RETA Industrial Refrigeration Book 2
(2025 Revision) With Correct
Solutions!!
Which of the following factors listed below does not affect heat transfer?
(pg. 1-2)
A) Temperature Difference
B) Surface Area
C) Thermal Conductivity
D) Density CORRECT ANSWERS D) Density
An example of a poor conductor of heat is? (pg. 1-3)
A) Aluminum Tubing
B) Schedule 40 Steel Pipe
C) Wood
D) Water CORRECT ANSWERS C) Wood
Thermal conductivity ('K') is? (pg. 1-3)
A) Exactly the same for any metal
B) The number of BTU's that will pass in 1 hour through a material 1" thick with an area
of 1 sq. ft. if the temperature difference from one side to the other is 1°F
C) A measure of the total energy (heat content) per pound of refrigerant measured in
BTU's
D) A relationship between heat and temperature that is useful in determining discharge
temperatures. It is heat moved into or out of the process, divided by the absolute
temperature in BTU's/pound/R CORRECT ANSWERS B) The number of BTU's that will
pass in 1 hour through a material 1" thick with an area of 1 sq. ft. if the temperature
difference from one side to the other is 1°F
Which is NOT a common source of fouling of a heat exchange surface?
(pg. 1-7)
A) Water
B) Oil
C) Frost
D) Dirt CORRECT ANSWERS A) Water
Which statement is true? (pg. 1-3)
A) The higher the 'k' factor, the greater the thermal conductivity
B) The lower the 'k' factor, the greater the thermal conductivity
C) The higher the 'k' factor, the lower the thermal conductivity
D) The 'k' factor is not associated with thermal conductivity CORRECT ANSWERS A)
The higher the 'k' factor, the greater the thermal conductivity
,Optimum 'U' factor for the given material that the heat exchanger is made of results
when? (pg. 1-7/8)
A) There is no impeding substance such as ice, dirt, or oil on the surfaces of the heat
exchanger tubes
B) Maximum airflow across the evaporator is achieved
C) The system is operating with the design recirculation low
D) The system is maintaining temperature CORRECT ANSWERS A) There is no
impeding substance such as ice, dirt, or oil on the surfaces of the heat exchanger tubes
When air flow is decreased across a heat exchange surface, cooling capacity is? (pg. 1-
10)
A) Reduced
B) Increased
C) Not changed because area is not changed
D) Not changed because evaporator temperature is not changed CORRECT
ANSWERS A) Reduced
Centrifugal fans have an advantage over propeller fans in that they ______________
than prop fans? (pg. 1-12)
A) Require less physical space
B) Consume more hp per CFM of air moved
C) Are quieter
D) Have fewer components to maintain CORRECT ANSWERS C) Are quieter
The operating engineer? (pg. 1-7)
A) Cannot change the 'k' factor of the metal but has some control of the overall 'U' factor
for the evaporator as a unit
B) Can increase 'k' factor by increasing the air velocity over the evaporator and has
some control of the overall 'U' factor for the evaporator as a unit
C) Should allow frost to collect on the evaporator increase 'k' factor
D) Can increase 'k' factor by starting another compressor CORRECT ANSWERS A)
Cannot change the 'k' factor of the metal but has some control of the overall 'U' factor
for the evaporator as a unit
The limiting factor of an evaporator's capacity that the operator cannot control is? (pg. 1-
7)
A) Suction Temperature
B) Suction Pressure
C) Evaporator Size
D) Refrigerant Liquid Feed Flow CORRECT ANSWERS C) Evaporator Size
The best way to keep an evaporator from being affected by oil build-up is to? (pg. 1-8)
A) Operate the system at the correct evaporator temperature
B) Periodically remove oil from the oil collection points
C) Set hot gas defrost cycle for a minimum of 30 minutes
,D) Increase air flow across the evaporators CORRECT ANSWERS B) Periodically
remove oil from the oil collection points
The effectiveness of a heat transfer surface depends on several factors. One factor the
operator has control over is? (pg. 1-8)
A) Evaporator surface area
B) Material the evaporator is made of
C) Type of fans used
