AC 432 Refrigeration Systems
-
In most cases, the refrigerant leaving the evaporator must be ____ percent vapor.
About This Quiz
Refrigeration is used in different appliances around us, most commonly in refrigerators in our houses and places of work. How conversant are you with the refrigeration system, functionality and how to repair broken parts? Give this test on the system a try and polish up what you have forgotten before the finals.
Quiz Preview
- 2.
In a water-cooled condenser, the leaving water temperature is normally ____°F lower than the condensing temperature of the refrigerant.
Explanation
In a water-cooled condenser, the leaving water temperature is normally 10°F lower than the condensing temperature of the refrigerant. This temperature difference is necessary to ensure efficient heat transfer between the refrigerant and the water. By maintaining a lower water temperature, the condenser can effectively remove heat from the refrigerant, allowing it to condense and convert back into a liquid state. This helps in maintaining the overall cooling efficiency of the system.Rate this question:
- 3.
The automatic expansion valve maintains a constant ____.
Explanation
The automatic expansion valve is designed to regulate and maintain a constant pressure. It ensures that the pressure in the system remains consistent, preventing any fluctuations that could affect the performance or efficiency of the system. By maintaining a constant pressure, the valve helps to ensure optimal operation and stability in various applications such as refrigeration or air conditioning systems.Rate this question:
- 4.
Refrigerant entering the evaporator is approximately ____% liquid.
Explanation
The correct answer is 75 because the evaporator is the part of the refrigeration system where the refrigerant absorbs heat and evaporates. As the refrigerant enters the evaporator, it is in a liquid state. Therefore, approximately 75% of the refrigerant entering the evaporator is in liquid form.Rate this question:
- 5.
The TX valve maintains a constant ____.
Explanation
The TX valve maintains a constant superheat temperature. The superheat temperature refers to the temperature of the refrigerant vapor above its boiling point in the evaporator coil. The TX valve regulates the flow of refrigerant into the evaporator coil to ensure that the superheat temperature remains constant. This is important for the efficient operation of the refrigeration system and to prevent any damage to the compressor.Rate this question:
- 6.
The low form of plant life that grows in condenser water is ____.
Explanation
The low form of plant life that grows in condenser water is algae. Algae are simple, non-flowering plants that can grow in various aquatic environments, including condenser water. They are capable of photosynthesis and can thrive in moist and nutrient-rich conditions. The presence of algae in condenser water can cause problems such as clogging, reduced heat transfer efficiency, and corrosion. Therefore, it is important to regularly monitor and control algae growth in condenser water systems.Rate this question:
- 7.
As a rule of thumb, the temperature of the evaporator should be about ____ °F colder than the box temperature.
Explanation
The temperature of the evaporator should be about 15°F colder than the box temperature. This temperature difference ensures that the evaporator can effectively absorb heat from the box and maintain the desired temperature. If the evaporator temperature is not sufficiently colder than the box temperature, the cooling process may be inefficient and the desired temperature may not be achieved. Therefore, maintaining a temperature difference of 15°F helps optimize the cooling efficiency and ensures proper temperature control.Rate this question:
- 8.
An evaporative condenser uses ____ and ____ as the transfer medium for system heat.
Explanation
An evaporative condenser uses air and water as the transfer medium for system heat. The air absorbs heat from the condenser coils, causing the refrigerant to condense and release heat. The water is then used to cool down the hot refrigerant and remove the heat from the system. This process allows for efficient heat transfer and helps in the cooling of the system.Rate this question:
- 9.
If an air-cooled condenser's fan motor stops running, the heat pressure will ____ and the amount of subcooling will ____.
Explanation
If an air-cooled condenser's fan motor stops running, it will result in a decrease in airflow over the condenser coils. This decrease in airflow will cause the heat pressure to increase since the condenser coils will not be able to dissipate heat effectively. Additionally, the decrease in airflow will also lead to a decrease in subcooling, which refers to the temperature decrease of the refrigerant below its saturation point. Therefore, the correct answer is that the heat pressure will increase and the amount of subcooling will decrease.Rate this question:
- 10.
