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Glossary: E

EPA
See Environmental Protection Agency.

Eccentric
Circle or disk mounted off center on a shaft.

Economizer
A mechanism that removes flash gas form the evaporator.

Eddy currents
Induced currents flowing in a core.

EER
See Energy Efficiency Ratio.

Effective area
Actual flow area of an air inlet or outlet. Gross area minus area of vanes or grille bars.

Effective latent heat
The amount of heat absorbed from the cabinet and evaporator.

Effectiveness (absorption systems)
Method of evaluating absorption cooling systems, in which the cooling effect is divided by the work equivalent to the heat supplied to the absorber.

Effective temperature
Overall effect of air temperature, humidity, and air movement on human comfort.

Efficiency
Output of a device, system, or activity, divided by the input necessary to crate the output. In a compressor the efficiency would be the work output, as measured by pressure change, divided by the energy input (usually electrical).

Ejector
A device that uses high fluid velocity, such as a venturi, to create low pressure or vacuum at its throat to draw in fluid from another source.

Electric defrosting
Use of electric resistance heating coils to melt ice and frost off evaporators during defrosting.

Electrical circuits
The electrical wiring that permits flow from the energy source, through the circuit, and back to the energy source.

Electrical resistance
A resistance to (working against) the movement of electrons (flow of electricity).

Electric heating
System in which heat from electrical resistance units is used to heat a building.

Electricity
Electric current or power.

Electric water valve
Solenoid (electrically operated) valve used to turn water flow on and off.

Electrodeposition
Process in which metallic particles are applied to another metal surface through the use of an electric current.

Electrolysis
A chemical change in a substance caused by movement of electricity.

Electrolytic condenser-capacitor
Plate or surface capaple of storing small electrical charges.

Electromagnet
Coil of wire wound around a soft iron core. When electric current flows through the wire, the assembly becomes magnetized.

Electromagnetic Energy
Energy that has both electrical and magnetic characteristics.

Electromotive Force (emf) voltage
Electrical force that causes current (free electrons) to flow or move in an electrical circuit. Unit of measure is volts.

Electron
Elementary portion or particle of an atom that carries a negative charge.

Electronic Control Diagnostics
Trouble codes that may be referenced on an automatic climate control system to diagnose problems.

Electronic leak Detector
Electronic instrument that measures electronic flow across a gas gap. Electronic flow changes indicate presence of refrigerant gas molecules.

Electronic Relay
Electronic switch, such as a triac, that controls a power consuming device.

Electronics
Field of science dealing with electron devices and their uses.

Electronic Sight Glass
Device that sends an audible signal when the system is low on refrigerant.

Electrostatic Air Filter
A device that gives dust particles an electric charge. This causes particles to be attracted to a plate so they can be removed from air.

Embrittlement
To become easily broken.

End Bell
End structure of a plate of an electric motor, which usually holds the motor bearings.

Endothermal
Chemical reaction in which heat is absorbed.

End Play
Slight movement of shaft along its center line.

Energized
Having current flow.

Energy
Actual or the potential ability to perform work.

Energy Audit
The process of accurately determining the current energy consumption for a given area.

Energy Efficiency Ratio (EER)
The ratio of the rated cooling capacity divided by the amount of electrical power used.

Energy Management Cooling System
Controllers used in a system which optimize total energy usage in a building or residence.

Energy Utilization Index (EUI)
A number used to compare energy usage for different areas. It is calculated by dividing the energy consumption by the square footage of the conditioned space.

Enthalpy
total amount of heat in one pound of substance calculated from an accepted temperature base. Temperature of 32F (0C) is accepted base for water vapor calculation. For refrigerant calculations, accepted base is –40F (-40C).

Entropy
Engineering calculations used to determine heat available. Measured in Btu per pound degree change for a substance.

Environment
The surrounding conditions.

Environmental Protection Agency (EPA)
A governmental agency, empowered by the government to protect the environment.

Enzyme
Complex organic substance, originating from living cells, which speed up chemical changes in foods. Cooling slows enzyme action.

Epoxy
Synthetic plastic adhesive.

Equalizer
A device that is used to balance pressure in a system or balance the level of liquids between two containers.

Equivalent Length
The length of piping plus pressure losses due to bends, elbows, fixtures etc.

Ethane (R-170)
A Refrigerant sometimes added to other refrigerants to improve oil circulation.

EUI
See energy utilization Index.

Eutectic
The unique mixture of two substances providing the lowest possible melting temperature.

Eutectic Points
The freezing temperature of eutectic solutions.

Evacuation
Removal of air (gas) and moisture from a refrigeration or an air-conditioning system.

Evaporation
term applied to changing of a liquid to a gas. Heat is absorbed during the process.

Evaporative Condenser
A device that uses an open spray or spill water to cool a condenser. Evaporation of some of the water cools the condenser water and reduces water consumption.

Evaporative Cooling
A cooling method practical in hot and dry climates in which hot air is blown over hot water. As some water evaporates, the remaining water is cooled, and then used to cool air.

Evaporator
Part of a refrigerating mechanism in which the refrigerant vaporizes and absorbs heat.

Evaporator, Dry
Evaporator in which the refrigerant is in the droplet form.

Evaporator, Flooded
Evaporator containing liquid refrigerant at all times.

Evaporator Fan
Fan that increases the airflow over heat exchange surface of the evaporators.

Excelsior
Fine curled wood shavings.

Exfilteration
Flow of air from the building to the outdoors.

Exhaust Valve
A movable port that provides an outlet for the cylinder gasses in a compressor or engine.

Exothermic
Chemical reaction in which heat is released.

Expansion Joint
Device in piping designed to allow movement of the pipe caused by thermal expansion and contraction.

Expansion Tank
A tank used to allow water to expand and contract with temperature changes.

Expansion Valve
Device in refrigerating system that reduces the pressure from the high side to the low side.

Expandable Refrigerant System
A system that discards the refrigerant after it has evaporated.

External Drive
Term used to indicate a compressor driven directly from the shaft or by using an external motor. Compressor and the motor are serviceable separately.

External Equalizer
Tube connected to the low-pressure side of a thermostatic expansion valve diaphragm and tot he exit end of the evaporator.

Extrinsic Semiconductor
An intrinsic semiconductor with impurities added; very sensitive to electrical forces.

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