AUXMACH
Refrigerant Knowledge Quiz
Test your understanding of refrigeration systems and refrigerants with our engaging quiz! This quiz covers a wide range of topics, from the properties of refrigerants to the mechanics of refrigeration cycles.
Key Features:
- Multiple-choice questions
- Assess your knowledge and diagnose your understanding
- Ideal for students and professionals in HVAC
Carbon dioxide is?
Odorless
Nonflammable
Colorless
All of the alternatives
The vapor tube connects the evaporator to which of the following?
Metering device
Condenser
Compressor
Crankcase heater
R22 is a type of refrigerant that was completely phased out in 2020 . This type refrigerant belongs to which group of refrigerants?
FCs
HCFCs
HCs
HCs
HFCs
In a refrigerant cycle, the flow of refrigerant is controlled by?
Expansion valve
Condenser
Compressor
Evaporator
If a refrigeration compressor is running continuously without lowering the temperature in the refrigerated space, the trouble may be?
A shortage of refrigerant
Excessive condenser cooling water
Warm food in the refrigerator
A shortage of compressor oil
Which of the following refrigerant that has been used since the 1840's and considered to be a high-class refrigerant as its Ozone Depleting Properties and Global Warming Potential are Zero but was withdrawn from applications as it was considered to be hazardous?
HCs
CO2
FCs
HCFCs
Ammonia
Which evaporator coil is used for storing frozen products and fresh food products?
High temperature coils
Ultra Low temperature coils
Medium temperature coils
Low temperature coils
A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reason/s will be?
Water temperature high
Lack of cooling water
Dirty condenser
All of the alternatives
Which of the following activates if pressure reaches the cut-out setting thereby opening the electrical circuit automatically and closes it again when it reaches cut-in setting?
Low Pressure Control
Compressor Winding Fault switch
High Pressure Control
Overload Protector
Temperature Sensor
The refrigerant after condensation process is cooled below the saturation temperature before throttling. Such process is called?
Super cooling
Sub cooling or under cooling
Normal cooling
All of the alternatives
Which of the following is a measure of the amount of depletion to the Ozone Layer it can cause?
STEL
ODP
Flammability
TWA
GWP
One of the purposes of sub cooling the liquid refrigerant is to
Ensure that only liquid and not the vapour enters the expansion (throttling) valve
Increase cooling effect
Reduce compressor discharge temperature
Reduce compressor overheating
A human body feels comfortable when the heat produced by the metabolism of human body is equal to the
A. Heat dissipated to the surroundings
B. Heat stored in the human body
Sum of (a) and (b)
Difference of (a) and (b)
Which of the following is not a type of compressor?
Rotary
Lateral
Screw
Centrifugal
Reciprocating
Which of the following describes a temperature above the saturation temperature?
Superheat
Saturation
Subcooling
Enthalpy
Which of the following is a part of the refrigerating system that ensures compressor lubricating oil is fed back directly to the crankcase and prevents oil circulating with the refrigerant?
Sight glass
Accumulator
Filter drier
Liquid receiver
Oil separator
Which of the following describes a temperature above the saturation temperature?
By continuous ventilation of the evaporator blower
By temperature sensors
By thermostatic valves
All of the alternatives
Which of the following is a measure of how much heat a refrigerant trap in the atmosphere?
Flammability
STEL
TWA
ODP
GWP
What is absolute pressure? Select the best answer.
Atmospheric pressure plus gauge pressure
It is the same as gauge pressure
It is equal to atmospheric pressure
It is the same as 100% vacuum
Which of the following statements are true in an Accumulator?
I. It acts as a receiver during the heating and defrost cycles when system imbalance or an overcharge from field service could result in excessive liquid refrigerant in the system.
II. It stores the refrigerant until needed and feed it back to the compressor at an acceptable rate.
Both I and II are correct
Neither I and II
The refrigerant rejects heat when it travels through the ___________? Select the best answer.
Expansion Valve
Compressor
Condenser
Evaporator
Which of the following statements may be the cause/causes of short cycling in a refrigerant compressor?
A. Undercharged system / LP cut out faulty or wrong setting / Dirty condenser causing high pressure cut-out.
B. Compressor valve leaking / Low air flow thru the evaporator/ Expansion or solenoid valve malfunction/Low refrigerant
Either a or b
Which of the following procedures use in preventing liquid refrigerant from migrating back to the compressor when the systems is in an off cycle mode.
