Refrigeration Flashcards

1
Q

What temperature is comfort cooling?

A

75 f

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2
Q

medium temperatue refrigeration

A

35 f

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3
Q

Walk in refrigerator usually operate in a range of ____°F to ____°F

A

35°F to 37°F

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4
Q

walk-in freezers normally run at _______°F and reach-in freezer operate at about 0°F

A
  • 10 °F
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5
Q

r134a Is a single chemical refrigerant, known as an ________, which boils and condenses at a single pressure and temperature.

A

Azeotrope

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6
Q

___________ are blends of different refrigerants.

A

zeotropes

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7
Q

EPA

A

Environmental Protection Agency

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8
Q

Warm air from the space is blown over the _________. Heat from the air is absorbed into the refrigerant as it boils within the ________ tubing.

E

A

Evaporator

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9
Q

it rejects heat

A

Condenser

latent eat is relesed as the vapor condenses into lidquid within the con

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10
Q

refrigerant temperature must be rised much higher. The ____ raises the temp by raising the pressure.

A

Comperssor

The compressor can raise the refrigerant
temperature by raising its pres

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11
Q

Reduces the liquid pressure by forcing it through a nozzle or small opening.

A

Metering device

Lowering the pressure of the refrigerant allows it to boil
at a lower t

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12
Q

What is considered the normal temperature of a walk-in refrigerator?

A

?38 °F - 40°F

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13
Q

at what temperature does the refrigerant condense?

A

?115 °F

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14
Q

R22 refrigerant at 49 psig boils at what temp?

A

?75 °F

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15
Q

What is considered the normal temp of a reach in freezer?

A

35? °F - 37°F?

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16
Q

how can the latent heat in a cold suction line be transfered to higher outdoor air temp?

A
17
Q

which refrigerant is used most in recently installed walk in refrigerations?

A

?

18
Q

why do zeotropic have temp glide?

A

?the component refrigerants boil off at different rates.

19
Q

which refrigerant is used mostly in recently installed reack in refrigerant?

?

A

?

20
Q

(TD)

A

Temperature Difference

21
Q

determining whether an evaporator has too much or too little refrigerant.

A

superheaat measurement

22
Q

the primary functionn of an evaporator is?

A

to absorb heat from the refrigerated space

23
Q

Secondary function of evaporator is to ?

A

to remove or maintain humidity in the space.

24
Q

evaporator temperature

A

refrigerant temperature inside the evaporator tubing.

25
Q

(p/t)

A

pressure / temperature

26
Q

td

A

temperature difference between the evaporator temperature and the temperature of the refrigerated space.

27
Q

delta t

A

as the difference between supply and returne air temperatures

28
Q

if a walk in cooler is running at 35 f box temperature, what should the evaporator temp be?

A

10 f lower than the box temp

29
Q

Heat always moves from a _________ surface to a _________ surface, a

A

warmer, cooler

30
Q

The warm air ________ and the
cooler air falls.

A

rises,