D) Cleanliness of the evaporator CORRECT ANSWERS D) Cleanliness of the
evaporator
One advantage of using axial type fans is? (pg. 1-12)
A) Quieter operation
B) They require less motor horsepower per CFM
C) They can move air further across the space to be cooled
D) They can work against a higher static pressure CORRECT ANSWERS B) They
require less motor horsepower per CFM
Which of the following is NOT a result of scale build-up on a condenser coil? (pg. 1-13)
A) Reduced heat transfer
B) Increased operating cost
C) Increased 'U' value
D) Increased condensing temperatures CORRECT ANSWERS C) Increased 'U' value
If 'R' value is doubled, what will happen to the heat transfer rate (assuming the
temperature difference and the area do not change)? (pg. 1-13)
A) The rate of heat that is transferred will be double
B) The rate of heat that is transferred will be cut in half
C) The rate of heat that is transferred does not change
D) The conductance is doubled so that heat transfer rate is increased CORRECT
ANSWERS B) The rate of heat that is transferred will be cut in half
What happens to the theoretical capacity of an evaporator in a 0°F freezer if the
ammonia evaporating pressure is dropped from 8.96 PSIG to 6.11 PSIG? (pg.
A) The capacity of the evaporator is reduced by 50%
B) The capacity of the evaporator is doubled
C) The capacity of the evaporator is not changed
D) The capacity of the evaporator is increased by 50% CORRECT ANSWERS C) The
capacity of the evaporator is not changed
Damaged insulation on the suction line in an ammonia refrigeration system will? (pg. 1-
14)
A) Not change the efficiency of the system because suction pressure will not change
B) Cause efficiency loss and potential damage to the suction line
C) Look bad but will not cause any major problems
, D) Cause an efficiency loss but will not cause any other problems CORRECT
ANSWERS B) Cause efficiency loss and potential damage to the suction line
Enthalpy is? (pg. 2-2)
A) A measure of total energy (heat content) per pound of refrigerant measured in BTU's
B) The net heat absorbing capacity of the refrigerant after the point of expansion
C) The amount of cooling effect that can be obtained from a refrigeration system
D) Heat that cannot be measured through a change in temperature CORRECT
ANSWERS A) A measure of total energy (heat content) per pound of refrigerant
measured in BTU's
The enthalpy diagram? (pg. 2-6)
A) Illustrates the changes of condition and heat content of a pound of refrigerant at
different points of the refrigeration cycle
B) Illustrates the total heat transfer capacity of the system from evaporators through
condensers in tons of refrigeration
C) Utilizes two scales, pressure and tons of refrigeration
D) Does not take into account the effect of flash gas CORRECT ANSWERS A)
Illustrates the changes of condition and heat content of a pound of refrigerant at
different points of the refrigeration cycle
The enthalpy diagram has three regions of refrigerant condition which are? (pg. 2-10)
A) Solid, Liquid and Gas
B) Subcooled Liquid, SAT Liquid and Vapor, and Superheated Vapor
C) Hot, Medium, and Cold
D) Flash Gas, Subcooled Liquid, Subcooled Liquid and Flash Gas CORRECT
ANSWERS B) Subcooled Liquid, SAT Liquid and Vapor, and Superheated Vapor
The pressure scale on an enthalpy diagram typically used in the U.S. is expressed in?
(pg. 2-8)
A) Kilopascals
B) PSIG
C) PSIA
D) Newtons CORRECT ANSWERS C) PSIA
In a refrigeration system (at normal refrigeration pressures), how does the heat content
of a pound of saturated vapor compare to the heat content of a pound of saturated
liquid? (pg. 2-10)
A) The heat quantity in a pound of saturated vapor is greater than the heat quantity in a
pound of saturated liquid at the same pressure
B) The heat quantity in a pound of saturated vapor is less than the heat quantity in a
pound of saturated liquid at the same pressure
C) The heat quantity in a pound of saturated vapor is equal to the heat quantity in a
pound of saturated liquid at the same pressure
(2025 Revision) With Correct
Solutions!!
