HVAC Excellence Study Guide with All Correct & 100%
Verified Answers| Already Graded A+ (Just Released)
Heat which causes a change in temperature of a substance is called ✔Correct Answer-Sensible
Heat
Heat added to a substance without a rise in temperature is called ✔Correct Answer-Latent Heat
Heat added to refrigerant in a vapor state after the evaporation process is called ✔Correct
Answer-Superheat
A scroll compressor moved refrigerant by means of ✔Correct Answer-Involute spirals
The movement of heat by way of fluid is called ✔Correct Answer-Convection
The movement of heat through a solid object is called ✔Correct Answer-Conduction
The standard unit for measuring the quantity of heat in a substance ✔Correct Answer-British
Thermal Unit
A refrigerant gives up heat when it ✔Correct Answer-Condenses
Why must refrigerant in the suction line be slightly warmer than the saturation temperature?
✔Correct Answer-Prevent liquid slugging of compressor
It is desirable for refrigerant in the suction line to be slightly superheated in order to ✔Correct
Answer-Insure liquid refrigerant does not enter the compressor
A mechanical shaft seal is necessary on ✔Correct Answer-Semi-hermetic compressor
Liquid slugging is ✔Correct Answer-Liquid refrigerant in the compressor clearance space
The clearance space in a reciprocating compressor ✔Correct Answer-Varies depending on
compressor speed
Which of the following types of air conditioning compressors is most energy efficient ✔Correct
Answer-Centrifugal
Which of the following represent the right order for the functions of a condenser? ✔Correct
Answer-De-superheat, condenses, sub-cools
Refrigerant R-134a vapor enters the compressor at 124 psig, 100°f. It leaves as a liquid from the
condenser sub-cooled 20°f, and the pressure will approximately ✔Correct Answer-124 psig
There are 3 basic types of condensers, the air cooled, the water cooled, and the _______ cooled
✔Correct Answer-Evaporative
, 10 lbs. of refrigerant passing through a water cooled condenser will lose 20 BTU's of heat per lb. If 10
lbs. of water passes through the condenser with an entering temperature of 80°f. The temperature of
the water leaving the condenser is ✔Correct Answer-100°f
The heat removed from the refrigerant by the condenser is ✔Correct Answer-Both sensible and
latent heat
An energy recovery ventilator is ✔Correct Answer-An air to air heat exchanger to recover heat
Which of the following can NOT be used as a low ambient temperature control? ✔Correct
Answer-Crankcase regulating valves
The state of refrigeration in the suction line should be ✔Correct Answer-Low pressure/ low
temperature vapor
The state of refrigerant entering the condenser is ✔Correct Answer-High pressure/ highly
superheated vapor
The evaporator ✔Correct Answer-Transfers heat from the refrigerated space to the refrigerant
Which of the following is not a thermodynamic property of refrigerant ✔Correct Answer-
Flammability
The sequential order of steps in the vapor-compression process are ✔Correct Answer-
Compression, condensation, expansion, vaporization
If a 30 pound container of R-410A refrigerant has been stored over night at 70°F, the pressure in the
cylinder should be approximately ✔Correct Answer-201 psig
Fan airflow pressures are usually measured in ✔Correct Answer-Inches of water column (WC)
Zero psig is ✔Correct Answer-The same as atmospheric pressure
The temperature at which moisture will start to condense from the air is ✔Correct Answer-Dew
point temperature
A compound pressure gauge measures ✔Correct Answer-Pressure and vacuum
When testing the efficiency of an air cooled condenser, the refrigerant condensing temperature
should be no more than ______ higher than the entering air temperature ✔Correct Answer-30°f
When testing the efficiency of a water cooled condenser, the refrigerant condensing temperature
should be approximately _______ higher than the entering air temperature ✔Correct Answer-
10°f
The first function a condenser must perform is to _______ the refrigerant before condensing can
occur ✔Correct Answer-Superheat
A thermostatic expansion valve is designed to maintain ✔Correct Answer-Constant evaporator
superheat
Verified Answers| Already Graded A+ (Just Released)
Heat which causes a change in temperature of a substance is called ✔Correct Answer-Sensible
Heat
Heat added to a substance without a rise in temperature is called ✔Correct Answer-Latent Heat
Heat added to refrigerant in a vapor state after the evaporation process is called ✔Correct
Answer-Superheat
A scroll compressor moved refrigerant by means of ✔Correct Answer-Involute spirals
The movement of heat by way of fluid is called ✔Correct Answer-Convection
The movement of heat through a solid object is called ✔Correct Answer-Conduction
The standard unit for measuring the quantity of heat in a substance ✔Correct Answer-British
Thermal Unit
A refrigerant gives up heat when it ✔Correct Answer-Condenses
Why must refrigerant in the suction line be slightly warmer than the saturation temperature?
