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# Crew Evaluation Test online for seamans about Basic Refrigeration Theory

“Seagull CES marine test online about Basic Refrigeration Theory” (Crew Evaluation Test) will help marine specialists in preparation to exams for getting certificate of confidence.

This test contains 22 questions. Mode “Practice” and “Exam” have one difference – in “Exam” mode you can’t ask the computer to show you the right answer.

Choose mode in which you want take CES test:

Start test
0 Kelvin is equal to:
0 °F.
0 °C.
-273,16 °C.
+273,16 °C.
Next question
During automatic operation of a refrigeration system the starting and stopping of the compressor is usually achieved by which of the following?
Low pressure cut out.
Thermostatic switch.
Temperature in the cold room.
Manual on/off switch.
Next question
From the following options select those, which may cause the refrigeration system high pressure cut out to operate and stop the compressor?
Loss of condenser coolant.
Oil carry over.
Ice on the evaporator coils.
Overcharge of refrigerant.
Next question
If a running system regularly requires change of refrigerant, what should be done?
Find the leak and rectify the problem before the system is charged.
Charge the system, modern refrigerants and cheap and do not harm the environment.
Change the system, find the leak and rectify the problem.
Replace the lost refrigerant with nitrogen.
Next question
Put in the correct words. According to the second law of thermodynamics heat can only transfer naturally from a region of high temperature to a region of ____ unless mechanical work is done on the system.
High pressure.
Low temperature.
Equal temperature.
Next question
The closed cycle refrigeration system works on the principle of which of the following?
Rapid expansion and loss of refrigerant.
Rapid expansion and recirculation of the refrigerant.
Vapour compression with loss of refrigerant.
Vapour compression and recirculation of the refrigerant.
Next question
The ideal temperature of a freeze room is:
-26 °C to -30 °C.
-5 °C to -10 °C.
-18 °C to -25 °C.
0 °C to -5 °C.
Next question
The operation of the automatic expansion valve is based on:
Constant evaporator pressure and temperature.
Constant evaporator pressure.
Constant evaporator temperature.
Constant flow of refrigeration medium.
Next question
The operation of the thermostatic expansion valve is based on:
Constant degree of superheat in the vapour at the evaporator.
Constant flow of refrigeration medium.
Constant evaporator pressure.
Constant temperature in the condenser.
Next question
The term “specific enthalpy” of a fluid, measured in kJ/kg, is used to quantity the energy per unit mass due to:
The internal energy.
The sum of the internal energy plus the volume.
The sum of the pressure plus the volume.
The sum of the internal energy plus the product of the pressure and volume.
Next question
To be able to evaporate a medium at -20 °C and to condense the same medium at 30 °C we have to:
Increase the pressure.
Decrease the pressure.
Next question
What are the disadvantages of ammonia as a refrigerant?
It is toxic and inflammable.
It is very expensive.
It can only be used on very large refrigeration systems.
It cannot be used in refrigeration systems with screw compressor.
Next question
What are the main components in a closed refrigeration cycle?
Compressor, condenser, expansion valve and receiver.
Compressor, condenser, expansion valve and evaporator.
Compressor, oil separator, expansion valve and evaporator.
Compressor, condenser and evaporator.
Next question
What is absolute pressure?
It is the same as 100 % vacuum.
Atmospheric pressure plus gauge pressure.
It is equal to atmospheric pressure.
It is the same as gauge pressure.
Next question
What is the disadvantage of the manually operated expansion valve?
It can only be used with modern refrigerants.
It responds to quickly to changes in load.
It cannot be used with modern refrigerants.
It is unresponsive to changes in load.
Next question
What is the main problem with Carbon dioxide as a refrigerant?
Extremely inflammable.
Extremely low working pressure.
Extremely high cost.
Extremely high working pressure.
Next question
What is the saturation temperature?
The temperature at which a fluid boils or condenses, it varies with pressure.
The temperature at which a fluid boils or condenses, it is independent of pressure.
It is the point where the ice starts to melt.
It is the same as critical point for a gas.
Next question
What will be an adequate allowance for oil circulation in a refrigeration system?
One litre of oil for every thirty kilo of refrigerant charge.
One litre of oil for every twenty kilo of refrigerant charge.
One litre of oil for every kilo of refrigerant charge.
One litre of oil for every two kilo of refrigerant charge.
Next question
When the desired cold room temperature is reached in a refrigeration system operating on the direct expansion principle, which of the following shuts off the evaporator for the room?
Thermostatically controlled expansion valve.
Low pressure cut out.
High pressure cut out.
Solenoid valve operated by thermostatic switch.
Next question
Which of the following components are parts of the high-pressure side in a refrigeration system?
Condenser.
Evaporator.
Suction line.
Liquid line.
Next question
Which of the following does the term latent heat describe when referring to a refrigerant?
The temperature.
Heat required to cause evaporation at constant boiling temperature and pressure.
The heat required to superheat the refrigerant gas.
The heat required to raise the liquid temperature to boiling point.
Next question
Which of the following indicates refrigerant undercharge?
Vapour bubbles in the liquid line sight glass.
Compressor running continuously.
Show result
* In some questions may be more, than one right answer.

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Апрель, 05, 2022 359 0
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