[ILM] 102A Flashcards

1
Q

absolute presssure

A

A system of pressure measurement with a starting point in a perfect vacuum

0 psig = 14.7 psia

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2
Q

absolute temperature

A

0R == -460F

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3
Q

adiabatic compression

A

The compression of refrigerant gas without removing or adding heat content

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4
Q

ambient temperature

A

The average temp of the media that surrounds a point

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5
Q

BTU (British Thermal Unit)

A

the amount of heat required to raise the temp of 1lb of water by 1F

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6
Q

enthalpy

A

The heat in 1 lb or kg of a substance from a zero-base point and at -40F

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7
Q

entropy

A

A measurement of energy transfer where the energy is moved but not used to do work

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8
Q

head, static pressure

A

Fluid pressure based on the height of a column of fluid

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9
Q

IDLH

A

Immediately Dangerous to Life or Health

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10
Q

laminar flow

A

The smooth undisturbed flow of a fluid within a duct or pipe

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11
Q

turbulent flow

A

The chaotic flow of a fluid within a duct or pipe

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12
Q

latent heat

A

Heat gained or lost with no temperature change

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13
Q

sublimation

A

a change of state from a solid directly to a vapour without having a liquid state (μŠΉν™”)

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14
Q

superheating

A

adding sensible heat to a vapour at its evaporation pressure

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15
Q

subcooling

A

removing heat from a liquid at its condensation pressure

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16
Q

desuperheating

A

sensible heat is removed from a vapour or gas while it remains at its saturation or boiling pressure

17
Q

Threshold limit value (TLV)

A

The refrigerant concentration in air for a normal 8 hr workday and a 40 hr workweek to which nearly all workers may be repeatedly exposed, day-after-day, without adverse effect

18
Q

1 ton of refrigeration ==

A

288,000 Btu/24hrs
12,000 Btu/hr
200 Btu/min

19
Q

Sensible heat

A

heat we can sense by touch

20
Q

Specific heat

A

the amount of heat required to change 1lb of a substance by 1F

21
Q

Heat is

A

energy in the form of molecular motion

22
Q

subcooling types

A
  1. an increase in the subcooling of liquid refrigerant results in a decrease of sensible heat in the refrigerant
  2. a decrease in sensible heat results in a decrease in the amount of heat contained by the refrigerant
  3. a decrease in heat results in an increased capacity in the cooling section
23
Q

The greater the temp difference between two objects,

A

the faster heat transfers

24
Q

Conduction

A

solid

25
Q

Convection

A

liquid or gas

26
Q

Radiation

A

purely gas

27
Q

Thermodynamics

A

study of changing heat energy into mechanical energy and mechanical energy into heat energy

28
Q

The first law of thermodynamics states

A

energy cannot be created or destroyed

29
Q

The second law of thermodynamics states

A

heat energy moves from a zone of high heat to a zone of low heat

high heat -> low heat

30
Q

liquid water (specific heat value)
ice (specific heat value)
steam (specific heat value)

A

1.00 btu/lb/F
0.5
0.46

31
Q

Sensible heat

A

a gain or loss of heat that is indicated by a rise or fall in temp

32
Q

Latent heat

A

a gain or loss of heat that does not register a temp change

33
Q

Total heat

A

the sum of latent heat and sensible heat

34
Q

Q =

A

m x c x T

Q = Quantity of Heat
m = mass
c = specific heat
T = temperature difference

35
Q

Temperature

A

the average amount of molecular motion in a substance