Power Engineering - 4B9 Practice Questions With Complete
Solutions
The amount of heat absorbed by evaporating water is:
a. 2256 kJ/kg
b. 335 kJ/kg
c. 99.63 kJ/kg
d. 2675.5 kJ/kg
e. 417.46 kJ/kg
a. 2256 kJ/kg
Which of the following statements about evaporator face and
bypass dampers is true?
a. When the face damper is closed the quantity of air passing
over the evaporator coils is at a maximum
b. The dampers decrease the resistance to the passage of air
c. Multispeed blowers cannot be used in combination with
evaporator dampers
d. Actuators are required to provide damper movement
e. Depending on the damper position the quantity of air passing
through the duct varies widely
d. Actuators are required to provide damper movement
When city water is used for cooling, the flow is often controlled
with a _____ valve.
,a. Solenoid
b. Stop
c. Pneumatic
d. Expansion
e. Globe
e. Globe
The refrigerant flow device that was invented to overcome the
problem of liquid slugging of the compressor is the:
a. Manual expansion valve
b. Automatic expansion valve
c. Capillary tube
d. Low pressure float
e. Thermostatic expansion valve
e. Thermostatic expansion valve
Shell and tube condensers can be cleaned mechanically if they
have:
a. Stainless steel tubes
b. Built-in rappers
c. Straight tubes
d. Coiled tubes
e. Built-in sonic cleaners
c. Straight tubes
Which of the following statements about capacity control is
false?
,a. An evaporator may be equipped with a face damper
b. Multi speed blowers and dampers are often used in
combination for the evaporator operation
c. A sectional evaporator is divided into two or more sections
d. The capacity of an evaporator may be controlled by using
either sectional evaporators or evaporator dampers
e. The capacity of the evaporator is designed to be twice the
average maximum sustained load
e. The capacity of the evaporator is designed to be twice the
average maximum sustained load
It is not true that:
a. Finned tube evaporators may be used in the large air
conditioning systems
b. In flooded chiller and during the high load some liquid
refrigerant may leave the evaporator
c. Plate surface evaporator may be used in the refrigerators and
freezers
d. Finned tube evaporator are the only type evaporator that can
be applied as the direct expansion evaporator
e. The dry type evaporator may contain some small amount of
liquid refrigerant in any given time
d. Finned tube evaporator are the only type evaporator that can
be applied as the direct expansion evaporator
Which of the statements about automatic expansion valves is
false?
, a. The control may be used with multiple cooling coils
connected to the same compressor.
b. The valve maintains constant pressure in the evaporator
during compressor operation regardless of the load.
c. The spring force is counter acted by the evaporator pressure
acting upward against the diaphragm that closes the valve.
d. A spring exerting a downward force on the diaphragm tends
to open the valve.
e. When the compressor stops the valve automatically shuts off
a. The control may be used with multiple cooling coils
connected to the same compressor.
Based on operation the two basic types of evaporators are the
dry and _____ evaporator.
a. Flooded
b. Plate surface
c. Direct expansion
d. Bare tube
e. Finned tube
a. Flooded
Temperature actuated controls with a mechanical effect are
operated by which of the following:
1. Bimetallic element
2. Expansion of fluid
3. Vapor pressure
4. Electrical resistance
Solutions
The amount of heat absorbed by evaporating water is:
a. 2256 kJ/kg
b. 335 kJ/kg
c. 99.63 kJ/kg
d. 2675.5 kJ/kg
e. 417.46 kJ/kg
a. 2256 kJ/kg
Which of the following statements about evaporator face and
bypass dampers is true?
a. When the face damper is closed the quantity of air passing
over the evaporator coils is at a maximum
b. The dampers decrease the resistance to the passage of air
c. Multispeed blowers cannot be used in combination with
evaporator dampers
d. Actuators are required to provide damper movement
e. Depending on the damper position the quantity of air passing
through the duct varies widely
d. Actuators are required to provide damper movement
When city water is used for cooling, the flow is often controlled
with a _____ valve.
,a. Solenoid
b. Stop
c. Pneumatic
d. Expansion
e. Globe
e. Globe
The refrigerant flow device that was invented to overcome the
problem of liquid slugging of the compressor is the:
a. Manual expansion valve
b. Automatic expansion valve
c. Capillary tube
d. Low pressure float
e. Thermostatic expansion valve
e. Thermostatic expansion valve
Shell and tube condensers can be cleaned mechanically if they
have:
a. Stainless steel tubes
b. Built-in rappers
c. Straight tubes
d. Coiled tubes
e. Built-in sonic cleaners
c. Straight tubes
Which of the following statements about capacity control is
false?
,a. An evaporator may be equipped with a face damper
b. Multi speed blowers and dampers are often used in
combination for the evaporator operation
c. A sectional evaporator is divided into two or more sections
d. The capacity of an evaporator may be controlled by using
either sectional evaporators or evaporator dampers
e. The capacity of the evaporator is designed to be twice the
average maximum sustained load
e. The capacity of the evaporator is designed to be twice the
average maximum sustained load
It is not true that:
a. Finned tube evaporators may be used in the large air
conditioning systems
b. In flooded chiller and during the high load some liquid
refrigerant may leave the evaporator
c. Plate surface evaporator may be used in the refrigerators and
freezers
d. Finned tube evaporator are the only type evaporator that can
be applied as the direct expansion evaporator
e. The dry type evaporator may contain some small amount of
liquid refrigerant in any given time
d. Finned tube evaporator are the only type evaporator that can
be applied as the direct expansion evaporator
Which of the statements about automatic expansion valves is
false?
, a. The control may be used with multiple cooling coils
connected to the same compressor.
b. The valve maintains constant pressure in the evaporator
during compressor operation regardless of the load.
c. The spring force is counter acted by the evaporator pressure
acting upward against the diaphragm that closes the valve.
d. A spring exerting a downward force on the diaphragm tends
to open the valve.
e. When the compressor stops the valve automatically shuts off
a. The control may be used with multiple cooling coils
connected to the same compressor.
Based on operation the two basic types of evaporators are the
dry and _____ evaporator.
a. Flooded
b. Plate surface
c. Direct expansion
d. Bare tube
e. Finned tube
a. Flooded
Temperature actuated controls with a mechanical effect are
operated by which of the following:
1. Bimetallic element
2. Expansion of fluid
3. Vapor pressure
4. Electrical resistance