Which of the following factors listed below does not affect heat transfer?
(pg. 1-2)
A) Temperature Difference
B) Surface Area
C) Thermal Conductivity
D) Density CORRECT ANSWERS D) Density
An example of a poor conductor of heat is? (pg. 1-3)
A) Aluminum Tubing
B) Schedule 40 Steel Pipe
C) Wood
D) Water CORRECT ANSWERS C) Wood
Thermal conductivity ('K') is? (pg. 1-3)
A) Exactly the same for any metal
B) The number of BTU's that will pass in 1 hour through a material 1" thick with an area
of 1 sq. ft. if the temperature difference from one side to the other is 1°F
C) A measure of the total energy (heat content) per pound of refrigerant measured in
BTU's
D) A relationship between heat and temperature that is useful in determining discharge
temperatures. It is heat moved into or out of the process, divided by the absolute
temperature in BTU's/pound/R CORRECT ANSWERS B) The number of BTU's that will
pass in 1 hour through a material 1" thick with an area of 1 sq. ft. if the temperature
difference from one side to the other is 1°F
Which is NOT a common source of fouling of a heat exchange surface?
(pg. 1-7)
A) Water
B) Oil
C) Frost
D) Dirt CORRECT ANSWERS A) Water
Which statement is true? (pg. 1-3)
A) The higher the 'k' factor, the greater the thermal conductivity
B) The lower the 'k' factor, the greater the thermal conductivity
C) The higher the 'k' factor, the lower the thermal conductivity
D) The 'k' factor is not associated with thermal conductivity CORRECT ANSWERS A)
The higher the 'k' factor, the greater the thermal conductivity
,Optimum 'U' factor for the given material that the heat exchanger is made of results
when? (pg. 1-7/8)
A) There is no impeding substance such as ice, dirt, or oil on the surfaces of the heat
exchanger tubes
B) Maximum airflow across the evaporator is achieved
C) The system is operating with the design recirculation low
D) The system is maintaining temperature CORRECT ANSWERS A) There is no
impeding substance such as ice, dirt, or oil on the surfaces of the heat exchanger tubes
When air flow is decreased across a heat exchange surface, cooling capacity is? (pg. 1-
10)
A) Reduced
B) Increased
C) Not changed because area is not changed
D) Not changed because evaporator temperature is not changed CORRECT
ANSWERS A) Reduced
Centrifugal fans have an advantage over propeller fans in that they ______________
than prop fans? (pg. 1-12)
A) Require less physical space
B) Consume more hp per CFM of air moved
C) Are quieter
D) Have fewer components to maintain CORRECT ANSWERS C) Are quieter
The operating engineer? (pg. 1-7)
A) Cannot change the 'k' factor of the metal but has some control of the overall 'U' factor
for the evaporator as a unit
B) Can increase 'k' factor by increasing the air velocity over the evaporator and has
some control of the overall 'U' factor for the evaporator as a unit
C) Should allow frost to collect on the evaporator increase 'k' factor
D) Can increase 'k' factor by starting another compressor CORRECT ANSWERS A)
Cannot change the 'k' factor of the metal but has some control of the overall 'U' factor
for the evaporator as a unit
The limiting factor of an evaporator's capacity that the operator cannot control is? (pg. 1-
7)
A) Suction Temperature
B) Suction Pressure
C) Evaporator Size
D) Refrigerant Liquid Feed Flow CORRECT ANSWERS C) Evaporator Size
The best way to keep an evaporator from being affected by oil build-up is to? (pg. 1-8)
A) Operate the system at the correct evaporator temperature
B) Periodically remove oil from the oil collection points
C) Set hot gas defrost cycle for a minimum of 30 minutes
,D) Increase air flow across the evaporators CORRECT ANSWERS B) Periodically
remove oil from the oil collection points
The effectiveness of a heat transfer surface depends on several factors. One factor the
operator has control over is? (pg. 1-8)
A) Evaporator surface area
B) Material the evaporator is made of
C) Type of fans used
D) Cleanliness of the evaporator CORRECT ANSWERS D) Cleanliness of the