Pump-down
Abandonment
Recovery
Vacuum
Which of the following produces air movement to the space that is being conditioned?
By thermostatic valves
By temperature sensors
All of the alternatives
By ventilation of the evaporator blower
The formation of frost on cooling coils in a refrigerator
Increases power consumption
Reduces power consumption
Increases heat transfer
Decreases heat transfer
Which of the following is the result of dividing the mass per unit volume?
Enthalpy
Pressure
Density
Condensing temperature in a refrigerator is the temperature______?
Of freezing zone
Of evaporator
At which refrigerant becomes liquid
Of cooling medium
In vapor compression cycle, the condition of refrigerant is high pressure saturated liquid.
Before entering the expansion valve
Before passing through the condenser
After passing through the expansion valve or throttle valve
After passing through the condenser
Which of the following changes the state of refrigerant from being a superheated vapor to saturated and then to a subcooled liquid
Condenser
Compressor
Evaporator
Metering device
Which of the following describes the saturation temperature?
It is the point where the ice starts to melt
The temperature at which a fluid boils or condenses. It varies with pressure
It is the same as critical point for a gas
The temperature at which a fluid boils or condenses. It is independent of pressure
What environmental effect does a refrigerant have when it forms an explosive mixture when the concentration in air is between 16% to 25%?
GWP
Flammability
TWA
ODP
STEL
Which of the following does the term latent heat describe when referring to a refrigerant?
The heat required to superheat the refrigerant gas
The heat required to raise the liquid temperature to boiling point
The temperature
Heat required to cause evaporation at constant boiling temperature and pressure
What are the disadvantages of ammonia as a refrigerant?
It is toxic
It can only be used on very large refrigeration systems
It cannot be used in refrigeration systems with screw compressor
It is expensive
The current Refrigerants in Marine use such as R404A, R410a and R134a belongs to which group of Refrigerants?
HFCs
FCs
CFCs
HCs
HCFCs
Which of the following is an indication or measurement of the relative heat intensity of a body or a substance?
Subcooling
Temperature
Vapor quality
Enthalpy
Pressure
P/H Diagram
The refrigerant enters the metering device as________ ? Select the best answer
Superheated vapor
Subcooled liquid
Superheated liquid
Subcooled vapor
This is a type of refrigerant which is non-flammable, does not cause ozone depletion and very low toxicity index and available in large quantities at a low cost but has a low efficiency and high operating pressure. Select the best answer.
HCFCs
HCs
FCs
CO2
Ammonia
Which of the following is the correct definition of Subcooling?
Lowering in temperature of the liquid refrigerant
Lowering in temperature of the vapor refrigerant
Correct definition is supercooling.
Lowering in temperature of the saturated refrigerant
Which of the following group of refrigerants which are harmless to the Ozone Layer and does not have any direct greenhouse effect but are highly flammable?
HCFCs
FCs
HCs
HFCs
Which of the following was added to MARPOL Annex VI in 2011 to reduce GHG by at least 50% by 2050?
Chapter IV
Chapter III
Chapter V
None of the alternatives
Which of the following procedures is use when unwanted gases and moisture is removed from the refrigeration system?
Recovery
Vacuum
Pump down
Abandonment
Which of the following describes a temperature below the saturation temperature?
Superheat
Subcooling
Enthalpy
Which of the following is the correct definition of Super-heat?
Increase in temperature of saturated refrigerant
Increase in temperature of vapor refrigerant
Increase in temperature of liquid refrigerant
Supercool minus sub heat divided by two
Which of the following is the ratio of perpendicular force to area or the stress at a point within a confined fluid?
Pressure
Latent heat
Temperature
Enthalpy
The liquid tube connects the condenser to which of the following?
Compressor
Metering Device
Accumulator
Reversing valve
The bank of tubes at the back of domestic refrigerator are______?
Capillary tubes
Condenser tubes
Refrigerant cooling tubes
Evaporator tubes
Which of the following is the most important chemical properties of refrigerants? It should be non-poisonous to humans and food stuff.
Oil solubility
Toxicity
Reactivity
Low water solubility
The capillary tube as an expansion device is used in_____________?