In order for a flooded condenser type head pressure control system to operate, a device called a ____ has to be added to the system because of the extra refrigerant.
Explanation
A receiver is a device that is added to a flooded condenser type head pressure control system to accommodate the extra refrigerant. This is necessary because the flooded condenser system operates by having excess refrigerant in the condenser, which helps to maintain a constant head pressure. The receiver acts as a storage tank for the excess refrigerant, allowing it to be stored and released as needed to maintain the desired head pressure in the system. Without a receiver, the system would not be able to properly control the head pressure and may result in inefficient operation or damage to the equipment.Rate this question:
- 11.
The correct term for a coil using a low side float is ____.
Explanation
A coil that uses a low side float is referred to as "flooded." This means that the coil is submerged in the refrigerant, allowing for efficient heat transfer. The low side float helps maintain the desired level of refrigerant in the coil, ensuring optimal performance.Rate this question:
- 12.
One large problem designer's face when designing air-cooled refrigeration and air conditioning equipment is a changing ambient from the changing seasons.
-
True
-
False
Correct Answer
A. TrueExplanation
The statement is true because the changing seasons result in varying ambient temperatures, which can pose a challenge for designers of air-cooled refrigeration and air conditioning equipment. As the ambient temperature fluctuates, the equipment needs to be able to adjust and maintain the desired temperature efficiently. Designers must consider these changing conditions to ensure that the equipment functions effectively in different seasons.Rate this question:
-
- 13.
As the evaporator load increases, an automatic expansion valve will ____ to reduce the evaporator pressure while a thermostatic expansion valve will ____ to reduce the evaporator superheat.
Correct Answer
close, openExplanation
As the evaporator load increases, an automatic expansion valve will close to reduce the evaporator pressure. This is because a closed valve restricts the flow of refrigerant into the evaporator, reducing the pressure and preventing excess refrigerant from entering the system. On the other hand, a thermostatic expansion valve will open to reduce the evaporator superheat. Opening the valve allows more refrigerant to flow into the evaporator, increasing the cooling capacity and reducing the superheat of the refrigerant leaving the evaporator.Rate this question:
- 14.
The refrigerant in the evaporator must be colder than the air passing over it for heat to transfer to the evaporator.
-
True
-
False
Correct Answer
A. TrueExplanation
This statement is true because heat transfer occurs from a higher temperature region to a lower temperature region. In the case of an evaporator, heat is transferred from the air passing over it to the refrigerant. Therefore, the refrigerant in the evaporator must be colder than the air for heat transfer to occur.Rate this question:
-
- 15.
Low suction pressures, iced coils, short-cycling, and inefficient cooling can also result from low head pressures.
-
True
-
False
Correct Answer
A. TrueExplanation
Low suction pressures, iced coils, short-cycling, and inefficient cooling can indeed result from low head pressures. When the head pressure is low, it means that there is not enough refrigerant being condensed in the condenser. This can lead to a decrease in the suction pressure, causing the coils to ice up and the system to short-cycle. Additionally, the cooling efficiency of the system will be compromised, resulting in inefficient cooling. Therefore, the statement is true.Rate this question:
-
- 16.
The two primary functions of an evaporator are to remove ____ and ____ from the refrigerated space.
Correct Answer
moisture, heat
heat, moistureExplanation
The correct answer is "moisture, heat". An evaporator is a component in a refrigeration system that absorbs heat from the refrigerated space and removes moisture from the air. As the refrigerant evaporates, it absorbs heat from the surrounding air, thereby cooling the space. At the same time, the evaporator also helps in dehumidifying the air by condensing the moisture present in it. Therefore, the primary functions of an evaporator are to remove moisture and heat from the refrigerated space.Rate this question:
- 17.
When the velocity of the air moving over an evaporator is slow, the "air film" acts as an insulator and slow the rate of heat exchange.
