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RETA Industrial Refrigeration Book 1 Exam
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Which one of the following statements is correct? (pg. 7-9) A) Oil is heavier than liquid ammonia B) Oil is lighter than liquid ammonia C) Oil and liquid ammonia mix in proportion D) Oil separators always removed 100% of the oil from ammonia ---------CORRECT ANSWER-----------------A) Oil is heavier than liquid ammonia What should be done if liquid refrigerant appears while draining oil? (pg. 7-11) A) Notify the plant engineer B) Open the oil drain valve C) Close the oil drain valve D) Open the valve in the still vent line ---------CORRECT ANSWER-----------------C) Close the oil drain valve Sophisticated oil recovery systems are sometimes required for halocarbon refrigerants because oil and halocarbon refrigerants are? (pg. 7-17) A) Complementary
B) Soluble and quite miscible C) Different D) Water soluble ---------CORRECT ANSWER-----------------B) Soluble and quite miscible Most oil separators for screw compressors are multi-stage separator. The number of steps is? (pg. 7-19) A) 1 B) 4 C) 5 D) 10 ---------CORRECT ANSWER-----------------B) 4 (impingement, change of direction, gravity separation, coalescing) Which of the following is not a use for oil? (pg. 7-2) A) Cooling B) Lubricating C) Sealing D) To improve heat transfer in coils ---------CORRECT ANSWER-----------------D) To improve heat transfer in coils A thermosyphon oil cooling system? (pg. 7-21) A) Use an air-cooled heat exchanger to cool the oil
What indicates that most of the oil has been drained from a collection point in an ammonia system? (pg. 7-13) A) The spring loaded 1/4 turn ball valve closes automatically B) Ammonia, liquid or vapor, appears at the oil outlet C) Frost disappears from the drainpipe D) The oil becomes less foamy ---------CORRECT ANSWER-----------------B) Ammonia, liquid or vapor, appears at the oil outlet Sophisticated oil recovery systems are sometimes required for halocarbon refrigerants because oil is? (pg. 7-17) A) Lighter than the refrigerant B) Immiscible with the refrigerant C) Found at the bottom of the receiver D) Halocarbon systems do not require sophisticated oil recovery systems --------- CORRECT ANSWER-----------------A) Lighter than the refrigerant In a refrigeration system, oil is required for? (pg. 7-2) A) Lubrication only B) Lubrication and to purify the refrigerant C) Lubrication and cooling only D) Lubrication, cooling, sealing, and cleaning ---------CORRECT ANSWER--------------- --D) Lubrication, cooling, sealing, and cleaning
Proper oil management for a refrigeration system requires that? (pg. 7-18) A) It is only necessary to log oil added to a system B) It is only necessary to log oil removed from a system C) A log should record all oil added to and removed from a system D) It is unnecessary to log oil added to or removed from a refrigeration system ---- -----CORRECT ANSWER-----------------C) A log should record all oil added to and removed from a system An HCFC-22 liquid line is operating at 85°F and 185 PSIG. What is the condition of the refrigerant in the line? (pg. 4-17) A) Saturated vapor B) Saturated liquid C) 11°F superheated liquid D) 11°F subcooled liquid ---------CORRECT ANSWER-----------------D) 11°F subcooled liquid An ammonia compressor is operating with - 30°F suction temperature and a suction pressure of 8.7 inches of vacuum. What is the condition of the suction vapor? (pg. 4-4) A) 10°F superheated B) - 10°F subcooled C) Saturated D) 15°F superheated ---------CORRECT ANSWER-----------------A) 10°F superheated
If a cylinder of HCFC-22 containing a mixture of liquid and vapor is heated from 70°F to 165°F, what would be indicated? (pg. 4-19) A) Excessive and dangerous pressure B) A superheated vapor C) The cylinder is ready to use to charge a system D) Nothing, this is a normal operating pressure for HCFC- 22 ---------CORRECT ANSWER-----------------A) Excessive and dangerous pressure At 70°F? (pg. 4-9/16) A) HCFC-22 is lighter than ammonia B) Ammonia is lighter than HCFC- 22 C) Ammonia and HCFC-22 weight the same D) Ammonia and HCFC-22 both become superheated vapor ---------CORRECT ANSWER-----------------A) HCFC-22 is lighter than ammonia An ammonia suction line has been calculated to have a volume of 7 cubic feet. How many pounds of saturated ammonia vapor at - 30°F would this suction line contain? (pg. 4-5) A) 0.37 lbs. B) 29.9 lbs. C) 30.1 lbs. D) 36.9 lbs. ---------CORRECT ANSWER-----------------A) 0.37 lbs.
