vapour compression system 3

1.

1 point

Why do refrigeration compressors use water jackets?

To remove the heat of compression

To prevent the refrigerant from freezing in the cylinders

To prevent liquid slugging

To ensure the refrigerant gas is completely vaporized

2.

1 point

Calcium chloride is suitable for temperatures down to:

-22 degrees Celsius

-15 degrees Celsius

0 degrees Celsius

-40 degrees Celsius.

-34 degrees Celsius

3.

1 point

One tonne of refrigeration is equal to:

1103 kJ/min.

335000 kJ/min.

335 kJ/min.

233 kJ/min.

one tonne of melted ice.

4.

1 point

An indirect refrigeration system uses

a brine solution

a remote evaporator.

a flooded evaporator.

a separate cold storage room.

5.

1 point

In an atmospheric condenser, the condensing medium is:

Air

Brine

Refrigerant vapor.

Water

Air and/or water.

6.

1 point

The lower a refrigerant's boiling point at atmospheric pressure, the:

More heat it will absorb.

Greater will be its density.

Greater will be its condensing pressure.

More expensive it is.

7.

1 point

In an atmospheric condenser

water circulates between the outside and inside tubes.

water flows through the inner tube.

water trickles over the outside of the tubes.

air is blown through the tubes.

8.

1 point

Which of the following are classified as Group 1 refrigerants?

Ammonia
Carbon dioxide
Water
Freon 12
Sulphur dioxide

1 and 5 are correct

2 and 3 are correct

2 and 4 are correct

1, 2, 3, 4 and 5 are correct

2, 3 and 4 are correct

9.

1 point

Where does the refrigerant change from a liquid to a gas?

At the compressor discharge

In the evaporator

In the receiver

In the condenser

10.

1 point

A refrigerant should

condense at a high pressure.

not stick to surfaces.

absorb a large amount of heat.

evaporate at a high pressure.

condense at a low temperature.

11.

1 point

When the refrigerant passes through the expansion valve it is

a superheated liquid.

a subcooled liquid.

mostly a liquid and part gas.

mostly a gas and part liquid.

12.

1 point

Carbon dioxide is rarely used as a refrigerant that much anymore because it

will support combustion.

has a low latent heat capacity.

has a high condensing pressure.

depletes the ozone layer.

causes suffocation.

13.

1 point

In a refrigeration process, the refrigerant gas is changed to a liquid in the

condenser

receiver

evaporator.

compressor

14.

1 point

The compressor is located

always in line with the expansion valve.

at the point of no pressure change.

in the low side of the system.

in the high side of the system.

at the dividing line between the high and low side.

15.

1 point

The maximum amount of heat removed by an ice box with a 10 kg block of ice is

3350 kJ.

2330 kJ

233 kJ

33500 kJ.

1103 kJ.

16.

1 point

In a standard refrigeration cycle, the temperature in the evaporator is:

-34 degrees Celsius.

-15 degrees Celsius.

20 degrees Celsius.

0 degrees Celsius.

30 degrees Celsius.

17.

1 point

Evaporation coils

are used to circulate refrigerant

are found only in an ammonia system.

are where the heat transfer occurs

are located on the back of a domestic refrigerator

should contain the entire charge of refrigerant.

18.

1 point

In a double pipe condenser, the water flows

through the inner tube.

between tube sections.

over the outer tube

through the space between the tubes.

around the tubes.

19.

1 point

The difference in cooling water inlet and cooling water outlet temperature should be around

22 degrees Celsius.

10 degrees Celsius

5 degrees Celsius.

18 degrees Celsius.

13 degrees Celsius.

20.

1 point

Where does the pipe take the refrigerant off from the receiver?

The end

The side

The bottom

The top