-
True
-
False
Correct Answer
A. TrueExplanation
When the velocity of the air moving over an evaporator is slow, the "air film" refers to a layer of air that forms on the surface of the evaporator. This air film acts as an insulator, meaning that it inhibits the transfer of heat between the evaporator and the air. As a result, the rate of heat exchange is slowed down. Therefore, the statement is true.Rate this question:
-
- 18.
Evaporative condensers operate more efficiently in climates where the wet bulb temperature is a great deal lower than the dry bulb temperature.
-
True
-
False
Correct Answer
A. TrueExplanation
Evaporative condensers operate more efficiently in climates where the wet bulb temperature is significantly lower than the dry bulb temperature because the condenser uses the evaporation of water to cool the refrigerant. When the wet bulb temperature is lower, the water evaporates more easily, resulting in better cooling efficiency. This means that the condenser can effectively remove heat from the refrigerant, allowing the system to function optimally.Rate this question:
-
- 19.
If a low temperature evaporator is forming excess ice, which of the following could be a possible problem?
-
The evaporator fan motor is defective.
-
The unit is not staying in defrost long enough.
-
The defrost heater is defective.
-
All of the above are correct.
Correct Answer
A. All of the above are correct.Explanation
If a low temperature evaporator is forming excess ice, all of the given options could be possible problems. A defective evaporator fan motor can cause insufficient air circulation, leading to ice formation. If the unit is not staying in defrost long enough, the ice on the evaporator may not melt completely, resulting in excess ice buildup. A defective defrost heater can also prevent proper melting of ice during the defrost cycle, leading to excess ice formation. Therefore, all of the mentioned issues could contribute to the formation of excess ice on the low temperature evaporator.Rate this question:
-
- 20.
A typical evaporator operating temperature in an air-conditioning system is ____.
-
40°F
-
55°F
-
75°F
-
200°F
Correct Answer
A. 40°FExplanation
A typical evaporator operating temperature in an air-conditioning system is 40°F because this temperature allows for efficient cooling of the air. At this temperature, the evaporator coil can effectively absorb heat from the surrounding air, causing the refrigerant to evaporate and cool the air passing through the system. This temperature is also suitable for maintaining a comfortable indoor environment without causing excessive cooling or freezing of the air.Rate this question:
-
- 21.
A typical superheat for an evaporator operating under normal conditions would be ____.
-
14 to 16°F
-
4 to 6°F
-
8 to 12°F
-
6 to 8°F
Correct Answer
A. 8 to 12°FExplanation
A typical superheat for an evaporator operating under normal conditions would be 8 to 12°F. Superheat is the temperature difference between the actual temperature of the refrigerant vapor and its saturation temperature at a given pressure. It is important to have a certain amount of superheat in the evaporator to ensure that the refrigerant is fully vaporized before it leaves the evaporator. A superheat of 8 to 12°F is considered normal and allows for efficient heat transfer and prevents liquid refrigerant from entering the compressor.Rate this question:
-
- 22.
The capacity of an evaporator is affected by ____.
-
The saturation pressure of the low side of the system
-
The saturation pressure of the high side of the system
-
The amount of evaporator superheat
-
All of the above
Correct Answer
A. All of the aboveExplanation
The capacity of an evaporator is affected by all of the above factors. The saturation pressure of the low side of the system determines the temperature at which the refrigerant evaporates, thus affecting the heat transfer process. Similarly, the saturation pressure of the high side of the system affects the condensing temperature and the overall efficiency of the system. Additionally, the amount of evaporator superheat, which is the temperature rise above the refrigerant's saturation temperature, also impacts the evaporator's capacity as it affects the heat transfer rate. Therefore, all of these factors play a role in determining the capacity of an evaporator.Rate this question:
-
- 23.
The condenser in a refrigeration system ____.
