Industrial Refrigeration Book 1 - 18 edition

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

Where can a list of the proper PPE needed to safely perform a job task be found? A. SOPs and MPs B. Safety Data Sheet C. Risk management plan D. Hazardous material business plan.

A. SOPs and MPs

Which item does the expansion valve control? A. The flow of liquid into the evaporator. B. The pressure in the evaporator. C. The pressure in the receiver. D. The system operating pressure.

A. The flow of liquid into the evaporator.

Flash gas is __________ A. The gas created at the expansion device. B. The gas used to defrost evaporators that use gas defrost systems. C. The gas created anytime liquid refrigerant evaporates. D. A flammable refrigerant gas.

A. The gas created at the expansion device.

The latent heat of condensation of a substance is the same as __________ A. The latent heat of evaporation of the substance at the same pressure. B. The latent heat of freezing of the substance at the same pressure. C. The specific heat of the substance. D. The heat required to sublimate the substance.

A. The latent heat of evaporation of the substance at the same pressure.

Which of the following is responsible to determine if an area is considered confined space? A. The owner/employer B. The employee that is going to be working in the area C. The supervisor D. OSHA

A. The owner/employer

How much pressure does the pressure of trapped ammonia liquid change? A. 1 psi per 100° to 150°F increase. B. 100 to 150 psi per degree Fahrenheit increase. C. 1 psi per 100° to 150°F decrease. D. 100 to 150 psi per degree Fahrenheit decrease.

B. 100 to 150 psi per degree Fahrenheit increase.

Thirty-two psia equals __________ A. 46.7 psig. B. 17.3 psig. C. 3.2 in. Hg Vacuum. D. 760 mm Vacuum.

B. 17.3 psig.

SIRLOIN STEAK: 0.735 BTU/lb./°F A meat plant processes 100 animals a day with an average processed weight of 750 pounds of beef per animals. The meat must be cooled to 45°F from 85°F. How many BTUs must be removed in the cooling process? (Use specific heat of sirloin steak) A. 3,000,000 B. 2,205,000 C. 220,500 D. 55,125

B. 2,205,000

Convert -6.7 degrees C to Fahrenheit. A. 32°F B. 20°F C. -20°F D. -12°F

B. 20°F

Calculate the compression ratio for the R-22 system: (1) saturated suction pressure is 20 psig, (2) saturated discharge pressure is 175 psig, and (3) motor amps are 154. A. 8.75:1 B. 5.46:1 C. 1.13:1 D. 7.7:1

B. 5.46:1

A conventional mechanical refrigeration system is considered __________ A. An expendable refrigerant system. B. A closed loop system. C. An open loop system. D. A multi-loop system.

B. A closed loop system.

What kind of a measure is a ton of refrigeration? A. An amount in pounds. B. A rate of heat transfer in BTUs per unit of time. C. A quantity in BTUs. D. A measure of energy in BTUs per pound.

B. A rate of heat transfer in BTUs per unit of time.

Which of the answers below is an example of heat transfer by conduction? A. The sun's rays. B. A rod heated on one end becoming warm at the other end. C. Product being frozen in a blast freezer. D. Heat felt from a campfire when starting upwind.

B. A rod heated on one end becoming warm at the other end.

What are two refrigerants that are blended to create a new refrigerant with its own properties called? A. HCFC refrigerants. B. A zoetrope or an azeotrope. C. CFC refrigerants. D. Water-based refrigerants.

B. A zoetrope or an azeotrope.

How much can the pressure of trapped liquid increase per degree Fahrenheit of temperature increase? A. Between 50 and 100 psi B. Between 100 and 150 psi C. Between 180 and 190 psi D. Between 200 and 300 psi

B. Between 100 and 150 psi

Which refrigerant was the first to be phased out by Montreal Protocol? A. Ammonia B. CFC-12 C. HCFC-22 D. Sulfur-dioxide

B. CFC-12

Discharge temperature should not be so high it __________ A. Causes the evaporative condenser water to evaporate. B. Cause breakdown of the compressor lubricating oil. C. Heats up the suction port. D. Makes the refrigerants pump activate.

