Power Engineering - 4th and 3rd Class Refrigeration,
HVAC and Building Environmental Systems Practice
Questions With Complete Solutions
A running vacuum pump connected to a refrigeration tank may:
1. Lower the tank pressure
2. Raise the tank pressure
3. Have no effect on the tank pressure
4. May raise the tank temperature
5. May lower the tank temperature
a. 2, 5
b. 1, 5
c. 2, 4
d. 3, 4
e. 1, 4
b. 1, 5
If a cooled medium had an evaporation temperature of 2C, the
evaporation temperature of the liquid refrigerant should be
approximately:
a. -8C to -3C
b. 2C
c. 6C to 8C
d. 0C
e. 1C
a. -8C to -3C
,Which one does not contribute to the leakage tendency of a
refrigerant gas?
a. Its viscosity
b. Its operating pressure
c. Its molecular mass
d. Its miscibility
e. Its density
d. Its miscibility
Which column of the refrigeration tables lists the absolute
pressure in kPa?
a. Column 4
b. Column 2
c. Column 1
d. Column 5
e. Column 3
b. Column 2
Standard conditions in refrigeration are referred to:
a. 101.3 kPa and 0C
b. 14.7 psi and 0F
c. None of the answers
d. Evaporator temperature at 5F and condenser at 86F
e. Evaporator temperature at 0C and condenser at 15C
d. Evaporator temperature at 5F and condenser at 86F
,Which of the following has the highest boiling point?
a. Water
b. CO2
c. Ammonia
d. Propane
e. Butane
a. Water
Which of the following is not a requirement for an ideal
refrigerant?
a. A non-corrosive action on metals
b. A low boiling point
c. A fairly low condensing pressure
d. A non-poisonous nature
e. Light in weight
e. Light in weight
Which refrigerant does not damage the ozone layer?
a. R-717
b. R-11
c. R-113
d. R-12
e. R-22
a. R-717
, What is the name of the refrigerant that has the following
characteristics? It is nonflammable, odourless, nontoxic, it does
not have a corrosive effect on metal if water is present and at
atmospheric pressure it has a boiling point of -40.6 degrees C.
a. Propane
b. Butane
c. Ammonia
d. Freon-22
e. Sulphur Dioxide
d. Freon-22
Compression ratio is defined as the compressor cylinder _____
pressure divided by the _____ pressure.
a. Gauge suction / gauge discharge
b. Liquid / vapor
c. Absolute discharge / absolute suction
d. Gauge discharge / gauge suction
e. Absolute suction / absolute discharge
c. Absolute discharge / absolute suction
In a refrigeration system:
1- Flashed refrigerant into vapor in an evaporator can be as high
as 30%
2- The flashed refrigerant take part in the actual refrigerating
process
3- The flashed refrigerant amount depends on the temperature
difference between the liquid refrigerant before the control
HVAC and Building Environmental Systems Practice
Questions With Complete Solutions
A running vacuum pump connected to a refrigeration tank may:
1. Lower the tank pressure
2. Raise the tank pressure
3. Have no effect on the tank pressure
4. May raise the tank temperature
5. May lower the tank temperature
a. 2, 5
b. 1, 5
c. 2, 4
d. 3, 4
e. 1, 4
b. 1, 5
If a cooled medium had an evaporation temperature of 2C, the
evaporation temperature of the liquid refrigerant should be
approximately:
a. -8C to -3C
b. 2C
c. 6C to 8C
d. 0C
e. 1C
a. -8C to -3C
,Which one does not contribute to the leakage tendency of a
refrigerant gas?
a. Its viscosity
b. Its operating pressure
c. Its molecular mass
d. Its miscibility
e. Its density
d. Its miscibility
Which column of the refrigeration tables lists the absolute
pressure in kPa?
a. Column 4
b. Column 2
c. Column 1
d. Column 5
e. Column 3
b. Column 2
Standard conditions in refrigeration are referred to:
a. 101.3 kPa and 0C
b. 14.7 psi and 0F
c. None of the answers
d. Evaporator temperature at 5F and condenser at 86F
e. Evaporator temperature at 0C and condenser at 15C
d. Evaporator temperature at 5F and condenser at 86F
,Which of the following has the highest boiling point?
a. Water
b. CO2
c. Ammonia
d. Propane
e. Butane
a. Water
Which of the following is not a requirement for an ideal
refrigerant?
a. A non-corrosive action on metals
b. A low boiling point
c. A fairly low condensing pressure
d. A non-poisonous nature
e. Light in weight
e. Light in weight
Which refrigerant does not damage the ozone layer?
a. R-717
b. R-11
c. R-113
d. R-12
e. R-22
a. R-717
, What is the name of the refrigerant that has the following
characteristics? It is nonflammable, odourless, nontoxic, it does
not have a corrosive effect on metal if water is present and at
atmospheric pressure it has a boiling point of -40.6 degrees C.
a. Propane
b. Butane
c. Ammonia
d. Freon-22
e. Sulphur Dioxide
d. Freon-22
Compression ratio is defined as the compressor cylinder _____
pressure divided by the _____ pressure.
a. Gauge suction / gauge discharge
b. Liquid / vapor
c. Absolute discharge / absolute suction
d. Gauge discharge / gauge suction
e. Absolute suction / absolute discharge
c. Absolute discharge / absolute suction
In a refrigeration system:
1- Flashed refrigerant into vapor in an evaporator can be as high
as 30%
2- The flashed refrigerant take part in the actual refrigerating
process
3- The flashed refrigerant amount depends on the temperature
difference between the liquid refrigerant before the control