✔Correct Answer-Prevent liquid slugging of compressor
It is desirable for refrigerant in the suction line to be slightly superheated in order to ✔Correct
Answer-Insure liquid refrigerant does not enter the compressor
A mechanical shaft seal is necessary on ✔Correct Answer-Semi-hermetic compressor
Liquid slugging is ✔Correct Answer-Liquid refrigerant in the compressor clearance space
The clearance space in a reciprocating compressor ✔Correct Answer-Varies depending on
compressor speed
Which of the following types of air conditioning compressors is most energy efficient ✔Correct
Answer-Centrifugal
Which of the following represent the right order for the functions of a condenser? ✔Correct
Answer-De-superheat, condenses, sub-cools
Refrigerant R-134a vapor enters the compressor at 124 psig, 100°f. It leaves as a liquid from the
condenser sub-cooled 20°f, and the pressure will approximately ✔Correct Answer-124 psig
There are 3 basic types of condensers, the air cooled, the water cooled, and the _______ cooled
✔Correct Answer-Evaporative
, 10 lbs. of refrigerant passing through a water cooled condenser will lose 20 BTU's of heat per lb. If 10
lbs. of water passes through the condenser with an entering temperature of 80°f. The temperature of
the water leaving the condenser is ✔Correct Answer-100°f
The heat removed from the refrigerant by the condenser is ✔Correct Answer-Both sensible and
latent heat
An energy recovery ventilator is ✔Correct Answer-An air to air heat exchanger to recover heat
Which of the following can NOT be used as a low ambient temperature control? ✔Correct
Answer-Crankcase regulating valves
The state of refrigeration in the suction line should be ✔Correct Answer-Low pressure/ low
temperature vapor
The state of refrigerant entering the condenser is ✔Correct Answer-High pressure/ highly
superheated vapor
The evaporator ✔Correct Answer-Transfers heat from the refrigerated space to the refrigerant
Which of the following is not a thermodynamic property of refrigerant ✔Correct Answer-
Flammability
The sequential order of steps in the vapor-compression process are ✔Correct Answer-
Compression, condensation, expansion, vaporization
If a 30 pound container of R-410A refrigerant has been stored over night at 70°F, the pressure in the
cylinder should be approximately ✔Correct Answer-201 psig
Fan airflow pressures are usually measured in ✔Correct Answer-Inches of water column (WC)
Zero psig is ✔Correct Answer-The same as atmospheric pressure
The temperature at which moisture will start to condense from the air is ✔Correct Answer-Dew
point temperature
A compound pressure gauge measures ✔Correct Answer-Pressure and vacuum
When testing the efficiency of an air cooled condenser, the refrigerant condensing temperature
should be no more than ______ higher than the entering air temperature ✔Correct Answer-30°f
When testing the efficiency of a water cooled condenser, the refrigerant condensing temperature
should be approximately _______ higher than the entering air temperature ✔Correct Answer-
10°f
The first function a condenser must perform is to _______ the refrigerant before condensing can
occur ✔Correct Answer-Superheat
A thermostatic expansion valve is designed to maintain ✔Correct Answer-Constant evaporator
superheat