B. Cause breakdown of the compressor lubricating oil.

Double acting reciprocating compressors A. Compress the same gas twice with each stroke of the piston. B. Compress vapor on the fore stroke and the back stroke. C. Provide two stage compression with higher efficiency than separate compressors. D. Are compressors that can be used for either low stage or high stage operations.

B. Compress vapor on the fore stroke and the back stroke.

Refrigerant leaks are detected using A. Either a halide torch or sulfur stick on HCFCs. B. Either a sulfur stick on ammonia or electric leak detector for CFCs or HCFCs. C. Either a halide torch or sulfur stick on ammonia. D. Either a halide torch or litmus paper for ammonia.

B. Either a sulfur stick on ammonia or electric leak detector for CFCs or HCFCs.

In an operating ammonia refrigeration system, subcooled refrigerant can only be a __________ A. Solid. B. Liquid. C. Vapor. D. Combination of liquid and vapor.

B. Liquid.

Which of the following requires hot work permits? A. The local fire department B. OSHA regulations C. The HR department D. EPA regulations

B. OSHA regulations

When calculating the BTUs that have to be removed to change the temperature of a substance, what combination of the following is used? A. Pounds of substance, sensible heat, temperature. B. Pounds of substance, temperature difference, specific heat. C. Pounds of substance, heat of cooling, change of state. D. Pounds of substance, latent heat, heat of refrigeration.

B. Pounds of substance, temperature difference, specific heat.

Which refrigerant would have the lowest condensing pressure at 95°F condensing? A. R-717 B. R-134a C. R-507 D. HCFC-22

B. R-134a

Of the refrigerants listed below, which refrigerant has the highest mass flow requirement at the same evaporator and condensing temperature? A. R-717 B. R-404a C. HCFC-22 D. R-134a

B. R-404a

Under the same operating conditions, which refrigerant listed below has the greater refrigeration effect per pound? A. HCFC-22 B. R-717 C. R-134a D. R-507

B. R-717

What is the scale used to measure Fahrenheit temperature absolute? A. Extreme B. Rankine C. Celsius D. Kelvin

B. Rankine

Under normal conditions, an ammonia vessel A. Should be filled to 90% full of liquid. B. Should be filled to 80% full of liquid. C. Should be filled to 50% full of liquid. D. May be filled 100% full of liquid.

B. Should be filled 80% full of liquid.

What factor do you multiply the mass flow rate (lbs./min.) by to determine the vapor flow rate through the compressor. A. Density (lbs./cubic ft.) B. Specific volume (cubic ft./lb.) C. Capacity (BTU/min.) D. Velocity (ft./min.)

B. Specific volume (cubic ft./lb.)

If a liquid below its saturation temperature, what is its condition? A. Superheated B. Subcooled C. Saturated D. Vaporized

B. Subcooled

Fire watchers must be trained in __________ A. Recognizing potential combustible material locations at the facility. B. The use of fire extinguishing equipment. C. CPR. D. Confined space entry requirements.

B. The use of fire extinguishing equipment.

What is one positive characteristic of most halocarbon refrigerants? A. They are always non-toxic and safe. B. They are not generally flammable. C. They are low cost. D. They have a much higher latent heat of boiling than ammonia.

B. They are not generally flammable.

Discharge vapor from all compressors A. Must go directly to a condenser. B. Will contain some level of superheat. C. Must be monitored to ensure it does not condense. D. May be subcooled to improve efficiency.

B. Will contain some level of superheat.

Which of the following statements is true? A. 10 psia is a greater pressure than 10 psig. B. 10 psig is equal to 10 psia. C. 10 psig is greater pressure than 10 psia. D. 10 psig and 10 psia use different scales therefore cannot be compared in this way.

C. 10 psig is greater pressure than 10 psia.

The published lower explosive limit for ammonia is A. 5% B. 10% C. 16% D. 25%

C. 16%

What is the freezing point of water? A. -32°F B. 32°C C. 32°F D. 0°F

C. 32°F

OSHA regulations require persons wearing respiratory protective equipment to have __________ A. No mustache B. Rubber boots and gloves C. A medical evaluation to confirm fitness to wear the PPE D. Side shielded safety glasses.

