AIR 121 Midterm Review
The amount of heat in Btu/lb., that is given off by the system in the discharge line and the condenser is known as ___________.
Total heat of rejection
(True or False) Only liquid refrigerant should enter the meter device.
True
Latent heat of condensation is the amount of heat energy, in Btu/lb. required to change a ____________ into a ___________.
Vapor, liquid
One ton of refrigerant is _________.
12,000 Btu
To change from pig to psi you must add ________ to psig.
14.696
The latent heat of fusion for a water to ice transformation is _____________.
144 Btu/lb.
To change one pound of water at 32°f to 212°f takes _______ Btu's of _________ heat.
180 Btu's, sensible heat
One British thermal unit will raise the temperature ________ lb. of water ______ °F
1lb.,1°F
How many Btu's are there in 8kw of electrical power?
27,304 Btu's
A ton of refrigeration is equal to __________.
288,000 Btu/24 hr
The atmosphere will support a column mercury _________ inches at sea level.
29.92
Atmospheric pressure at sea level under standard conditions is _________ inches of mercury (Hg) or ________ pounds per square inch absolute (psia).
29.92, 14.696
What are the Btu's of 1 Watt?
3.413 Btu's
What are the Btu's of 1 KW?
3413 Btu's
How many watts of electrical power are equal to 1horsepower?
746 watts
To change boiling water at 212°F to vapor takes ________ Btu's of __________ heat
970 Btu's, latent heat
Latent heat causes ________.
A change of state
An increase in sensible heat causes _________.
A higher thermometer reading
Reciprocating compressors have
A piston and cylinder
What is matter?
A substance that takes up space and has weight
High-Temperature refrigeration is produced by ___________.
An air conditioning system
Good ventilation is important when working around refrigeration equipment because modern refrigerants ___________.
Are heavier than air and may displace the oxygen around you
The law that states that the volume of a gas varies inversely with the absolute pressure, provided the temperature remains constant is ________.
Boyle's law
The law that states at a constant pressure, the volume of a gas varies directly as to the absolute temperature, and at a constant volume the pressure of a gas varies directly with the absolute temperature is _________.
Charles' law
The compressor in a refrigeration system __________.
Compresses the refrigerant and pumps the refrigerant throughout the system
The law that states the total pressure of a confined mixture of gases is the sum of the pressure of each of the gases in the mixture is ___________.
Dalton's law
Weight per unit volume of a substance is?
Density
What does refrigerants such as CFC's and HCFC's do when allowed to escape into the atmosphere?
Deplete the stratosphere ozone layer
The density of a substance ____________.
Describes its mass to volume relationship
The amount of heat a substance contains from some starting point is the definition of __________.
Enthalpy
In which direction does heat flow?
From hot to cold
What color is the cylinder R-22?
Green
Specific volume is used to ________.
Indicate the space a weight of gas will occupy
The evaporator in a refrigeration system __________.
Is the component where the refrigerant boils and absorbs heat
Latent heat of vaporization is the amount of heat energy, in Btu/lb. required to change a ____________ into a ____________.
Liquid, vapor
All matter has ______.
Mass
What does the meter device do in refrigeration system?
Meters refrigerant
When a substance is heated, the molecules ___________.
Move faster
When heat transfers by conduction, it ______________.
Moves from molecule to molecule
When heat transfers by convection, it ______________.
Moves from one place to another by air or liquid
When heat transfers by radiation, it _____________.
Moves through space and air and heats solid objects
The quantity of heat expressed in Btu/lb. that the refrigerant absorbs from the refrigerated space to produce useful cooling is known as ____________.
Net refrigeration effect
A near-azeotropic refrigerant blend replacing R-22 in residential and commercial air-conditioning applications is __________.
R-410a
The process of removing heat from a place where it is not wanted and transferring it to a place where it makes little or no difference is known as ___________.
Refrigeration
The condenser _________.
Rejects the heat from the refrigerant
The condenser in a refrigeration system _________.
Rejects the heat from the refrigerant
What color is the cylinder R-410?
Rose
A substance when it contains all of another substance it can hold is known as __________.
Saturation
What are the 3 states in which matter is commonly found?
Solid, Liquid, and Gas
The density of a substance compared to the density of water is?
Specific gravity
The temperature of a liquid when it is cooled below its condensing temperature is known as _______.
Subcooling
Specific heat is the amount of heat necessary to raise the temperature of 1lb. of a _________ 1°F.
Substance
The temperature of a vapor refrigerant above its saturation temperature is known as _________.
Superheat
The level of heat is the definition of ____________
Temperature
according to the pressure/enthalpy chart, as refrigerant flows through the compressor _____________.
The pressure, temperature and heat content of the refrigerant all increase