-
Desuperheats the vapor from the compressor
-
Condenses the vapor from the compressor
-
Subcools the liquid refrigerant before it leaves the condenser
-
All of the above
Correct Answer
A. All of the aboveExplanation
The condenser in a refrigeration system performs multiple functions. Firstly, it desuperheats the vapor from the compressor, removing excess heat and reducing the temperature. Secondly, it condenses the vapor, converting it back into a liquid state. Lastly, it subcools the liquid refrigerant before it leaves the condenser, further lowering its temperature. Therefore, the correct answer is "all of the above" as the condenser performs all these tasks in a refrigeration system.Rate this question:
-
- 24.
If a spring pressure of a water regulating valve is increased, the system head pressure will also increase.
-
True
-
False
Correct Answer
A. TrueExplanation
Increasing the spring pressure of a water regulating valve will result in an increase in the force exerted by the valve on the water flowing through it. This increased force will cause the valve to close more tightly, reducing the flow rate and increasing the system head pressure. Therefore, it is true that increasing the spring pressure of a water regulating valve will also increase the system head pressure.Rate this question:
-
- 25.
When the quantity of refrigerant flow to an evaporator is reduced, the amount of superheat in the vapor leaving the coil will ____.
Correct Answer
riseExplanation
When the quantity of refrigerant flow to an evaporator is reduced, there will be less refrigerant available to absorb heat from the surroundings. As a result, the evaporator coil will not be able to remove as much heat from the system, leading to an increase in the temperature of the refrigerant leaving the coil. This increase in temperature is known as superheat, so when the quantity of refrigerant flow is reduced, the amount of superheat in the vapor leaving the coil will rise.Rate this question:
- 26.
Condensing temperatures in an air-cooled condensing unit can be reduced by ____.
-
Increasing the condensing surface area
-
Increasing the cfm through the condenser
-
Decreasing the temperature of the air entering the condenser
-
All of the above
Correct Answer
A. All of the aboveExplanation
By increasing the condensing surface area, more heat can be dissipated, resulting in lower condensing temperatures. Similarly, increasing the cfm (cubic feet per minute) through the condenser increases the rate of heat transfer, leading to lower temperatures. Additionally, decreasing the temperature of the air entering the condenser provides a cooler environment for heat exchange, further reducing condensing temperatures. Therefore, all of these actions can contribute to reducing the condensing temperatures in an air-cooled condensing unit.Rate this question:
-
- 27.
A defrost system that pipes the compressor discharge vapor directly to the evaporator is called a ____ type.
Correct Answer
hot gas defrostExplanation
A defrost system that pipes the compressor discharge vapor directly to the evaporator is called a hot gas defrost type. In this type of system, the hot gas from the compressor is used to heat up the evaporator coil, melting any ice or frost that has accumulated on it. This hot gas is then condensed back into a liquid state and returned to the compressor to continue the refrigeration cycle. This method is efficient and helps to quickly defrost the evaporator, allowing it to resume normal cooling operations.Rate this question:
- 28.
The two pressures that push to close a thermostatic expansion valve are the ____ pressure and the ____ pressure.
Correct Answer
spring, evaporatorExplanation
The spring pressure in a thermostatic expansion valve acts as a force that pushes to close the valve. This pressure is created by the compression of the spring within the valve. The evaporator pressure, on the other hand, refers to the pressure within the evaporator coil of a refrigeration system. This pressure also contributes to the closing of the expansion valve as it creates a back pressure that helps to keep the valve closed. Therefore, both the spring pressure and the evaporator pressure work together to push the thermostatic expansion valve to close.Rate this question:
- 29.
A stamped plate evaporator usually does not use a fan to move air across it.
-
True
-
False
Correct Answer
A. TrueExplanation
A stamped plate evaporator is designed in such a way that it promotes natural convection for heat transfer. It consists of multiple thin plates with small channels or passages for the refrigerant to flow through. These plates are typically arranged in a stack, allowing for a larger surface area for heat exchange. Due to this design, a fan is not required to move air across the evaporator as the natural convection currents created by the temperature difference between the refrigerant and the surrounding air are sufficient for efficient heat transfer. Therefore, the statement "A stamped plate evaporator usually does not use a fan to move air across it" is true.Rate this question:
-
- 30.
