Manual for Refrigeration Servicing Technicians - UNEP - Division of ...

Glossary
external forcing, or to persistent anthropogenic changes in the composition of
the atmosphere or in land use. Note that Article 1 of the Framework Convention
on Climate Change (UNFCCC) defines ‘climate change’ as ‘a change of
climate which is attributed directly or indirectly to human activity that alters the
composition of the global atmosphere and which is in addition to natural climate
variability, observed over comparable time periods’. The UNFCCC thus makes a
distinction between ‘climate change’ attributable to human activities altering the
atmospheric composition, and ‘climate variability’ attributable to natural causes.
Coefficient of Performance (COP)
A measure of the energy efficiency of a refrigerating system. The ratio of
useful effect (heat) to the work supplied. The useful effect is the cooling rate in
the case of RAC systems, and it is the heating rate in the case of heat pumps.
The COP is primarily dependant on the working cycle and the temperature
levels (evaporating/ condensing temperature) as well as on the properties of
the refrigerant, system design and size.
Coil
A part of the refrigerating system constructed from bent or straight pipes or
tubes suitably connected and serving as a heat exchanger (evaporator or
condenser).
Competence
The ability to perform satisfactorily the activities within an occupation.
Compressor
A device for mechanically increasing the pressure of a refrigerant vapour.
Condenser
A heat exchanger in which vaporised refrigerant is liquefied by removal of heat
Condensing unit
A combination of one or more compressors, condensers, liquid receivers
(when required) and the regularly furnished accessories.
Containment
The application of service techniques or special equipment designed to
preclude or reduce loss of refrigerant from equipment during installation,
operation, service or disposal of refrigeration and air-conditioning equipment.
Controlled substance
Under the Montreal Protocol, any ozone depleting substance that is subject to
control measures, such as a phase-out requirement.
Destruction
Destruction of ozone depleting substances or their mixtures by approved
destruction plants.
Dew point
Vapour saturation temperature of a refrigerant at the specified pressure; the
temperature at which a vapour refrigerant first begins to condense.
Disposal
Conveying a product to another party, usually for destruction.
Drop-in replacement
The procedure for replacing CFC refrigerants with non-CFC refrigerants in
existing refrigerating, air-conditioning and heat pump plants without doing
any plant modifications. However, drop-in procedures are normally referred to
as retrofitting because plants need minor modifications, such as the change
of lubricant, and the replacement of the expansion device and the desiccant
material.
Emissions
The release of gases or aerosols into the atmosphere over a specified area
and period of time.
Evaporator
A heat exchanger in which liquid refrigerant is vaporized by absorbing heat
from the substance to be cooled.
Expansion device
A device, such as an expansion valve, expansion orifice, turbine or capillary
tube, that is used to control the mass flow of a refrigerant from the highpressure
side to the low-pressure side of a refrigeration system.
Fluorocarbons
Halocarbons containing fluorine atoms, including chlorofluorocarbons,
hydrochlorofluorocarbons, hydrofluorocarbons and perfluorocarbons.
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