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Gas A Level 2 > Block 2 - Gas-Fired Refrigeration Equipment Self Assessment > Flashcards

Block 2 - Gas-Fired Refrigeration Equipment Self Assessment Flashcards

1
Q

Which formula calculates the energy required to absorb or liberate heat without a phase change?

A

Sensible heat formula

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2
Q

What is the odor threshold of ammonia?

A

2 ppm

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3
Q

What is latent heat associated with?

A

Phase changes in a substance

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4
Q

Why is a formal risk assessment important for ammonia exposure control?

A

To identify affected workers and determine the extent of exposure

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5
Q

What is the primary advantage of lithium bromide systems?

A

They are nontoxic and safer to use.

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6
Q

What is the typical cooling limit of lithium bromide systems?

A

Around 41°F (5°C)

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7
Q

What should exposure control plans include?

A

Procedures for reducing exposure risks

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7
Q

What defines a “strong solution” in a lithium bromide/water system?

A

High lithium bromide concentration with no water

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8
Q

At what pressure range does the ammonia system typically operate?

A

200-230 Psig

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9
Q

Which substance in a lithium bromide system is highly corrosive to ferrous metals?

A

Lithium bromide

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10
Q

What substance is used as the absorbent in an ammonia/water system?

A

Water

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11
Q

What is the primary safety advantage of lithium bromide systems?

A

Non-flammable and nonreactive under most circumstances

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12
Q

Which refrigerant is associated with risks such as toxicity, flammability, and asphyxiation?

A

Ammonia

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13
Q

What is a potential hazard of ammonia exposure to workers?

A

Severe eye irritation and burns

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14
Q

What does an absorption refrigeration system use to create a cooling effect?

A

Heat, refrigerant, and adsorbent

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15
Q

Why is ammonia considered flammable and explosive?

A

It has an explosive range between 15% and 28% in air.

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16
Q

In which type of facility is an ammonia/water absorption system commonly found?

A

Ice arenas

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17
Q

What is required in an effective program for ammonia use and storage?

A

1) Regular inspections and a WHMIS program

2) Written safe work procedures

3) Emergency response plans and training

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18
Q

At what concentration is ammonia considered immediately dangerous to life and health?

A

300 ppm

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19
Q

What type of heat causes a change in temperature without a change in state?

A

Sensible heat

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20
Q

What is the approximate temperature of the chilled water as it exits the evaporator?

A

7°C (45°F)

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21
Q

Which substance acts as the absorber in a lithium bromide/water system?

A

Lithium bromide

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22
Q

Which energy sources can be used for the generator in an absorption system?

A

Natural gas, propane, or steam

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23
Q

What is the purpose of cooling tower water in a lithium bromide system?

A

Condense vapor particles and remove heat from the system

24
Q

What creates the vacuum condition in the absorber chamber of a lithium bromide/water system?

A

Strong attraction between water vapor and lithium bromide

25
Q

What causes the boiling point of water to change in an absorption system?

A

Absorption by lithium bromide

26
Q

Which of the following best describes the weak solution in a lithium bromide system?

A

Variations in system pressure

27
Q

At what pressure does water boil at approximately 4.5°C in a lithium bromide absorption system?

A

0.84 kPa

28
Q

What does the term “flash” mean in the context of the evaporator?

A

Sudden evaporation of water at low pressure

29
Q

What is the term for lithium bromide saturated with water?

A

Weak solution

30
Q

What is the role of the heat exchanger in a lithium bromide system?

A

Improve system efficiency by preheating the solution

31
Q

What is the primary purpose of the evaporator in both ammonia and lithium bromide systems?

A

Remove heat from the refrigerated space

32
Q

What is the primary refrigerant used in an ammonia/water absorption system?

A

Ammonia

33
Q

What is the primary function of the generator in an ammonia absorption refrigerator?

A

Separate ammonia from the water solution

34
Q

Which component removes heat from the ammonia vapor, causing it to condense into a liquid?

A

Condenser

35
Q

In the evaporator, what causes the tubes to become cold?

A

Evaporation of ammonia in a hydrogen atmosphere

36
Q

What is the role of the absorber in an ammonia/water absorption system?

A

Attract and absorb ammonia from the evaporator

37
Q

What happens to water vapor in the condenser of a lithium bromide system?

A

It condenses into liquid

38
Q

Why is lithium bromide used in absorption chillers?

A

It can easily separate from water when heated

39
Q

What happens to lithium bromide in the generator?

A

It remains as a concentrated liquid at the base

40
Q

Why does LG recommend a yearly maintenance contract?

A

To ensure stable operation through scheduled upkeep

41
Q

What is the recommended solution for fouling on heat exchanger surfaces?

A

Perform a thorough cleaning

42
Q

What should be done if refrigerant levels are low?

A

Refill and check for leaks

43
Q

How often should safety devices like pressure relief valves be checked?

A

Annually

44
Q

What is the primary purpose of annual maintenance on industrial direct-fired refrigeration chiller equipment?

A

Detect potential issues early

45
Q

What is the key indicator of improper combustion during air-fuel ratio checks?

A

Excessive CO levels

46
Q

Which of the following requires a separate maintenance contract?

A

Cleaning heat transfer tubes

47
Q

According to CARRIER, what should be done if multiple systems share the same exhaust stack?

A

Prevent backflow of exhaust gases

48
Q

What is the first step in the maintenance shutdown procedure?

A

Disconnect power sources

49
Q

What tool is recommended for cleaning condenser fins?

A

Brush-tipped vacuum

50
Q

How often should the burner main body components be checked?

A

Annually

51
Q

How frequently should major inspections for safety devices and adjustments be performed according to LG?

A

Yearly

52
Q

Why is it important to calibrate temperature and pressure sensors?

A

To maintain accurate system control

53
Q

Which maintenance task prevents heat loss and ensures energy efficiency?

A

Repairing damaged insulation

54
Q

What is the first step in troubleshooting a heat input issue?

A

Verify fuel supply

55
Q

What issue does vent blockage most commonly cause?

A

Incomplete combustion

56
Q

Which safety device ensures proper draft in a venting system?

A

Draft regulator

57
Q

Which component must be inspected for wear, corrosion, or damage during combustion system maintenance?

A

Burner assembly

58
Q

What is the purpose of a condensate drain in a venting system?

A

Handle moisture from high-efficiency systems

Gas A Level 2 (22 decks)

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