C. A medical evaluation to confirm fitness to wear the PPE

Lockout/Tagout required __________ A. When work is done inside the building. B. Only when moving parts can cut off body parts or smash fingers. C. Anytime work exposes an employee to hazardous energy. D. When work is done on the roof.

C. Anytime work exposes an employee to hazardous energy.

Refrigerant absorbs the most heat when __________ A. Being superheated. B. Being sub cooled. C. Changing from a liquid to a vapor. D. Changing from a vapor to a liquid.

C. Changing from a liquid to a vapor.

Three factors to consider when choosing a refrigerant are? A. Molecular weight, availability, and safety. B. Refrigeration effect, cost, and viscosity. C. Cost, availability, and safety. D. Cost, availability, and refrigeration coefficient.

C. Cost, availability, and safety.

What does the first Law of Thermodynamics state? A. Energy content only changes with a change in temperature. B. Energy is created when a substance is heated up. C. Energy cannot be created or destroyed. D. Total energy in a substance is a function of its physical size.

C. Energy cannot be created or destroyed.

What are the four necessary components of a mechanical refrigeration system? A. Evaporator, condensor, receiver, compressor B. King Valve, gauges, thermometers, amp meter C. Expansion device, evaporator, compressor, condenser D. Evaporator, condensor, King Valve, compressor.

C. Expansion device, evaporator, compressor, condenser

Heat energy always flows __________ A. From a substance with more heat energy to a substance with less heat energy. B. Regardless of temperature C. From an object at a higher temperature to an object at a lower temperature. D. From a liquid to a vapor.

C. From an object at a higher temperature to an object at a lower temperature.

What is one advantage to having evaporator pressures higher than atmospheric pressure? A. Gauges scaled for psia are more expensive than gauges scaled for psig. B. Higher pressures in the evaporator mean colder room temperatures. C. Higher pressures keep air out of the system. D. There is no advantage to evaporator pressures that are higher than atmospheric.

C. Higher pressures keep air out of the system.

Latent heat __________ A. Is measured using a pressure gauge. B. Can be sensed by using a thermometer. C. Is heat energy that causes a change of state but does not cause a change in temperature. D. Is heat energy that causes a change in temperature but does not cause a change of state.

C. Is heat energy that causes a change of state but does not cause a change in temperature.

Latent heat of vaporization __________ A. Is calculated using temperature. B. Is always going to raise the temperature of the liquid it is trying to boil. C. Is the heat energy required to cause a liquid to become a vapor. D. Is the same for all liquids.

C. Is the heat energy required to cause a liquid to become a vapor.

The primary reason for concern about HCFC-22 concentration in an engine room is A. Toxicity B. Explosion potential C. Oxygen deprivation D. Reactivity with other chemicals.

C. Oxygen deprivation

Which refrigerant requires the largest compressor displacement per ton? A. R-717 B. R-507 C. R-134a D. HCFC-22

C. R-134a

A vapor can NOT be __________ A. Compressed. B. Superheated. C. Subcooled. D. Saturated.

C. Subcooled.

What is the relationship between temperature difference and heat flow? A. There is no relationship between temperature and heat flow. B. The greater the temperature difference, the slower heat flows. C. The greater the temperature difference, the more rapid the heat flows. D. The more rapidly the heat flows, the greater the temperature increases.

C. The greater the temperature difference, the more rapid the heat flows.

Which of the answers below is an example of pressure drop? A. The difference in pressure due to the refrigerant "dropping" in a vertical pipe riser. B. In a compressor, the difference in pressure when the piston is at top dead center and bottom dead center. C. The loss of pressure as a fluid moves down the pipe due to the interaction of the fluid and the inner walls of the pipe. D. The change in pressure between the condenser outlet and the high pressure receiver.

C. The loss of pressure as a fluid moves down the pipe due to the interaction of the fluid and the inner walls of the pipe.

