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Unit 36 Refrigeration Applied > Unit 36 Refrigeration Applied to Air Conditioning > Flashcards

Unit 36 Refrigeration Applied to Air Conditioning Flashcards

1
Q

Conduction

A

Form of heat transfer where heat energy is directly transferred between molecules through molecular collisions or direct contact.

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2
Q

Radiation

A

Energy that is radiated or transmitted in the form of rays or waves or particles.

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3
Q

Sensible Heat

A

Heat energy that brings about a change in temperature. Occurs in Conduction and Convection. lowers the air temperature.

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4
Q

Latent Heat

A

Heat energy absorbed or rejected when a substance changes state and there is no change In temperature. changes the water vapor in the air to condensate.

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5
Q

Convection

A

Heat transferred by the movement of fluids-liquids and gases

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6
Q

Evaporative Cooler

A

Device for cooling homes in dry climates that cools the incoming air by humidifying it.

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7
Q

The A coil

A

is used for upflow,downflow, & horizontal flow applications. it consists of two coils with their circuits side by side and spread apart by the bottom

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8
Q

The Slant coil

A

is a one piece coil mounted in the duct on an angle (usually 60 degrees ) or slant to give the coil more surface area.

The slant of the coil causes the condensate water to drain to the condensate pan located at the bottom of the slant.

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9
Q

The H coil

A

is normally applied to horizontal applications, although it can be adapted to vertical applications by using special drain pan configurations. the drain is normally at the bottom.

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10
Q

the solar load on a structure is the load resulting from the :

A

heat from the sun’s radiation

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11
Q

infiltrated air of the same dry-bulb temperature may vary from one part of the country to another because of the difference in

A

humidity

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12
Q

air blown into a structure through an evaporative cooler (swamp cooler) tends to ____ than the outside air.

A

be more humid

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13
Q

in a package air-conditioning system, the evaporator will normally be located

A

Outside the house

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14
Q

the fins of an evaporator coil are made of

A

aluminum

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15
Q

more than one evaporator coil circuit may be used when

A

there would be excessive refrigerant pressure drop

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16
Q

the cooling for modern reciprocating fully hermetic compressors used in air conditioning is controlled by or directly from

A

The suction gas

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17
Q

a compressor that has a stationary vane is the ____ compressor

A

Rotary

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18
Q

high efficiency condensers

A

have more surface area than standard condensers

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19
Q

two types of expansion devices used in residential air conditioning are the thermostatic expansion valve and the :

A

fixed-bore device

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20
Q

the thermostatic expansion unit (TXV)

A

does not allow the pressure to equalize during the off cycle unless specifically designed to do so

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21
Q

the air leaving the air handler in a typical air-conditioning system is approximately

A

55 degrees fahrenheit

22
Q

the supply air duct in an air conditioning system installed in an unconditioned space______(does or does not) need to be insulated

A

Dose

23
Q

two names for the interconnecting piping in a split air-conditioning system are

A

suction(cool gas) and liquid

24
Q

in the southwestern united states on a 90/f day, the condensing temperature for a standard air-conditioning system would be approximately

A

120/f …. 90 + 30=120

25
Q

a refrigerant blend replacing r-22 in new residential and commercial air-conditioning applications is

A

R-410A

26
Q

A refrigerant blend replacing R-22 that can be used in a retrofit application

A

R-407C

27
Q

by the year _____ R-22 can no longer be used in new air conditioning equipment

A

2010

28
Q

the total production phase out for R-22 will occur in

A

2020

29
Q

a dirty condenser coil can lead to

A

reduced efficiency, increased head pressure

30
Q

a home owner plans to build a house out in Las Vegas, Nevada, in the middle of the desert. It would be in his/her best interest to lower the “solar load “, to locate most of the windows on the ________and________ sides of the house

A

North & south

31
Q

Under what conditions would a package air-conditioning system need to be charged?

A

during compressor replacement, after the suction line is cracked.

32
Q

on a package air conditioning system , which refrigerant lines must be field installed ?

A

None

33
Q

on a split air conditioning system with a remote condenser/condensing unit which refrigerant lines must be field installed?

A

Liquid & suction

34
Q

the air temperature of the air “off” an evaporative cooler is

A

cooler than the entering air

35
Q

in reciprocating and scroll type motor-compressor assemblies , the motor is cooled by ______

A

suction gas returning to the compressor

36
Q

in ROTARY type motor-compressor assemblies, the motor is cooled by _______

A

discharge gas from the compressor

37
Q

The most popular material combination used in air conditioning evaporators and condensers is

A

copper-tube aluminum fin

38
Q

when exposed to salt air , the material combination used in air conditioning evaporators and condensers may be____

A

copper tube-copper fin

39
Q

when an “A” coil is used in a horizontal application , the coil is laid on its side and a special______ is required

A

drainpan

40
Q

slant coils for downflow application are designed with a coil slant of _______degrees

A

60 (degrees)

41
Q

A compressor that uses a stationary vane / rotating vane is the _________type

A

Rotary

42
Q

Three types of expansion devices are used in residential air conditioning systems. they are _______,_______, & _____.

A

TXV,Fixed bore,Orifice

43
Q

There are two types of Attic Ventilation

A

power and natural

44
Q

Three common coil evaporator designs used in air conditioning equipment ?

A

The A coil, The Slant coil, The H Coil

45
Q

A field technician installed two side air discharge condensing units next to each other so that the discharge air of unit “A” feeds into the condensing unit “B” . what is likely to happen?

A

Unit “A” will work fine while unit “ B” will not reject heat as well

46
Q

on a multi- directional air handler ( an air handler that can be mounted as a right flow, left flow, or up flow) what must the installing technician remember to do before connecting ?

A

install proper drip pan , make sure air handler is mounted in the correct direction

47
Q

if a high efficiency condensing unit is manufactured with a one-speed condenser fan motor,what is likely to happen if the system is operating during mild weather?

A

If the fan is high speed then the condensers would be too efficient in mild weather resulting in low head pressure, starving the expansion device and resulting in less capacity

48
Q

what is the major ADVANTAGE a top air discharge condensing unit has over a side air discharge condensing unit?

A

The hot air and noise are discharged from the top of the unit into the air…

49
Q

what is the major DIS-ADVANTAGE of a top air discharge condenser over a side air discharge condenser?

A

the fan and the motor are at the top of the equipment ,and rain,snow, and leaves can fall directly into the unit.

50
Q

Heat leaks into the structure by

A

Conduction, infiltration, and radiation

Unit 36 Refrigeration Applied (1 decks)

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