[Refrigeration Systems] Flashcards

1
Q

Instantaneous evaporation of liquid refrigerant in an evaporator

A

Flash gas

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2
Q

What may be closed to prevent toxic or dangerous vapors from entering the vessel?

A

Dampers

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3
Q

Carries the refrigerant vapor from the evaporator to the compressor

A

Suction line

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4
Q

Four variables that the design of a capillary tube depends on

A
  • Tube length
  • Inside diameter
  • Tightness of tube windings
  • Temperature of tubing
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5
Q

Two types of piston rings

A
  • Compression ring - upper ring

* Oil ring - lower ring designed to control the oil “flow” past the piston

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6
Q

What type of thermometer detects infrared rays produced by a substance?

A

Radiometer

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7
Q

Three types of compressors

A
  • Hermetic
  • Semi-hermetic
  • Open type (externally driven)
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8
Q

Amount of heat required to raise the temperature of one pound of water one degree Fahrenheit

A

BTU

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9
Q

Process in which a gas is compressed without losing heat to the surroundings

A

Adiabatic compression

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10
Q

Safety device that prevents liquid refrigerant from flowing into the suction line and compressor

A

Accumulator

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11
Q

Serves as a pressure plate in a cylinder, supporting and holding the valves and valve plate in position

A

Cylinder head

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12
Q

Connects to the lower end of the piston by means of a floating bearing in a Scotch yoke mechanism

A

Crankthrow (crankshaft pin)

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13
Q

1) Maintains proper flow of refrigerant; provides and controls refrigerant
2) What are the two types?

A

1) Refrigerant metering device

2) Thermostatic-controlled expansion valves and capillary tubes

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14
Q

Vapor formation in a capillary tube

A

Vapor lock

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15
Q

Leak-proof container that houses crankshaft

A

Crankcase

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16
Q

Back-and-forth action in a straight line

A

Reciprocating

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17
Q

Heat is a form of what?

A

Energy

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18
Q

SI metric unit of heat

A

Joule (J)

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19
Q

Connecting rods that are shorter than the master connecting rod

A

Articulated rods

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20
Q

Four components of refrigeration

A
  • Compressor
  • Condenser
  • Refrigerant control device
  • Evaporator
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21
Q

What is the most damaging condition of refrigeration operation?

A

Refrigerant slugging (allowing liquid refrigerant to enter the compressor)

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22
Q

What discharge air from the vessel to the atmosphere?

A

Exhaust system and fans (axial and centrifugal)

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23
Q

What measures the heat intensity or heat level of a substance?

(measures the speed of motion of the atom)

A

Temperature

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24
Q

What is happening when a fluid evaporates?

A

Heat is absorbed

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25
Q

Coils cooled by brine or any fluid which does not evaporate in the coil

A

Cooling coils

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26
Q

Contact device with a remote bulb mounted in the duct or plenum of an air handling unit to measure air temperature in such a way that it does not see radiant heat directly from the heater

A

Duct thermostats

27
Q

How is temperature measured?

A

Thermometer

28
Q

Part of refrigerator mechanism where liquid refrigerant boils or evaporates and absorbs heat

A

Evaporator

29
Q

Volume of space between piston and cylinder head at TDC

A

Clearance space

30
Q

Motor-driven device which removes the heat-laden vapor refrigerant from the evaporator

A

Compressor

31
Q

Expendable refrigerant usually used in an expendable refrigerant refrigeration system

A

Liquid nitrogen

32
Q

What is the moisture level?

A

Humidity

33
Q

What consists of duct heaters, unit heaters, and convection heaters?

A

Heating system

34
Q

What maintains correct operating temperature by controlling the motor electrical circuit?

A

Thermostat

35
Q

What are the major supply systems feeding air into the vessel?

A

Air intake trunks (ducts)

36
Q

What are the major components in an air conditioning cooling cycle?

A
  • Cooling coil
  • Compressor
  • Condenser
  • Expansion valve (or capillary tube assembly)
37
Q

Temperature of the air surrounding a motor, control mechanism, or any other device

A

Ambient temperature

38
Q

What provides local filtering and reheating or cooling of air?

A

Recirculating (return air) system

39
Q

Mechanical refrigeration cycle

A
  • Closed system
  • Continuously circulating
  • Condensation
  • Evaporation
40
Q

Temperature control device that is mounted on the wall in the area which it serves

A

Room thermostats

41
Q

What is the SI unit of temperature?

A

Kelvin (K)

42
Q

When does the HVAC process begin?

A

As weather air enters the HVAC supply intakes

43
Q

Pressure of a vapor in contact with a liquid

A

Vapor pressure

44
Q

Instrument used when accurate readings at various temperatures are needed

A

Thermometer-pyrometer

Pyrometer means “high temperature

45
Q

Three safety considerations

A
  • Safety of operator
  • Safety of equipment
  • Safety of content
46
Q

What is the American conventional unit of temperature?

A

Fahrenheit

47
Q

What move the air through the supply ducts to ventilate compartments and to heat or cool the air?

A

Supply fans

48
Q

Amount of heat required to raise the temperature of one gram of water one degree Celsius

A

Calorie

49
Q

What is often done to the connections of a capillary tube?

A

Brazed

50
Q

What removes air from the galley along with all cooking smoke and odors?

A

Galley exhaust fan

51
Q

Unit which equals 100,000 BTU

A

Therm

52
Q

Sequence of events

A
  • Liquid line
  • Expansion valve
  • Evaporator
  • Suction line
  • Compressor
  • Discharge line
  • Condenser
53
Q

What does the operation of a mechanical refrigerator rely on?

A

Heat absorption property of a fluid passing from the liquid to the vapor state

54
Q

Shaft section which is larger and has a different center than the shaft

A

Eccentric

55
Q

Type of refrigerant control that consists of a length of seamless tubing with a small and accurate inside diameter

A

Capillary tube

56
Q

What is the thermal energy of the atom multiplied by the number of atoms (mass)?

A

Heat

57
Q

What does a substance state consist of?

A
  • Pressure
  • Heat content
  • Temperature
58
Q

What is the American conventional unit of heat?

A

British Thermal Unit (BTU)

59
Q

Temperature where molecular motion stops (all heat is removed)

*lowest temperature possible

A

Absolute zero

60
Q

What happens when a gas is compressed?

A

Temperature rises (heat of compression)

61
Q

1) Insulated cabinet equipped with a tray or tank at the top for holding blocks or pieces of ice
2) What is the advantage?

A

1) Typical ice refrigerator

2) Maintaining the interior of the cabinet at a fairly high humidity

62
Q

Keeps moisture, dirt, metal, and chips from entering the refrigerant flow control

A

Liquid line filter-drier

63
Q

How does natural air enter a room?

A

Door louvres