Refrigeration Flashcards
Rankine =
Farenheit + 460
Kelvin =
Celsius + 273
Temperature can be thought of as
A description of the level of heat
Water boils at
100 C, 212 F
Water boils at 212 F under which psi
14.696
As the temperature of a material increases, the molecules in the material
travel faster
Celsius to Fahrenheit equation
X times 1.8 + 32
Fahrenheit to Celsius equation
X - 32 / 1.8
The amount of heat required to change the temperature of a substance varies with the substance, which is…
Specific heat
Atmospheric pressure at sea level
29.92” Hg
A bourdon tube is often found in a
Pressure gauge
A solid material exerts pressure or force
Downward only
A liquid material exerts pressure or force
Outward and downward
A vapour material exerts pressure
In all directions
If the temperature remains constant and the volume that a gas occupies increases, the pressure will
Go down
Boyles Law
Volume and pressure relationship
Charles Law
Volume and temperature relationship
Daltons Law
Mixture of gases and pressure relationship
Unit for electrical power
Watts
One watt = How many btu
3.413
What happens to ice in a drink
Melts from heat absorption
Temperature inside of a fridge
35 Degrees F
Refrigeration is
The process of removing heat from a place where it is not wanted to a place where it makes little to no difference
A ton of refrigeration is equal to
288,000 Btu/24-hr
What parts of the refrigeration cycle change the vapour to a liquid and liquid back into a vapour
Condensor and Evaporator
Evaporator is used to
Absorb heat for the product to be cooled
Reciprocating compressors have a
Piston and cylinder
Condenser is used to
Reject heat from the refrigerant
The compressor is used to
Pump refrigerant throughout the system
Which refrigerant has no chlorine in it
R-134A
Oil in a refrigeration system containing an HFC
POE
Refrigerants near azeorope or zeatrope are
HFCs
Term for desirable behaviour of oil and refrigerant is
Miscibility
Best method of leak checking is
Nitrogen 150 Psig
When moisture is present in a refrigeration system, it will react with the refrigerant and oil to form
Acid
Noncondensable gases are
Undesirable in a refrigeration system
To pull a vacuum means
Lower the pressure in a system below atmospheric
A micron gauge is used to measure
Absolute pressures below 1 mm hg
Deep vaccum is how many microns
500-250
Multiple evacuation means
Pull a vacuum multiple times
Connecting line material for most accurate testing is
Copper tube
Refrigerant in vapour form must enter through the
Suction line
When charging a system with vapour refrigerant, the cylinder becomes
Cold
Refrigerant in liquid form enters through the
Liquid line
How is a cylinder placed when charging a system
Upside down
If a system is overcharged, what happens
Increased operating pressures
Fractionation/glide occurs when
Some of a blended refrigerant evaporates or condenses before the rest of the blend
When charging or running a system with 410A, what must be done to prevent liquid from entering the system
Charge as a liquid through the low side with a restriction
Change of state from solid to vapour
Sublimation
Which component can suffer from internal ice accumulation?
Metering device
The oil in a vacuum pump should be changed…
After every use
Maximum pressure for leak testing with nitrogen
150 psig
Air left in a system can lead to
Compressor failure