Hard starting may also occur in a low ambient conditions causing low head pressures.
-
True
-
False
Correct Answer
A. TrueExplanation
Hard starting refers to difficulties in starting a machine or engine. In low ambient conditions, such as cold weather, the head pressures in the system may be low. This can result in hard starting because the system may not be able to build up the necessary pressure to start properly. Therefore, the statement that hard starting may occur in low ambient conditions causing low head pressures is true.Rate this question:
-
- 31.
If an evaporator has a pressure drop of 10 psig and the low side pressure is 15 psig, what is the pressure at the inlet of the evaporator?
-
10 psig
-
25 psig
-
15 psig
-
5 psig
Correct Answer
A. 25 psigExplanation
The pressure at the inlet of the evaporator is 25 psig because the pressure drop is subtracted from the low side pressure. In this case, the pressure drop is 10 psig, so when it is subtracted from the low side pressure of 15 psig, the result is 25 psig.Rate this question:
-
- 32.
A large capacity evaporator would probably have ____.
-
Stainless steel tubing
-
An excess of liquid refrigerant
-
An excess of vapor refrigerant
-
Multiple refrigerant circuits
Correct Answer
A. Multiple refrigerant circuitsExplanation
A large capacity evaporator would probably have multiple refrigerant circuits. This is because a larger evaporator requires more refrigerant to be evaporated in order to cool a larger space or handle a higher cooling load. Having multiple refrigerant circuits allows for better distribution of the refrigerant and helps to ensure efficient and effective cooling throughout the evaporator.Rate this question:
-
- 33.
If an R-12 refrigeration system has its air-cooled condensing unit on a 100°F roof and the condenser outlet temperature (refrigerant) is 115°F, with how much subcooling is the condenser operating?
-
30°F
-
15°F
-
100°F
-
130°F
Correct Answer
A. 15°FExplanation
The condenser is operating with 15°F of subcooling. Subcooling is the temperature difference between the liquid refrigerant leaving the condenser and its saturation temperature. In this case, the condenser outlet temperature is 115°F, which is 15°F higher than the saturation temperature. Therefore, the condenser is operating with 15°F of subcooling.Rate this question:
-
- 34.
The refrigerant in a condenser in a refrigeration system ____.
-
Absorbs heat
-
Gives up heat
-
Changes to a vapor
-
Is under lower pressure than the evaporator
Correct Answer
A. Gives up heatExplanation
In a refrigeration system, the condenser is responsible for releasing heat from the refrigerant. As the refrigerant flows through the condenser, it undergoes a phase change from a high-pressure vapor to a high-pressure liquid. During this process, the refrigerant gives up heat to the surroundings, which allows it to cool down and condense. Therefore, the correct answer is "gives up heat."Rate this question:
-
- 35.
If an R-12 refrigeration system is operating with a 25.4 psig suction pressure, what is the evaporator superheat if the evaporator outlet temperature is 34°F?
-
9°F
-
59°F
-
34°F
-
25°F
Correct Answer
A. 9°FExplanation
The evaporator superheat is the difference between the actual evaporator outlet temperature and the saturation temperature at the corresponding evaporator pressure. In this case, the evaporator outlet temperature is given as 34°F and the suction pressure is given as 25.4 psig. By looking up the saturation temperature of R-12 at 25.4 psig, we can find that it is 25°F. Therefore, the evaporator superheat is 34°F - 25°F = 9°F.Rate this question:
-
- 36.
Mineral deposits in the water portion of a water-cooled condenser act as ____.
-
A conductor of heat
-
An insulator
-
A cleaning solution
-
They have no effect on the operation of the condenser.
Correct Answer
A. An insulatorExplanation
Mineral deposits in the water portion of a water-cooled condenser act as an insulator. This means that they hinder the transfer of heat between the water and the condenser. Insulators are substances that do not conduct heat well, so when mineral deposits build up in the condenser, they create a barrier that prevents efficient heat transfer. As a result, the condenser may become less effective in cooling the water, leading to decreased efficiency and potential operational issues.Rate this question:
-
- 37.