Why does the refrigerant in the condenser change state from vapor to liquid? A. The pressure is decreased by the compressor. B. The refrigerant runs down into the receiver. C. The refrigerant loses heat energy to the surrounding environment. D. The fans increase the pressure to above the saturation.

C. The refrigerant loses heat energy to the surrounding environment.

Pressure is a measure of __________ A. The action seen from the attraction of gravity. B. Weight. C. The relationship of a force being applied over a given area. D. The distance between the top of the piston and the discharge valve of a reciprocating compressor.

C. The relationship of a force being applied over a given area.

As the ratio between the evaporator and condensing pressure increases, A. The theoretical discharge temperature decreases. B. The theoretical discharge temperature stays the same. C. The theoretical discharge temperature increases. D. Both theoretical discharge and evaporating temperature increase.

C. The theoretical discharge temperature increases.

A cartridge type gas mask may legally be used for personal protection from ammonia exposure when? A. The type of the hazard is known but the concentration is unknown. B. The type of the hazard is unknown, but the concentration is unknown. C. The type of the hazard is known, but the concentration is known and less than IDLH. D. Cartridge type gas masks are not approved for use with the ammonia under any circumstance.

C. The type of the hazard is known, and the concentration is known and is less than IDLH

What is the basic idea behind the design of the hermetic compressor? A. To avoid buying two separate pieces of equipment. B. To avoid slugging. C. To avoid allowing refrigerant to escape to atmosphere from seals leaking. D. To avoid allowing air into the system if seals leak.

C. To avoid allowing refrigerant to escape to atmosphere from seals leaking.

What is the purpose of an SOP? A. To break down the amount of work to be done in a given time. B. To read after the job is done. C. To provide guidance and specific steps necessary to safely operate the system. D. To provide a standard way to perform the job faster.

C. To provide guidance and specific steps necessary to safely operate the system.

A slight leak in a fitting on a HCFC-22 system causes the halide torch flame to A. Turn purple. B. go out. C. Turn green. D. Turn red.

C. Turn green.

Superheated refrigerant can only be a __________ A. Solid. B. Liquid. C. Vapor. D. Combination of liquid and vapor.

C. Vapor.

Which of the answers below is an example of heat transfer by convection? A. The sun's ray hitting a roof. B. A rod that is heated on one end resulting in a temperature change at the other end. C. Warm air rising and cold air falling. D. Heat transferred to a pan setting on an electric hot plate.

C. Warm air rising and cold air falling.

Using the vapor pressure curve for ammonia, 70°F equals approximately what value? A. 38 psig B. 40 psig C. 70 psig D. 114 psig

D. 114 psig

What is the theoretical discharge temperature for ammonia at 93°F condensing and 0°F evaporating temperature? A. 312°F B. 255°F C. 318°F D. 242°F

D. 242°F

If specific heat for air is .24 BTU/lb./°F and the specific volume is 12.7 cu. ft./lb, how much heat energy must be removed to cool the air in a room that is 16' x 12' x 8' from 70°F to 40°F? A. 140,452 BTUs B. 1,536 BTUs C. 29 BTUs D. 870.8 BTUs

D. 870.8 BTUs

The reason for testing the application of a lockout device is to __________ A. Show your manager the LOTO procedure. B. Ensure that the multi-meter is working correctly. C. Conform to the OSHA regulations for electrical gear. D. Conform that the energy source has indeed been made safe.

D. Conform that the energy source has indeed been made safe.

Which is NOT a direct symptom of air in an ammonia system? A. Increased discharge temperature. B. Increased power consumption. C. Damage to the oil. D. Decreased evaporating temperature.

D. Decreased evaporating temperature.

Flash gas is __________ A. Only formed in ammonia refrigeration systems. B. Formed in a high pressure receiver. C. Formed in a condensor. D. Formed at the point of expansion.

D. Formed at the point of expansion.

Saturated conditions are found __________ A. Only in a condenser. B. Only in an evaporator. C. Only in the liquid lines. D. In both an evaporator and a condenser.

