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Evap, Cond, MD, Receivers > Powerpoint: Receivers/Evaporators > Flashcards

Powerpoint: Receivers/Evaporators Flashcards

1
Q

Filling receivers with liquid is ______

A

illegal

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2
Q

A receiver is essentially a _______ tank for refrigerant

A

storage

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3
Q

The receiver is a _____ side component

A

high

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4
Q

The Receiver inlet is from the _________ and the outlet goes to the ______________

A

condenser, metering device

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5
Q

Refrigerant receiver types;

Full size receiver: holds _______ system charge

A

holds entire system charge

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6
Q

Refrigerant receiver types;

Oversized receiver: holds ______ system charge (condenser flooding)

A

excess

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7
Q

Refrigerant receiver types;

Partial receiver: holds a ______ of the system charge and the rest in condenser (not in canada)

A

portion

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8
Q

What are the inlet and outlet valves called in a full size receiver?

A

Inlet - Queen valve

Outlet valve quill- King valve

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9
Q

Inlet and Outlet valves in a partial receiver?

A

Inlet - no valve

Outlet valve quill - King

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10
Q

Receiver capacity as required by B-52:

  1. Must hold the entire refrigerant charge and only occupy ___% of its volume at ___F
  2. If refrigerant side head pressure capacity control is used the receiver must be oversized by ___%
A
  1. 90%, 90F

2. 50%

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11
Q

A cooling tower is a device for cooling water on a __________ system

A

recirculating

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12
Q

Cooling towers have no ________

A

refrigerant

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13
Q

Cooling towers use water to ______ heat from the water

A

reject

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14
Q

In a cooling tower, water is pushed to the ____ of the tower from the water cooled condenser and heat is rejected and _______ out the top

A

top

rejected and removed out of the top

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15
Q

Cooling tower low ambient controls;

  1. _______ valve
  2. diverting _____
  3. fan ______ ______
A
  1. mixing valve
  2. diverting valve
  3. fan speed control
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16
Q

Evaporators _______ heat into the refrigeration system

A

absorb

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17
Q

Evaporators absorb heat by maintaining the evaporator at a temperature ______ than the medium to be cooled

A

lower

18
Q

Evaporators remove both ______ heat and _______ heat from the medium to be cooled

A

latent heat and sensible heat

19
Q

Evaporator types:

  1. Dry (DX): Liquid/Vapour mix to start and a ____ at the exit
  2. Flooded:
    - _____ level of liq ref (used on direct or indirect systems)
    - Ref charge of flooded evap is _____than a DX evap
    - Used for ______ systems (ie. ice rinks)
A
  1. gas

2. Constant, larger, larger

20
Q

Construction of Evap:

  1. Bare pipe
  2. Finned Tube: fins increase surface area and attach to pipe to increase __________
  3. Plate: (may use eutectic solution) semi trucks and______ low freezers
  4. Shell and tube: flooded or dry indirect systems seen in chillers
A
  1. heat exchange

3. ultra low

21
Q

Finned tube type: ____ velocity

temperature range is ___F and above

A

28

22
Q

Unit cooler temperature range is ____F and above (most common)

A

-40F and above

23
Q

Product cooler temp range is ____F and above and is the largest evaporator

A

-40F and above

24
Q
  • Fin spacing and temperature application:
    1. Frosting application- product coil must be below ___F (approx __fin/inch)
      1. Defrost method must have an external heat source to raise temp above ____F
      2. When in defrost you must shut off the evap ____
      3. External heat sources could be hot ____, ______, or hot _____
A
  1. 32F, 4fin/inch
  2. 32F
  3. fan
  4. hot gas, electric, hot water
25
Q
  • Fin spacing and temperature application:
    1. Defrosting application- coil must be below ___F and product above ___F (approx __fin/inch)
      1. Defrost method is ___/_______
      2. keep the evaporator fan ________ during defrost
A
  1. 32F, 32F, 6fin/inch
  2. air / positive
  3. running
26
Q
  • Fin spacing and temperature application:
    1. Non-frosting application -coil above ___F (approx __fin/inch)
      1. The defrost method is ____ required
      2. Improved fin designs reduces stratification by causing _______
A
  1. 32F, 8fins/inch
  2. not required
  3. turbulence
27
Q

DEFROSTING METHODS;

  1. Electric (most common): lower first cost higher operating cost, ____ and _____ released into the space
  2. Hot gas (most efficient): ____ defrost with minimal _____ temperature rise

Hot water (not common): ____F water is sprayed onto a coil at 3GPM, has ____ defrost but requires more maintenance

A
  1. heat and moisture
  2. fast, minimal space temperature rise
  3. 50F, fast defrost
28
Q

What are the three methods of stopping the defrost cycle known as defrost termination?

A
  1. Time
  2. Temperature
  3. Pressure
29
Q

Defrost Termination:

Defrost timers with a solenoid can terminate defrost by ____ and _______

A

time and temperature

30
Q

Defrost Termination

Defrost timers with a solenoid are for ___ temp

A

low

31
Q

Defrost Termination:

Defrost timers without a solenoid are for ____ temperature

A

medium

32
Q

Defrost Termination:

Defrost timers without a solenoid can only terminate defrost by ____

A

time

33
Q

Coil temperature difference (TD):

this determines ______ humidity level

A

space

34
Q

Coil Temperature difference:

Evaporator coil TD= Air entering Evap - ____

A

SST

35
Q

Normal coil TD’s and Relative Humidity:

  • 8 to 10F =
  • 10 to 12F =
  • 12 to 14F =
  • 14 to 18F =
A

8 to 10 = 90% +

10 to 12 = 85% to 90%

12 to 14F = 80 to 85%

14 to 18F = 70 to 80%

36
Q

Purpose of refrigerant distributor:

  1. Has multiple _____/ multi- circuit ____
  2. Eliminates ______ drop thru long coils by feeding ref. thru multiple circuits within the coil
  3. provides equal _______ of liquid and vapour to each coil circuit
A
  1. branches/multi circuit coils
  2. pressure drop
  3. distribution
37
Q

Capacity control for evaporators:

  1. Coil splitting methods; _____/row split (stacked), _____/face split (in line)
A
  1. vertical, horizontal
38
Q

Shell and tube evaporator types;

2

A

Dry (DX) and Flooded

39
Q

Shell and Tube Evaporators:

  1. Dry- location of primary ref is on the ____ side and secondary ref on the ____ side
  2. Purpose of baffled (full or half) is to provide maximum exposure of secondary ________ to primary refrigerant circuits
A
  1. Tube, Shell

2. refrigerant

40
Q

Shell and Tube Evaporators:

  1. Flooded- location of primary refrigerant ____ side and secondary ref on ____ side
  2. Tube bundle on ______ of shell
  3. Purpose of ________ is to prevent liquid ref from returning to the compressor
  4. Surge drum (accumulator) provides for removal of _____ gas so it does not waste space in the cooler
A
  1. shell side, tube side
  2. bottom
  3. eliminators
  4. flash gas
41
Q

Evaporator Capacity or Efficiency control:

  1. _____ water flow at all times
  2. Temperatures: low temp __F TD (secondary refrigerant entering/leaving)
  3. High temp application ___ to ___F TD (secondary refrigerant entering/leaving)
  4. Air Cond. chilled water supply at ___ to ___F
  5. Air conditioning supply air temp ____F
  6. Secondary ref controlled by ______ conditions
A
  1. constant
  2. 2F
  3. 10 to 15F
  4. 40 to 45F
  5. 55F
  6. entering

Evap, Cond, MD, Receivers (16 decks)

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