(vapor density at - 30°F is 0.0526 lbs./cubic foot) (0.0526 x 7 = 0.37 lbs.) How many cubic feet of 30°F saturated ammonia vapor would result from vaporizing 65 pounds of saturated ammonia at 30°F? (pg. 4-7) A) 314 cubic feet B) 1.63 cubic feet C) 323 cubic feet D) 16.3 cubic feet ---------CORRECT ANSWER-----------------A) 314 cubic feet (specific vapor at 30°F is 4.8360 x 65 lbs. = 314 cubic feet) An HCFC-22 liquid line has a volume of 0.15 cubic feet. How many pounds of saturated HCFC-22 liquid at 105°F will the line hold? (pg. 4-17) A) 18.55 lbs. B) 12.13 lbs. C) 10.57 lbs. D) 0.63 lbs. ---------CORRECT ANSWER-----------------C) 10.57 lbs. (liquid density at 105°F is 70.47 lbs./cubic foot) (70.47 lbs./cubic foot x 0.15 cubic feet = 10.57 lbs.) An HCFC-22 compressor is operating with a suction pressure of 30 PSIG. The suction temperature is 12°F, what is indicated? (pg. 4-15)
A) 96°F
B) 102°F
C) 99°F
D) 108°F ---------CORRECT ANSWER-----------------D) 108°F
193.76 PSIA is equal to? (pg. 4-3) A) 179.06 PSIG B) 207.46 PSIG C) 192.76 PSIG D) 199.04 PSIG ---------CORRECT ANSWER-----------------A) 179.06 PSIG (PSIA = PSIG + 14.7) Saturated liquid ammonia at 70°F weights? (pg. 4-9) A) 75.47 pounds per cubic foot B) 0.4315 pounds per cubic foot C) 38.04 pounds per cubic foot D) 2.4769 pounds per cubic foot ---------CORRECT ANSWER-----------------C) 38. pounds per cubic foot 250 pounds of saturated liquid ammonia at 85°F occupies? (pg. 4-9) A) 67.2 cubic feet B) 109 cubic feet
C) 6.7 cubic feet D) 450 cubic feet ---------CORRECT ANSWER-----------------C) 6.7 cubic feet (250 lbs. / 37.25 lbs. per cubic foot = 6.7 cubic feet) What is the purpose of the refrigeration compressor? (pg. 5-2) 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 insure 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 and 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 ---------CORRECT ANSWER-----------------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 How does the refrigeration compressor maintain the temperature in the system evaporators? (pg. 5-2) A) Drawing out vaporized refrigerant at a rate to maintain the desired evaporator pressure B) Increasing pressure C) By using liquid injection or thermosiphon cooling D) Compressors do not maintain evaporator temperatures ---------CORRECT ANSWER-----------------A) Drawing out vaporized refrigerant at a rate to maintain the desired evaporator pressure
As defined in Chapter one of this text, the primary purpose of a refrigeration system it to? (pg. 1-3) A) To freeze food B) To cool buildings C) To preserve food D) To maintain a temperature ---------CORRECT ANSWER-----------------D) To maintain a temperature 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? (pg. 1-4) 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 ---------CORRECT ANSWER-----------------A) Basic physical principles, interpretation of information from temperature and pressure gauges, basic operating principles Mechanical refrigeration is a series of steps that? (pg. 1-2)
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 ---------CORRECT ANSWER-----------------A) Moves heat energy from a space or object to an area where it can do no harm Heat energy always flows? (pg. 1-23) A) From a substance with more heat energy [measured in BTUs] to a substance with less heat energy [ measured in BTUs] 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 ---------CORRECT ANSWER-----------------C) From an object at a higher temperature to an object at a lower temperature Sensible heat? (pg. 1 - 22) A) Is measured using a pressure gauge B) Is always between 32°F and 212°F 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 ---------CORRECT ANSWER-----------------D) Is heat energy that causes a change in temperature but does not cause a change of state