D. In both an evaporator and a condenser.

Sensible heat __________ A. Is measured using a pressure gauge. B. Is always between 32 and 212 degrees Fahrenheit. C. Is heat energy that causes a change of state but does not cause a change in temperature. D. Is heat energy that causes a change in temperature but does not cause a change of state.

D. Is heat energy that causes a change in temperature but does not cause a change of state.

Which of the following is NOT a true statement about heat of compression? A. It happens to all refrigerant vapors in mechanical refrigeration systems. B. It is the energy that is applied to the vapor by the compressor reducing the volume. C. It is one reason why a condenser must be sized larger than just the evaporator load. D. It improves the operating efficiency of most systems by improving the condensing rate.

D. It improves the operating efficiency of most systems by improving the condensing rate.

The condition of a boiling liquid is __________ A. Always hot. B. Superheated. C. Subcooled. D. Saturated.

D. Saturated.

During an arc flash event, what is the conductor? A. Hard rather than soft rubber shoe soles B. The disconnect handle C. The water in the hose that is too close D. The air

D. The air

Superheat is found at which points of a typical system? A. The compressor suction and the liquid line. B. The compressor suction and high pressure receiver inlet. C. The condenser outlet (CD) line. D. The compressor suction and compressor discharge line.

D. The compressor suction and compressor discharge line.

Temperature is a measure of __________ A. The latent heat of an object. B. Heat fusion that has been absorbed by an object. C. Heat of vaporization. D. The intensity of the heat energy in an object.

D. The intensity of the heat energy in an object.

When working on an ammonia refrigeration system, which of the following has the responsibility to use the proper PPE? A. As mandated by EPA regulations B. The owner of the facility C. The HR department D. The technician or operator

D. The technician or operator

What is the purpose of the refrigeration system? A. To freeze food B. To cool buildings C. To preserve food D. To maintain a temperature

D. To maintain a temperature

What is one reason discharge temperatures are lower on screw compressors than on reciprocating compressors? A. Uses glycol cooling to minimize discharge temperature. B. Uses water cooling to minimize discharge temperature. C. Uses air cooling to minimize discharge temperature. D. Uses lubricating oil through the compression chamber.

D. Uses lubricating oil through the compression chamber.

Saturated refrigerant can __________ A. Only be a liquid. B. Only be a vapor. C. Only be a combination of liquid and vapor. D. be a liquid, vapor or combination of the two.

D. be a liquid, vapor or combination of the two.

Which of the following refrigerants can be detected by its odor even in low concentrations? A. R-717 B. R-134a C. R-718 D. HCFC-22

A. R-717

-40°F is equal to __________ A. -40°C B. 40°C C. 0°C D. -32°R

A. -40°C

If the force acting on an area of 5 square inches is 150lb., what is the pressure on the area? A. 30 lb./in² B. 750 lb./in² C. 155 lb./in² D. 3750 lb./in²

A. 30 lb./in²

As an arc flash fault continues, the arc flash explosion expansion is estimated to be how large? A. 40,000 to 1 B. Relatively small compared to most explosions C. About the same size as a typical ammonia explosion D. 10 atmospheres

A. 40,000 to 1

MILK: 0.93 BTU/lb./°F A gallon of milk weighs 8 pounds. If it leaves the cow at 90°F and must be cooled to 35°F, how many BTUs must be removed in the cooling process? A. 409.2 BTU B. 40.9 BTU C. 440 BTU D. 51.15 BTU

A. 409.2 BTU

The pressure midway between 0 psia and 0 psig is __________ A. 7.35 psia. B. 7.35 psig. C. 7.35 in. Hg Vacuum. D. 0 in. Hg Vacuum.

A. 7.35 psia.

What can be caused by trapped liquid? A. A possible release B. Excess refrigerant flow C. The system pump down D. A safe condition for isolated components

A. A possible release

What is needed to get a fluid to flow? A. A pressure difference B. A temperature difference C. Superheat D. Flash gas

A. A pressure difference

Under the Clean Air Act and Montreal Protocol, A. As long as a technician does not perform work on portions of a system containing refrigerants, they do not need to be certified. B. As long as a technician is only adding refrigerant to a system, and not reclaiming any, it is not necessary to be certified. C. A technician must be certified to do any work, including electrical repairs, to a unit. D. Technicians working on ammonia systems must be certified by an outside agency.