Room air conditioners
Domestic refrigeration
Water coolers
All of the alternatives
Which of the following has the maximum ozone depletion potential in the atmosphere?
All of the alternatives
Chlorine
Carbon
Fluorine
The pressure at the inlet of a refrigerant compressor is called?
Back pressure
Suction pressure
Critical pressure
Discharge pressure
Which of the following is a part of the refrigerating system that prevents liquid refrigerant from flowing into the suction line and into the compressor.
Filter drier
Accumulator
Liquid receiver
Sight glass
Oil separator
Which of the following components are parts of the high-pressure side in a refrigeration system?
A. Expansion valve, evaporator, suction line
B. Discharge line, condenser, expansion valve
None of the alternatives
In Fahrenheit, the boiling point of water is___________?
100 degrees
221 degrees
112 degrees
212 degrees
Which of the following is the result of dividing the volume per mass unit? It is the opposite of density
Specific volume
P/H Diagram
Subcooling
Enthalpy
Which evaporator coil is used for quickly storing products below freezing temperatures?
Medium temperature coils
Low temperature coils
High temperature coils
Ultra Low temperature coils
Which of the following components keeps the refrigerant circulating through the system?
Expansion Valve
Compressor
Condenser
Evaporator
Which of the following is a part of the refrigerating system that acts as a storage for liquid refrigerant and ensures only liquid refrigerant is entering the expansion device?
Filter drier
Oil separator
Sight glass
Liquid receiver
Accumulator
The condenser is found downstream after the______? Select the best answer.
Evaporator
Compressor
Receiver
Metering device
Which evaporator coil is used for storing products above freezing temperatures?
Ultra Low temperature coils
Low temperature coils
Medium temperature coils
High temperature coils
Which of the following Group of Refrigerants which does not contain chlorine but still damage the environment because they are greenhouse gases?
HCFCs
CO2
HFCs
FCs
CFCs
Ammonia
Which of the disposing procedures is use when a partial or complete refrigerant is removed from the system and later re-injected; or when the system is converted to run with a new refrigerant or when the equipment is dispose of?
Pump down
Recovery
Abandonment
Vacuum
Which of the following describes the condition of a fluid at its boiling point?
P/H Diagram
Specific volume
Saturation
Which of the following indicates refrigerant undercharge?
Compressor running continuously/ high receiver level/ low temperature in the refrigerated room
Compressor running continuously/ low head pressure/ high head pressure
Continuous running of compressor/ vapor bubbles in the liquid sight glass/ low head pressure
Compressor running continuously/ vapor bubbles in the liquid sight glass/ high receiver level
Which of the following is the most likely answer when an Oil Separator may no longer be required in refrigeration system?
Refrigerant and oil are miscible at all the pressures and temperatures
Refrigerant and oil are immiscible at all the pressures and temperatures
Refrigerant and oil are miscible at condensation pressures and temperatures
EEDI is the technical measure adopted by IMO to reduce which of the following?
ODP
SOx
GWP
NOx
Which of the following are Crankcase heaters used for?
Operate on induced voltage from the stator windings
Allow proper oil migration
Drive liquid refrigerant out of the compressor
Regulates the temperature
Which of the following chemical properties of refrigerants which must not have any reaction to materials used in Refrigeration Cycle?
Toxicity
Low water solubility
Oil solubility
Reactivity
Which of the following Group of Refrigerants which is known to contribute to the greenhouse gas effect? The production of these ceased in 1994.
HCFCs
HCs
HFCs
FCs
Ammonia
CO2
CFCs
What is the definition of refrigeration?
The addition of cooling
The replacement of heat
The removal of heat
The removal and relocation of heat
Which of the following is referred to dryness fraction or the state of a cooling medium?
Temperature
Vapor quality
P/H Diagram
Which of the following is the correct statement for R600a Refrigerant?
