it. Laboratory testing of the reprocessed chemical will be required to ensure that it meets a certain quality standard, usually that of a new refrigerant. Processing is usually done "off-site" at a re-processing or refrigerant production facility.
Recovery
Taking wasted gas from a refrigerator system and packaging it. Avoids environmental release, which is both environmentally irresponsible and illegal in many countries. A refrigeration contractor is normally hired to complete this task. This might happen during routine maintenance or when permanently removing a refrigerant owing to equipment retirement or retrofitting to different gas.
Recycle
Before reuse, increase the quality of recovered refrigerant. This is to remove moisture, acidity, and particulate matter from refrigerant through oil separation, distillation, and single or repeated runs through filter driers. On-site or off-site recycling is possible.
Refrigerant
The heat transfer fluid in a refrigeration unit. At low temperatures and pressures, the refrigerant absorbs the heat and transmits it at high temperatures and pressures. Many materials can be used as refrigerants, including fluorocarbon compounds, natural refrigerants like ammonia, CO2, hydrocarbons, and other components, including water and air.
Refrigerant charge
In a closed system, the proportion of refrigerant is in kilograms.
Refrigeration Cycle
The vapor compression refrigeration loop uses a closed system to circulate a consistent volume of refrigerant gas. The refrigerant collects waste heat from the conditioned area in the evaporator and denies it through the condenser by altering pressure and temperature within the system.
Relative humidity
The ratio of the partial pressure of water vapor in an air-water combination to the saturated vapor pressure of water at a given temperature is known as relative humidity. The discrepancy between relative humidity and percentage saturation (ratio of moisture content) in current Northern European circumstances is less than 1%. They should be treated differently in high-temperature places because the difference can be as much as 10%.
Remote Electronic Expansion Valve
An EEV can be put in specially built evaporators with a remote control panel. Electronic Expansion Valves are another option.
Retrofit
To improve the performance of the refrigerant system by replacing the refrigerant gas, adding energy-saving components, and so on.
S:
Screw compressor
A Compressor utilizes the action of two synchronized screws to pressurize the refrigerant vapor.
Scroll compressor
A compressor with two compliant scrolls, one fixed and the other oscillating, that compresses the refrigerant as it travels between them. The scroll compressor, which is widely used in air conditioning systems, can be fixed or variable capacity, with digital unloading or inverter control.
SEER
The Seasonal Energy Efficiency Ratio, defined by the Air Conditioning, Heating, and Refrigeration Institute as the cooling output during a normal cooling season divided by the total electric energy input during the same period, is frequently used to rate the efficiency of air conditioners.
Self-contained system
The quantity of thermal energy extracted from the air without affecting its moisture content.
Sensible Cooling Capacity
The quantity of thermal energy extracted from the air without affecting its moisture content.
Sensible Heat
A temperature change is caused by the addition or subtraction of heat.
Sensible Heat Ratio (SHR)
The sensible heat to total heat ratio.
Sensor
A gadget that responds to changes in the environment.
Server
A server is a computer system that responds to requests over a network to provide or assist in the provision of network services.
Single-Speed
A single-speed motor works at maximum speed until the temperature preset is reached, then shuts off. They're often louder at startup, utilize more energy, and put more strain on mechanical parts than other motor types.
split systems
The outdoor (condensing) unit and the indoor unit are the two primary components of a split air conditioning system. A split system can refer to any size of device, but it usually refers to smaller equipment, such as air-to-air heat pumps.
Subcooling
The process of removing heat from a liquid to a temperature below its saturation temperature at a certain pressure. This is most commonly seen in the condenser heat exchanger.
Superheating
Superheating is the process of heating a vapor to a temperature higher than the saturation temperature at that pressure, for example, steam at >100oC. This is most common in the evaporator.
T:
Thermostat
A wall-mounted device that monitors and adjusts an HVAC system's output.
