A/C Study guide HVAC TCAT ALREADY
PASSED
heat which causes a change in temperature of a substance is called - =sensible heat
heat which causes a change in state of a material without a change in temperature is called -
=latent heat
heat which is added to a vapor after the change of state occurs is called - =super heat
heat can travel by
A) conduction
B) convection
C)radiation
D)all of the above - =D)all of the above
the movement of heat by way of fluid (or air) is called
A) conduction
B) convection
C)radiation
D)all of the above - =B)convection
the movement of heat by direct contact is called
A) conduction
B) convection
C)radiation
D)all of the above - =A)conduction
,the standard unit for measuring the quantity of heat in a substance is - =the British Thermal Unit
(BTU)
a refrigerant gives up heat when - =it condenses
it is desirable for refrigerant in the suction line to be slightly superheated in order to - =insure
liquid refrigerant does not enter the compressor
the state of the refrigerant in the suction line should be - =low pressure/low temperature vapor
the state of the refrigerant entering the condenser is - =high pressure/highly superheated vapor
the evaporator - =Transfers heat from the refrigerated space to the refrigerant
which of the following is NOT a thermodynamic property of refrigerants - =flammability
the sequential order of steps in the vapor- compression process are - =compression,
condensation, expansion, vaporization
if a 30 pound cylinder of reclaimed R-12 refrigerant has been stored over night at 70 Degrees
Fahrenheit, the pressure in the cylinder should be approximately - =70.2
pressure lower than atmospheric are measured in
A)inches of mercury ("hg")
B)microns
C)psig
D)either "A" or "B" - =D)either "A" or "B"
zero psia (pounds per square inch absolute) is
A)the same as atmospheric pressure
, B)approximately 14.7 psig at sea-level
C)a pressure which cannot be further reduced
D)both "A" and "B" - =C)a pressure which cannot be further reduced
zero psig (pounds per square inch gauge) is
A)the same as atmospheric pressure
B)approximately 14.7 psig at sea-level
C)a pressure which cannot be further reduced
D)both "A" and "B" - =D)both "A" and "B"
the temperature at which moisture will start to condense from the air is called - =dew point
temperature
a compound pressure gauge measures - =pressure and vacuum
a mechanical shaft seal is necessary on a - =open drive compressor
liquid slugging is - =liquid refrigerant in the compressor clearance space
the clearance space in a reciprocating compressor - =has an effect on compressor capacity
which of the following will cause a change in compressor capacity?
A)suction pressure
B)discharge pressure
C)refrigerant vapor density
D)all of the above - =D)all of the above
the main function of the condenser is to - =remove heat from the refrigerant
PASSED
heat which causes a change in temperature of a substance is called - =sensible heat
heat which causes a change in state of a material without a change in temperature is called -
=latent heat
heat which is added to a vapor after the change of state occurs is called - =super heat
heat can travel by
A) conduction
B) convection
C)radiation
D)all of the above - =D)all of the above
the movement of heat by way of fluid (or air) is called
A) conduction
B) convection
C)radiation
D)all of the above - =B)convection
the movement of heat by direct contact is called
A) conduction
B) convection
C)radiation
D)all of the above - =A)conduction
,the standard unit for measuring the quantity of heat in a substance is - =the British Thermal Unit
(BTU)
a refrigerant gives up heat when - =it condenses
it is desirable for refrigerant in the suction line to be slightly superheated in order to - =insure
liquid refrigerant does not enter the compressor
the state of the refrigerant in the suction line should be - =low pressure/low temperature vapor
the state of the refrigerant entering the condenser is - =high pressure/highly superheated vapor
the evaporator - =Transfers heat from the refrigerated space to the refrigerant
which of the following is NOT a thermodynamic property of refrigerants - =flammability
the sequential order of steps in the vapor- compression process are - =compression,
condensation, expansion, vaporization
if a 30 pound cylinder of reclaimed R-12 refrigerant has been stored over night at 70 Degrees
Fahrenheit, the pressure in the cylinder should be approximately - =70.2
pressure lower than atmospheric are measured in
A)inches of mercury ("hg")
B)microns
C)psig
D)either "A" or "B" - =D)either "A" or "B"
zero psia (pounds per square inch absolute) is
A)the same as atmospheric pressure
, B)approximately 14.7 psig at sea-level
C)a pressure which cannot be further reduced
D)both "A" and "B" - =C)a pressure which cannot be further reduced
zero psig (pounds per square inch gauge) is
A)the same as atmospheric pressure
B)approximately 14.7 psig at sea-level
C)a pressure which cannot be further reduced
D)both "A" and "B" - =D)both "A" and "B"
the temperature at which moisture will start to condense from the air is called - =dew point
temperature
a compound pressure gauge measures - =pressure and vacuum
a mechanical shaft seal is necessary on a - =open drive compressor
liquid slugging is - =liquid refrigerant in the compressor clearance space
the clearance space in a reciprocating compressor - =has an effect on compressor capacity
which of the following will cause a change in compressor capacity?
A)suction pressure
B)discharge pressure
C)refrigerant vapor density
D)all of the above - =D)all of the above
the main function of the condenser is to - =remove heat from the refrigerant