It is flammable
It is a natural refrigerant
HC refrigerant
HC refrigerant
It does not cause any greenhouse effect
All statements are correct
None of the statements are true
Which of the following controls the temperature inside the Ships Meat Room or Vegetable Room? Select the correct response:
By thermostatic valves
By continuous ventilation of the evaporator blower
By temperature sensors
All of the alternatives
Which of the following indicates the refrigerants various thermodynamic states? Select the correct response:
P/H Diagram
Temperature
Latent heat
MARPOL Annex VI Prevention of Air Pollution from Ships was entered into force on which date? Select the correct response:
May 18, 2005
December 31, 1988
July 1, 2013
May 19, 2005
Which of the following is the sum of the internal energy and the product of the pressure and volume of a thermodynamic system? Select the correct response:
Enthalpy
Superheat
Subcooling
P/H Diagram
The refrigerant exits the compressor as high pressure, high temperature _______? Select the correct response:
Superheated vapor
Superheated liquid
Subcooled liquid
Subcooled vapor
Which of the following activates and trips the compressor when the discharge side pressure increases above the limit value? The Reset to this fault is to be done Manually. Select the correct response:
Temperature Sensor
High Pressure Control
Low Pressure Control
Overload Protector
Compressor Winding Fault switch
Which of the following is a part of the refrigerating system that maintains the internal cleanliness that traps impurities such as dirt, water or moisture? Select the correct response:
Filter drier
Oil separator
Accumulator
Sight glass
Liquid receiver
Which of the following is an example of Chlorofluorocarbons that has been banned from being use since the 90s? Select the correct response:
R600
R123
R22
R12
None of the alternatives
Which of the following is the quantity of heat absorbed or released by a substance undergoing a change of state such as ice changing to water at constant temperature and pressure?
Temperature
Enthalpy
Pressure
Latent heat
The refrigeration cycle is the Reverse of The Rankine Cycle.
False
Neither
True
Which of the following allows the refrigerant to lower in pressure, expand, and lower in temperature?
Evaporator
Condenser
Liquid line sight
Accumulator
Expansion valve
Reversing valve
Which of the following are equal to 1 atmospheric pressure?
All of the alternatives
1.01325 Bar
760 Torr
760 mmHg
14.7 PSI
Which of the following is the right definition of Air conditioning?
Ventilating
Dehumidifying
Cooling
All of the alternatives
Name three (3) main processes by which objects can become colder.
Refrigerant, Air conditioning, Absorption
Convection, Sublimation, Radiation
Radiation, Conduction, Convection
Evaporation, Condensation, Sublimation
Based on the picture shown, which of the following is the correct term for this type of compressor?
Recovery pump
Air, gas, vapor pump
Moisture removal pump
Vacuum
Evaporator
Condensation
Compression
Evaporation
Evaporator
Condensation
Expansion
Evaporation
Evaporator
Condensation
Expansion
Evaporation
Evaporator
Condensation
Expansion
Evaporation
This is the area at which the temperature is lower than the saturation temperature for the pressure range in question. Select the best answer.
Superheated gas
Liquid and gas mixture
Saturated vapor
Saturated liquid
CP
Subcooled liquid
Based on the picture shown, which of the following is the correct term for this type of compressor?
Semi hermetic compressor
Scroll compressor
Reciprocating compressor
Hermetic compressor
Based on the picture shown, which of the following position closes the valve and shuts off flow through the system at that point while remaining open to the port?
Back seat
Front seat
Mid seat
Front view
Based on the picture shown, which of the following position will provide flow in all directions. This position is ideal for vacuum and recovery with the system off.
Mid seat
Front seat
Back seat
Mid-range
Based on the picture shown, which of the following position provides full operational flow. Through the valve body but is closed to the access port. Select the correct response:
Mid seat
Front seat
Back seat
Mid-range
Based on the picture shown, which of the following is the correct term for this type of compressor?
Scroll
Semi-hermetic reciprocating pump
Hermetic
This is the area at which the gas has a higher temperature than the saturaton temperature at that pressure. Select the best answer.
Subcooled liquid
Saturated liquid
Liquid and gas mixture
Saturated vapor
Superheated gas
This is the area at which the refrigerant can change from liquid to gas and vice versa. Select the best answer. Select the correct response:
Subcooled liquid
Saturated liquid
Liquid and gas mixture
Saturated vapor
Superheated gas
Critical point
This is the area at which the refrigerant cannot be condensed, no mater how high the pressure. Therefore, compression normally operate at temperature below this point.
Subcooled liquid
Saturated liquid
Liquid and gas mixture
Saturated vapor
Superheated gas
Critical point
Based on the picture shown, which of the following is the correct term for this type of compressor?
Hermetic Compressor
Scroll Compressor
Semi-Hermetic
Centrifugal Compressor
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