The desired water flow through a condenser connecting to a recirculating water system is 3 gallons per minute.
-
True
-
False
Correct Answer
A. TrueExplanation
The statement is true because it states that the desired water flow through a condenser connecting to a recirculating water system is 3 gallons per minute. This means that the condenser is designed to operate efficiently with a flow rate of 3 gallons per minute, indicating that any other flow rate may not be optimal for the system.Rate this question:
-
- 38.
If the application requires a coil design to operate below 32°F, there must be provision for ____.
-
Flooding the evaporator
-
Adding the evaporator
-
Defrost
-
Suction pressure control
Correct Answer
A. DefrostExplanation
If the application requires a coil design to operate below 32°F, there must be provision for defrost. This is because when operating at such low temperatures, ice can build up on the evaporator coil, reducing its efficiency and potentially causing damage. Defrosting is necessary to remove the ice buildup and ensure proper functioning of the coil.Rate this question:
-
- 39.
The shell and tube condenser is cleaned ____.
-
With a brush after removing the end caps
-
Only with chemicals
-
With compressed air
-
With a vacuum cleaner
Correct Answer
A. With a brush after removing the end capsExplanation
The shell and tube condenser is cleaned with a brush after removing the end caps. This is because the brush allows for effective scrubbing and removal of any debris or buildup inside the condenser tubes. Removing the end caps provides access to the tubes, making it easier to clean them thoroughly. Using a brush ensures a physical cleaning action, which can be more effective than solely relying on chemicals, compressed air, or a vacuum cleaner.Rate this question:
-
- 40.
A forced draft high temperature evaporator would ____.
-
Have its fins very close together
-
Not need to be defrosted
-
Need a hot gas defrost
-
Both a and b
Correct Answer
A. Both a and bExplanation
A forced draft high temperature evaporator would have its fins very close together and not need to be defrosted. This is because the close proximity of the fins allows for efficient heat transfer, preventing the formation of ice and frost. Additionally, the forced draft design ensures a continuous flow of air, further preventing the need for defrosting. Therefore, both options a and b are correct.Rate this question:
-
- 41.
If the waterflow is reduced, the temperature difference across a condenser will ____.
-
Increase
-
Decrease
-
Remain the same
-
Correspond to the evaporator saturation temperature
Correct Answer
A. IncreaseExplanation
When the waterflow is reduced in a condenser, it means that there is less water available to remove heat from the condenser. This leads to a decrease in the overall heat transfer rate, resulting in a higher temperature difference across the condenser. Therefore, the temperature difference across the condenser will increase when the waterflow is reduced.Rate this question:
-
- 42.
During the defrost cycle of a forced draft low temperature evaporator, the evaporator fan would ____.
-
Remain on to speed up the defrost
-
Turn off
-
Cycle with the condenser
-
Cycle with the compressor
Correct Answer
A. Turn offExplanation
During the defrost cycle of a forced draft low temperature evaporator, the evaporator fan would turn off. This is because during the defrost cycle, the heat from the defrost heaters is used to melt the ice that has accumulated on the evaporator coils. If the evaporator fan remains on, it would blow the warm air away from the coils, reducing the effectiveness of the defrosting process. Therefore, turning off the fan allows the heat to be concentrated on the coils, speeding up the defrosting process.Rate this question:
-
- 43.
Control of the head pressure in an air-cooled condenser is done by ____.
-
Cycling the condenser fan
-
Controlling dampers in the airstream through the condenser
-
Flooding the condenser with refrigerant
-
All of the above
Correct Answer
A. All of the aboveExplanation
The control of head pressure in an air-cooled condenser can be achieved through multiple methods. One way is by cycling the condenser fan, which adjusts the air flow and helps regulate the condenser temperature. Another method is by controlling dampers in the airstream through the condenser, which allows for better control of the air flow and heat transfer. Lastly, flooding the condenser with refrigerant can also help in controlling the head pressure. Therefore, all of the above options are correct ways to control the head pressure in an air-cooled condenser.Rate this question:
-
- 44.