A. As long as a technician does not perform work on portions of a system containing refrigerants, they do not need to be certified.

Operators must keep refrigeration systems operating safely and efficiently. Which of the following best describes the areas of required knowledge for this to be possible? A. Basic physical principles, interpretation of information from temperature and pressure gauges, basic operating principles. B. Basic physical principles, interpretation of information from temperature and pressure gauges, manufacturer of the equipment. C. Interpretation of information from temperature and pressure gauges, basic operating principles, company quality control policies and procedures. D. Interpretation of information from temperature and pressure gauges, manufacturer of the equipment, company quality control policies and procedures.

A. Basic physical principles, interpretation of information from temperature and pressure gauges, basic operating principles.

Which of the following is used to measure the quantity of heat energy? A. British Thermal Units (BTUs) or calories B. Pascals and Kilopascals C. Degrees Kelvin D. Degrees Celsius or Fahrenheit

A. British Thermal Units (BTUs) or calories

How can pumping capacity be increased by smaller reciprocating compressors vs. older and larger systems? A. By increasing RPM and the number of cylinders. B. By increasing motor horsepower. C. By enlarging suction valve diameter. D. By reducing RPM and the number of cylinders.

A. By increasing RPM and the number of cylinders

How does the refrigeration technician/operator know what the conditions are within a refrigeration system? A. By using his knowledge of system basic operating principles to evaluate temperature and pressure readings. B. By observing the alarm annunciator panel, if no alarms are displayed the system is operating efficiently and correctly. C. By keeping the discharge and suction pressures within specification the operator assures proper system operation. D. By observing product temperature, if the product is at temperature the system is operating properly.

A. By using his knowledge of system basic operating principles to evaluate temperature and pressure readings.

If a system using reciprocating compressors has the evaporator temperature decreased, what happens to the theoretical discharge temperature? (Assume constant condensing pressure) A. Discharge temperature rises. B. Discharge temperature is unaffected. C. Discharge temperature falls. D. Depends on the type of condenser.

A. Discharge temperature rises.

How does the refrigeration compressor maintain the temperature in the system evaporators? A. Drawing out vaporized refrigerant at a rate to maintain the desired evaporating pressure. B. Increasing pressure. C. By using liquid injection or thermo-siphon cooling. D. Compressors do not maintain evaporator temperatures.

A. Drawing out vaporized refrigerant at a rate to maintain desired evaporating pressure.

Specific heat __________ A. Is greater if the substance requires more heat energy to increase the temperature. B. Is less as the substance requires more heat energy to increase temperature. C. Is 1 BTU/lb./degree Fahrenheit for all substances. D. Is related to change of state, not temperature change of a substance.

A. Is greater if the substance requires more heat energy to increase the temperature.

Mechanical refrigeration is a series of steps that __________ A. Moves heat energy from a space or object to an area where it can do no harm. B. Adds cold to a space or object. C. Transforms heat energy into cold energy to reduce the temperature of the area to be cooled. D. utilizes the cooling effect of compressing a gas to reduce the temperature in a space or object.

A. Moves heat energy from a space or object to an area where it can do no harm.

Under the same operating conditions, which refrigerant listed below would operate with the lowest CFM per ton requirement? A. R-717 B. R-134a C. HCFC-22 D. R-507

A. R-717

What is the purpose of the refrigeration compressor? A. To draw vapor away from the evaporator at the same rate it is being generated and to raise the pressure of that vapor to a point where it can be condensed. B. To superheat the refrigerant gas that is drawn from the evaporator to ensure it is not condensed prior to entering the condenser. C. To move vaporized refrigerant from the high side to the low side at the same rate it is being generated to raise the pressure of that vapor to a point where it can be condensed. D. To provide hot gas to allow for more efficient hot gas defrost.

A. To draw vapor away from the evaporator at the same rate it is being generated and to raise the pressure of the vapor to a point where it can be condensed.


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