C) By keeping the discharge and suction pressures within specification the operator assures proper system operationg D) By observing product temperature, if the product is at temperature the system is operating properly ---------CORRECT ANSWER-----------------A) By using his knowledge of system basic operating principles to evaluate temperature and pressure readings How is cooling accomplished by a mechanical refrigeration system? (pg. 1-2) A) By just pumping ice water through a space B) By just adding cold air C) By removing heat energy from an object or area D) By increasing the molecular vibration of an object ---------CORRECT ANSWER----- ------------C) By removing heat energy from an object or area Which of the following is used to measure the quantity of heat energy? (pg. 1-21) A) British Thermal Units (BTUs) or Calories B) Pascals and Kilopascals C) Degrees Kelvin D) Degrees Celsius or Fahrenheit ---------CORRECT ANSWER-----------------A) British Thermal Units (BTUs) or Calories Which of the following are used in heat calculations? (pg. 1- 40 A) Mass, sensible heat, temperature, specific heat
B) Mass, latent heat, temperature, specific heat C) Mass, sensible heat, heat of cooling, change of state D) Mass, latent heat, temperature, heat of refrigeration ---------CORRECT ANSWER-----------------B) Mass, latent heat, temperature, specific heat Latent heat of vaporization? (pg. 1-22) 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 ---------CORRECT ANSWER-----------------C) Is the heat energy required to cause a liquid to become a vapor Pressure is a measure of? (pg. 1-11) 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 ---------CORRECT ANSWER-----------------C) The relationship of a force being applied over a given area The relationship between temperature difference and heat flow is? (pg. 1-23) A) There is no relationship between temperature and heat flow B) The greater the temperature difference, the slower heat flows
B) 750 lb/in C) 155 lb/in D) 3750 lb/in2 ---------CORRECT ANSWER-----------------A) 30 lb/in Using the vapor pressure curve for ammonia, 70°F equals approximately? (pg. 1-
A) 38 PSIG B) 40 PSIG C) 70 PSIG D) 114 PSIG ---------CORRECT ANSWER-----------------D) 114 psig Thirty-two PSIA equals? (pg. 1-15) A) 46.7 PSIG B) 17.3 PSIG C) 3.2 in. Hg D) 760 mm Hg ---------CORRECT ANSWER-----------------B) 17.3 psig The pressure midway between 0 PSIA and 0 PSIG is? (pg. 1-17) A) 7.35 PSIA B) 7.35 PSIG C) 7.35 in. Hg D) 0 in. Hg ---------CORRECT ANSWER-----------------A) 7.35 PSIA
Which of the answers below is an example of heat transfer by conduction? (pg. 1-
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 standing upwind ---------CORRECT ANSWER------ -----------B) A rod heated on one end becoming warm at the other end Which answer below represents the two most common forms of heat transfer in refrigeration? (pg. 1-36) A) Conduction and radiation B) Conduction and convection C) Convection and radiation D) Conduction and sensible heat ---------CORRECT ANSWER-----------------B) Conduction and convection If specific heat for air is 0.24 BTU/lb/°F and the specific volume is 12.7 cubic feet/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? (pg. 1-40) A) 121 BTUs B) 1536 BTUs C) 29 BTUs
