Refrigeration Principles TERMS (140102a) Flashcards
British Thermal Unit
The Heat Energy Unit of the imperial measurement system and the amount of heat required to raise the temperature of one pound of water one Fahrenheit degree.
Superheating
Increasing the temperature of a vapour above its saturated pressure.
Back Pressure
The low pressure of a refrigeration system. Also called low side pressure and evaporator pressure.
Sil-Fos Silvabrite Solder
Melting Point: 430*F
Flow: 430*F
TQSpecific Density
The ratio of a substance’s mass to the density of a given reference substance (usually water) at a given volume.
Head pressure
The high pressure on a normal refrigeration system, also called high side, condenser or discharge pressure.
Low side pressure
The low-pressure side of a refrigeration system. It aid also called LOW SIDE, SUCTION or EVAPORATOR PRESSURE
Adiabatic Compression
The Compression of refrigerant gas without removing or adding heat
Hydrometer
An instrument that measures the specific gravity of a liquid.
Gas
An invisible state in which a substance attempts to fill its surrounding space; also called VAPOUR
Refrigeration System
A combination of interconnected parts forming a closed circuit in which refrigeration is circulated for the purpose of extracting then rejecting heat.
Enthalpy
The heat in 1 POUND (lb) or KILOGRAM (kg) of a substance from a zero base point at -40* (F or C)
Sil-Fos 15
Melting Point: 1190*F
Flow: 1475*
Refrigerant
A liquid that absorbs heat while evaporating and expels heat while condensing, both at useful temperatures.
Laminar Flow
The smooth undisturbed flow of a fluid within a duct or pipe.
TQ Question
1: ) TON of refrigeration
2. ) How many BTU/24hrs in 1 TON of refrigeration?
1.) A measurement of refrigeration capacity based on the melting of one ton of ice in one day. One ton of refrigeration equals
2.) 288,000 BTU/24hrs
Or 12,000 BTU/Hr
Or 200 BTU/min
Melting point
The temperature at which solids melt.
Hydrostatic Pressure
The force applied by a liquid over an area.
Kilopascal
The SI unit of pressure based on the Pascal. The Kilopascal is 1000 pascals.
Symbol: kPa.
Reclaim
Returning recovered refrigerant to design characteristics by a refrigerant manufacturer.
Cleaning
“We don’t reclaim as techs, we recover”
Kelvin
A temperature scale starting at absolute zero, Kelvin Degrees is the same magnitude at Celsius degrees.
Symbol: K
Sublimation
A change of state from solid directly to a vapour without having a liquid state.
Specific Volume
The amount of space required for a unit of mass of a substance
Absolute temperature
System temperature measurement based on either a starting or a zero point where there is no heat or molecular motion theoretically stops.
Adiabatic Process
A change in pressure, volume and temperature of a vapour without a change in that vapour’s heat content
Hygrometer
An instrument that measures the quantity of H20 in a substance.
Saturation pressure
At a given temperature, the pressure at which vapour and liquid can exist in equilibrium.
Recycle
The process of cleaning recovered refrigerant (using a filter) in a posta me recycling unit on a job site or in a shop.
Ozone (o3)
A molecule composed of three oxygen atoms. Ozone filters harmful ultraviolet solar radiation in the ozone layer, but is a pollutant at ground level.
Micron
One millionth of a metre.
Temperature
Average level of molecule motion.
Manometer
A pressure measuring instrument that is based on liquid movement due to applied gas pressure.
Work
The result of applying a force through a distance.
Sil-Fos 5
Melting Point: 1190*F
Flow: 1495*F
Matter
Any form that takes up space and has a mass
Revolutions per minute. (RPM)
The number of times a shaft will completely revolve in one minute.
Symbol: RPM
Refrigerating effect
The act of removing Heat by any means that reduces the temperature of mass.
Saturation
A mixed condition where one substance holds as much of another substance as possible at a given temperature
Density
The Ratio is MASS and VOLUME. The weight per unit volume of substance.
Evaporation
The process of a liquid changing to a Vapour due to an addition of heat energy and a change in Vapour pressure.
Recovery
The removal of refrigerant from mechanical refrigeration or air conditioning systems.
Dry Bulb Temperature
The SENSIBLE temperature of the air determined with a dry thermometer.
Sil-Fos 5
5% Silver
89% Copper
6% Phos
Pressure
Forced applied over an area
Heat
Thermal energy in the form of molecular motion.
Saturated Vapour
In refrigeration, a vapour that contains as much of a liquid of the same substance as it can hold.
High side
The portions of a refrigerating system that are subject to condensing pressure.
Convection
Heat transferred through FLUIDS by the movement of currents. The fluid becomes lighter and is affected by gravity.
Mass
The quality that gives an object shape and gravitational weight.
Saturation Temperature
At a given pressure, the temperature at which vapour and liquid can exist in equilibrium.
Newton
Definition and Symbol
The force accelerating 1kg of mass at a rate of 1m per second squared.
Symbol: N
Specific Volume
The amount of space required for a unit
Subcool
To lower the temperature of a liquid while it remains at its condensing or saturated pressure.
Absolute Pressure
A system of pressure measurement with a starting position in a perfect vacuum.
Absolute is ZERO lbs/square inch.
Saturated Liquid
In refrigeration, a liquid that contains as much of a Vapour of the same substance as it can hold.
Sensible heat change
A change in a mass’ heat quantity caused by a rise or fall in temperature of that mass.
Threshold limit Value (TLV)
The refrigerant concentration in air for a normal eight hour workday and 40 hour workweek to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.
Note: TLV is a registered trademark of the American conference of government industrial Hygienists. (ACGIH)
Radiation
Heat transferred through vacuums.
IDLH
Immediately dangerous to life or health.
Counter Flow
Two fluids flowing near each other in opposite directions.
Low side
The low-pressure side of a refrigeration system. It is also referred to as the SUCTION SIDE
TQ**Specific gravity**
A ratio of a substances density divided by water density at 4C (39F)
Silvabrite Sil-Fos Solder
96% Tin
4% Silver
Suction side
The low pressure of a refrigeration system. Also called low side pressure, back or evaporator pressure.
Joule
Definition and Symbol
The amount of work done by a force of 1 NEWTON (N) over a distance of 1m
Symbol: J
Suction pressure
The low pressure of a refrigeration system. Also called back pressure or evaporator pressure.
Cross Flow
Two fluids flowing near each other at right angles to each other
What change of state is;
- ) Melting
- ) Freezing
- ) Evaporating
- ) Condensing
- ) Sublimating
- ) Solid To Liquid
- ) Liquid to Solid
- ) Liquid to Vapor
- ) Vapour To Liquid
- ) Solid To Vapour
Energy
The ability to perform work
Force
The creator of motion or acceleration
Superheat
Heat added to a vapour at its saturated pressure.
Sil-Fos 15
15% Silver
80% Copper
5% Phos
Kinetic energy
Energy based in motion.
Humidity
The total water content of a specified air sample. Also the % of water air can hold.
Latent Heat
Non-measurable heat gained or lost with no temperature change
Changes state.
Entropy
A measurement of energy transfer where the energy is moved but not used to do work.
Subcooling
The difference between the temperature at which a liquid is formed from vapour and the measured temperature of that liquid if it remains at its condensing or saturated pressure
Static pressure
The pressure exerted by stationary air
Superheat
Heat added to a vapour at its saturated pressure.