The thermostatic expansion valve (TEV)
A precise control device that regulates the rate at which liquid refrigerant flows into the evaporator to control evaporator superheat.
Thyristor
Thyristors are semiconductor devices that can switch electric currents and are frequently used to control the output of electric heaters.
Ton
12,000 BTUs per hour equals one ton.
Turning Vane
Turning vanes are devices used within mechanical ductwork to smoothly move air inside the duct when the direction changes, minimizing resistance and turbulence.
Two-Speed
Two-speed motors are the foundation for a high-efficiency air conditioner. They start in low gear and strive to meet the cooling load for the home, shifting to high gear if necessary. It cycles back to low before shutting off once it reaches the appropriate temperature. It has fewer speeds than single-speed motors, which decreases start-up noise, increases energy efficiency, and puts less stress on mechanical elements.
U:
Up-flow Furnace
A furnace that draws air in from the bottom and pushes it out the top.
Up-flow unit
An air conditioning system with a top-mounted discharge plenum or an overhead duct system that discharges air into the conditioned space.
UPS
When the input power source, usually mains power, fails, an uninterruptible power supply (UPS) supplies emergency power to the load.
V:
Vacuum
A space with a pressure that is much lower than atmospheric pressure.
Vacuum test
A test that draws a vacuum on a refrigeration system to assess its gas tightness before charging it with refrigerant.
Vapor
A variable-speed motor, which is ideal for high-efficiency air conditioners, works similarly to a two-speed motor but with many speeds. It provides smoother cycling and more precise performance control than single- or two-speed motors, as well as the quietest operating, maximum energy economy, and least mechanical stress.
Vapor barrier/seal
A vapor seal is vital for preventing moisture infiltration into or moving out of a critical environment, such as a data processing center or another room with sensitive electronic instruments. A vapor seal is a barrier that stops air, moisture, and contaminants from flowing into the crucial area through tiny cracks or pores in the walls, floor, and ceiling. It's also widely used on pipe insulation to keep moisture out, which can cause the insulation to deteriorate or freeze in cold weather.
Variable-Speed
A variable-speed motor, which is ideal for high-efficiency air conditioners, works similarly to a two-speed motor but with many speeds. It provides smoother cycling and more precise performance control than single- or two-speed motors, as well as the quietest operating, maximum energy economy, and least mechanical stress.
The process of moving air into and out of interior space, either mechanically induced (driven) or naturally.
Ventilation
The process of moving air into and out of interior space, either mechanically induced (driven) or naturally.
Volt
Is the electrical potential and electromotive force's derived unit.
Voltage
Electrical current is pushed along wires and cables by this force.
W:
Water-Cooled system
Water is used as a condensing medium in refrigerant-based air conditioning systems. The water-cooled condenser is usually found within the air conditioner alongside the other refrigeration components. A cooling tower or another suitable supply of water is piped to the unit.
Water Usage Effectiveness (WUE)
Is a Green Grid-developed site-based statistic that evaluates the amount of water utilized on-site for data center operations. This comprises humidification water as well as the water evaporated on-site for energy production or cooling the data center and its support systems.
Watt
In the International Unit System (SI), the watt is a derived measure of power named after Scottish inventor James Watt (1736–1819). The joule per the second unit can be used to describe the rate of energy conversion or transmission in relation to time.
Wet Bulb Temperature
The wet-bulb temperature is the temperature at which a parcel of air would be cooled to saturation (100 percent relative humidity) by the evaporation of water into it, with the parcel supplying the latent heat.
Wet Bulb Thermometer
The relative humidity in the air is measured by a thermometer.
Z:
Zoetrope
Refrigerant blends are made up of two or more chemical compounds that are typically employed separately as refrigerants in various applications. Zeotropic mixes, unlike azeotropes, distillate more easily into their constituent elements.
Zoning
A system that divides a home, office, or facility into different zones to better monitor the temperature and efficiency of a heating and cooling system.
