Vapor pressure created in a container by a mixture of gases is equal to sum of individual vapor pressures of the gases contained in mixture.
Device for controlling airflow.
Stirring mechanism in a dispensing freezer.
Act of separating air from a substance.
Unit used for measuring relative loudness of sounds.
Deck (coil deck)
Insulated horizontal partition between refrigerated space and evaporator space.
Refrigerating cycle in which evaporator frost and ice accumulation is melted.
Device, connected into electrical circuit, that shuts unit off long enough to permit ice and frost accumulation on evaporator to melt.
Process of removing frost accumulation from evaporators.
Evaporator operating at such temperatures that ice and frost on surface melts during the Off cycle.
Removal of oil or grease from refrigerator parts with a solution or solvent.
Unit that represents on degree of difference from inside temperature and the average outdoor temperature; often used in estimating fuel requirements for a building.
Device used to remove moisture from air.
Lubricant that has had most of its water content removed (dry oil).
Small tank that serves as liquid refrigerant reservoir and also contains a desiccant to remove moisture. Used on most automobile air conditioning installations.
Device for operating a refrigerating system in such a way as to provide melting of the accumulated ice and frost.
Three-phase electrical transformer that has ends of each of three windings electrically connected to form a triangle.
Instrument that measures the kilowatt-hour usage of a circuit or group of circuits.
Closeness of particles within a given substance. The weight per unit volume.
Device that absorbs or adsorbs various odors, usually by principle of absorption. Activated charcoal is commonly used.
Department of Transportation (DOT)
A governmental unit that regulates the transportation of refrigerants from one location to another.
A bag used to keep water cool in the desert. The fabric is not waterproof, so water leaks through and evaporates, cooling the water inside the bag.
Substance used to collect and hold moisture. A drying agent. Common desiccants are activated alumina and silica gel.
Highest pressure expected during operation. Sometimes calculated as operating pressure plus a safety allowance.
Device used to detect and locate refrigerant leaks.
Condensed atmospheric moisture deposited in small drops on cool surfaces.
Temperature at which vapor (at 100% humidity) begins to condense and deposit as a liquid.
A two-lead alternating current semiconductor that allows current to flow in both directions at a preset voltage.
The process of identifying or determining the nature and circumstances of an existing condition.
Flexible material usually made of thin metal, rubber, or plastic.
Refrigerant commonly known as R-12.
Die casting (dc)
Process of molding low-meltingtemperature metals in accurately shaped metal molds.
Fluid with high electrical resistance.
The difference between cut-in and cut-out temperature or pressure of a control.
Attachments for duct openings that distribute the air in wide flow patterns.
two-element electrontube that will allow more electron flow in one direction in a circuit than in the other direction; tube that serves as a rectifier.
Direct current (dc)
Electron flow that moves continuously in one direction in a circuit.
Direct Digital Control (DDC)
Use of digital computer to perform required automatic control operations in a total energy management system.
Direct expansion evaporator
Evaporator using either an automatic expansion valve (AEV) or a thermostatic expansion valve (TEV) refrigerant control.
A furnace control in which a spark is used to ignite the gas-air mixture. There is no constantly-burning pilot light.
A freezer with built-in dispensing equipment, used for serving ice cream and frozen drinks.
Volume obtained by multiplying the area of the cylinder bore by the length of the piston stroke.
Fluid-reclaiming device used to reclaim used refrigerants. Reclaiming is usually done by vaporizing and then condensing refrigerant.
Systems that help evenly and efficiently transfer the heating or cooling medium to the area where it is needed.
District heating and cooling
Use of a central utility system designed to provide heating and cooling to large residential and industrial areas.
Sealed metal container for the motor compressor of a refrigerating unit.
A heater located around the door opening of a freezer, used to prevent ice buildup from freezing the door closed.
Commercial refrigerator in which a part of space is for refrigerated storage and part is equipped with glass windows for display purposes.
Copper, aluminum, or steel tubing end that has been formed into two-wall thickness, 37 to 45 bell mouth or flare.
Accurately dimensioned pin pressed into one assembly part and slipped into another assembly part to ensure accurate alignment.
A furnace in which return air enters through the top and is pulled down through the heat exchanger. Also called counterflow furnace.
Instrument used to measure air movement by measuring air pressure differences.
Instrument used to indicate or measure chimney draft or combustion gas movement. Draft is measured in units of 1" of water column.
Device that maintains a desired draft in a combustion-heated appliance by automatically controlling the chimney draft to the desired value.
Substance or device used to remove moisture from a refrigeration system.
Pan-shaped panel or trough used to collect condensate from evaporator.
An instrument with a sensitive element to measure ambient air temperature.
Dry bulb temperature
Air temperature as indicated by an ordinary thermometer.
See Electrolytic capacitor.
Dry cell battery
Electrical device used to provide dc electricity, having no liquid in the cells.
Refrigerating substance made of solid carbondioxide, which changes directly form a solid to a gas (sublimates). its subliming temperature is -109F (-78C).
Refrigeration system that has the evaporator liquid refrigerant mainly in the atomized or droplet condition.
A combination of a high-pressure and low-pressure regulator.
Tube or channel through which air is conveyed or moved.
A tool used to remove dirt and debris from ducts.
Device for measuring power output or power input of a mechanism.