evaporator
One advantage of using axial type fans is? (pg. 1-12)
A) Quieter operation
B) They require less motor horsepower per CFM
C) They can move air further across the space to be cooled
D) They can work against a higher static pressure CORRECT ANSWERS B) They
require less motor horsepower per CFM
Which of the following is NOT a result of scale build-up on a condenser coil? (pg. 1-13)
A) Reduced heat transfer
B) Increased operating cost
C) Increased 'U' value
D) Increased condensing temperatures CORRECT ANSWERS C) Increased 'U' value
If 'R' value is doubled, what will happen to the heat transfer rate (assuming the
temperature difference and the area do not change)? (pg. 1-13)
A) The rate of heat that is transferred will be double
B) The rate of heat that is transferred will be cut in half
C) The rate of heat that is transferred does not change
D) The conductance is doubled so that heat transfer rate is increased CORRECT
ANSWERS B) The rate of heat that is transferred will be cut in half
What happens to the theoretical capacity of an evaporator in a 0°F freezer if the
ammonia evaporating pressure is dropped from 8.96 PSIG to 6.11 PSIG? (pg.
A) The capacity of the evaporator is reduced by 50%
B) The capacity of the evaporator is doubled
C) The capacity of the evaporator is not changed
D) The capacity of the evaporator is increased by 50% CORRECT ANSWERS C) The
capacity of the evaporator is not changed
Damaged insulation on the suction line in an ammonia refrigeration system will? (pg. 1-
14)
A) Not change the efficiency of the system because suction pressure will not change
B) Cause efficiency loss and potential damage to the suction line
C) Look bad but will not cause any major problems
, D) Cause an efficiency loss but will not cause any other problems CORRECT
ANSWERS B) Cause efficiency loss and potential damage to the suction line
Enthalpy is? (pg. 2-2)
A) A measure of total energy (heat content) per pound of refrigerant measured in BTU's
B) The net heat absorbing capacity of the refrigerant after the point of expansion
C) The amount of cooling effect that can be obtained from a refrigeration system
D) Heat that cannot be measured through a change in temperature CORRECT
ANSWERS A) A measure of total energy (heat content) per pound of refrigerant
measured in BTU's
The enthalpy diagram? (pg. 2-6)
A) Illustrates the changes of condition and heat content of a pound of refrigerant at
different points of the refrigeration cycle
B) Illustrates the total heat transfer capacity of the system from evaporators through
condensers in tons of refrigeration
C) Utilizes two scales, pressure and tons of refrigeration
D) Does not take into account the effect of flash gas CORRECT ANSWERS A)
Illustrates the changes of condition and heat content of a pound of refrigerant at
different points of the refrigeration cycle
The enthalpy diagram has three regions of refrigerant condition which are? (pg. 2-10)
A) Solid, Liquid and Gas
B) Subcooled Liquid, SAT Liquid and Vapor, and Superheated Vapor
C) Hot, Medium, and Cold
D) Flash Gas, Subcooled Liquid, Subcooled Liquid and Flash Gas CORRECT
ANSWERS B) Subcooled Liquid, SAT Liquid and Vapor, and Superheated Vapor
The pressure scale on an enthalpy diagram typically used in the U.S. is expressed in?
(pg. 2-8)
A) Kilopascals
B) PSIG
C) PSIA
D) Newtons CORRECT ANSWERS C) PSIA
In a refrigeration system (at normal refrigeration pressures), how does the heat content
of a pound of saturated vapor compare to the heat content of a pound of saturated
liquid? (pg. 2-10)
A) The heat quantity in a pound of saturated vapor is greater than the heat quantity in a
pound of saturated liquid at the same pressure
B) The heat quantity in a pound of saturated vapor is less than the heat quantity in a
pound of saturated liquid at the same pressure
C) The heat quantity in a pound of saturated vapor is equal to the heat quantity in a
pound of saturated liquid at the same pressure