If a high temperature evaporator is forming ice, which of the following is a possible problem?
-
Evaporator fan not running
-
Compressor not running
-
Condenser fan not running
-
No problem, ice formation normal
Correct Answer
A. Evaporator fan not runningExplanation
If a high temperature evaporator is forming ice, a possible problem could be that the evaporator fan is not running. The evaporator fan is responsible for circulating air over the evaporator coil, which helps to remove heat and prevent ice formation. If the fan is not running, the air flow will be restricted, causing the evaporator coil to become too cold and resulting in ice formation.Rate this question:
-
- 45.
Fewer fins per inch on an evaporator allow more ice to build between defrost cycle.
-
True
-
False
Correct Answer
A. TrueExplanation
Fewer fins per inch on an evaporator means that there is more space between the fins for ice to accumulate. This allows for more ice to build up between defrost cycles because there is more surface area available for ice formation. Therefore, the statement is true.Rate this question:
-
- 46.
A refrigeration system designed for the storage of flowers or candy is considered a ____ type.
-
High temperature
-
Medium temperature
-
Low temperature
-
Sharp freezing
Correct Answer
A. High temperatureExplanation
A refrigeration system designed for the storage of flowers or candy is considered a high temperature type because it is not meant to freeze or cool the items to extremely low temperatures. Instead, it is designed to maintain a slightly cooler temperature than the surrounding environment to prevent spoilage or melting, but not cold enough to freeze the products.Rate this question:
-
- 47.
A normally operating water-cooled condenser is operating with a 10° differential between water in and water out. If scale forms on the water tubes and the entering water is 85°F, which of the following is possible?
-
The outlet water will be 88°F.
-
The system head pressure will rise
-
The water regulating valve will close.
-
Both a and b are correct.
Correct Answer
A. Both a and b are correct.Explanation
Both options a and b are correct because when scale forms on the water tubes, it acts as an insulating layer, reducing the heat transfer efficiency. As a result, the outlet water temperature will increase, causing the outlet water to be 88°F instead of the usual 85°F. Additionally, the reduced heat transfer efficiency will cause the system head pressure to rise as the condenser struggles to remove heat effectively. Therefore, both a and b are possible outcomes in this scenario.Rate this question:
-
- 48.
An air-cooled condenser that is operating in a climate that has four distinct seasons must ____.
-
Have some type of head pressure control
-
Use a water regulating valve
-
Have a multi-circuit evaporator
-
Operate with zero degrees of subcooling
Correct Answer
A. Have some type of head pressure controlExplanation
An air-cooled condenser that is operating in a climate that has four distinct seasons must have some type of head pressure control because the temperature and humidity levels can vary greatly throughout the year. Head pressure control helps to maintain the condenser's operating pressure within a desired range, ensuring efficient heat transfer and preventing the condenser from becoming overworked or damaged. By adjusting the head pressure, the condenser can effectively cool the refrigerant and maintain optimal performance regardless of the changing outdoor conditions.Rate this question:
-
- 49.
The water circuit in shell and coil and coil-type tube-in-a-tube condensers must be cleaned ____.
-
By removing the end caps
-
With a brush
-
Chemically
-
By air pressure
Correct Answer
A. ChemicallyExplanation
The water circuit in shell and coil and coil-type tube-in-a-tube condensers must be cleaned chemically. This is because chemical cleaning is the most effective method to remove any buildup or deposits that may accumulate in the water circuit. Chemical cleaners are specifically designed to dissolve and remove scale, rust, and other contaminants, ensuring optimal performance and efficiency of the condenser.Rate this question:
-
Quiz Review Timeline (Updated): Mar 21, 2023 +
Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
-
Current Version
-
Mar 21, 2023Quiz Edited by
ProProfs Editorial Team -
Feb 18, 2010Quiz Created by
Azortex
Back to top