Refrigeration Fundamentals. Part 1. Heat and Heat Transfer

Сентябрь 14, 2022

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Refrigeration Fundamentals. Part 1. Heat and Heat Transfer

Содержание

2. Sect. 1 What is Refrigeration?
3. Sect. 1 DEFINITION ‘Refrigeration’… …is the transfer of heat from a place where it is ‘not
4. Sect. 1 HEAT REMOVAL If heat is removed from inside the container ‘faster’ than it enters...
5. Sect. 1 WHAT IS HEAT? A Form of Energy It Exists ‘Everywhere’ It Exists at ‘All
6. Sect. 1 WHAT ARE REEFERS? Machines that ‘Move Heat’
7. Sect. 1 ‘HOW’ DOES HEAT MOVE? Warmer ⇒ Colder - ALWAYS!!!!!!! Heat Heat Heat ‘Faster’ with
8. Sect. 1 ‘HOW’ DOES IT MOVE? Heat can move three (3) ways…. 1. Conduction 2. Convection
9. Sect. 1 CONDUCTION Heat moves through Solids & Liquids
10. Sect. 1 CONDUCTION Heat will move Between Solids and / or Fluids in direct contact with
11. Sect. 1 CONDUCTION
12. Sect. 1 Any other Examples of Conduction?
13. Sect. 1 CONVECTION Definition - Heat transfers via the circulation (movement) of a fluid. i.e….. Air
14. Sect. 1 ‘NATURAL’ CONVECTION Warm Air Rises Cool Air Falls Heater
15. Sect. 1 ‘NATURAL’ CONVECTION
16. Sect. 1 ‘FORCED’ CONVECTION
17. Sect. 1 ‘FORCED’ CONVECTION
18. Sect. 1 Any other Examples of Convection?
19. Sect. 1 RADIATION Moves in Straight Lines… like light Does not heat the air it passes
20. Sect. 1 RADIATION
21. Sect. 1 RADIATION
22. Sect. 1 Any other Examples of Radiation?
23. Sect. 1 HEAT TRANSFER SYSTEMS Usually combine ‘Conduction’ AND ‘Convection’ to move heat. i.e….
24. Sect. 1 TERMS TO REMEMBER Refrigeration Heat Box Conduction Convection Radiation
25. Sect. 1 HOW IS HEAT ‘MEASURED’? Four (4) Ways…. Temperature Sensible Heat British Thermal Unit (BTU)
26. Sect. 1 TEMPERATURE Is the Level or Intensity of heat energy Is measured in degrees Fahrenheit
27. Sect. 1 TEMPERATURE The temperature inside the controlled space (container) is called…. Box Temperature AMBIENT AMBIENT
28. Sect. 1 SENSIBLE HEAT Is Heat you ‘Can Feel’ Is measured with a Thermometer Causes a
29. Sect. 1 BRITISH THERMAL UNIT Measure of the quantity (amount) of heat energy Definition: A Btu
30. Sect. 1 SPECIFIC HEAT Amount of heat required to raise the temperature of one (1) pound
31. Sect. 1 SPECIFIC HEAT EXAMPLES Water - 1.0 Aluminum - .22 Honey - .35 Cheese -
32. Sect. 1 TERMS TO REMEMBER Temperature Box Temperature Ambient Temperature Sensible Heat Btu Specific Heat
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Sect. 1
What is Refrigeration?

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Sect. 1
DEFINITION
‘Refrigeration’…
…is the transfer of heat from a place where it

is ‘not wanted’…
… to a place where it is ‘unobjectionable’.

Слайд 4

Sect. 1
HEAT REMOVAL
If heat is removed from inside the container ‘faster’

than it enters...

…The internal temperature becomes colder.

Слайд 5

Sect. 1
WHAT IS HEAT?
A Form of Energy
It Exists ‘Everywhere’
It Exists at

‘All Temperatures’…Except…
Absolute Zero (-459º F / -273º C)
It can be Moved from ‘Place to Place’

Слайд 6

Sect. 1
WHAT ARE REEFERS?
Machines that ‘Move Heat’

Слайд 7

Sect. 1
‘HOW’ DOES HEAT MOVE?
Warmer ⇒ Colder - ALWAYS!!!!!!!
Heat
Heat
Heat
‘Faster’ with Large

Temp. Difference

Слайд 8

Sect. 1
‘HOW’ DOES IT MOVE?
Heat can move three (3) ways….
1. Conduction
2.

Convection
3. Radiation

Слайд 9

Sect. 1
CONDUCTION
Heat moves through Solids & Liquids

Слайд 10

Sect. 1
CONDUCTION
Heat will move Between Solids and / or Fluids

in direct contact with one another

Слайд 11

Sect. 1
CONDUCTION

Слайд 12

Sect. 1
Any other Examples of Conduction?

Слайд 13

Sect. 1
CONVECTION
Definition - Heat transfers via the circulation (movement) of a

fluid. i.e…..
Air is a fluid
Refrigerant Liquid & Vapor are fluids
Types
‘Natural’ Convection
‘Forced’ Convection

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Sect. 1
‘NATURAL’ CONVECTION
Warm Air Rises
Cool Air Falls
Heater

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Sect. 1
‘NATURAL’ CONVECTION

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Sect. 1
‘FORCED’ CONVECTION

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Sect. 1
‘FORCED’ CONVECTION

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Sect. 1
Any other Examples of Convection?

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Sect. 1
RADIATION
Moves in Straight Lines… like light
Does not heat the air

it passes through
Raises temperature of the substance that absorbs it
Dark colors absorb ‘more’ heat…
Light colors absorb ‘less’ heat

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Sect. 1
RADIATION

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Sect. 1
RADIATION

Слайд 22

Sect. 1
Any other Examples of Radiation?

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Sect. 1
HEAT TRANSFER SYSTEMS
Usually combine ‘Conduction’ AND ‘Convection’ to move heat.

i.e….

Слайд 24

Sect. 1
TERMS TO REMEMBER
Refrigeration
Heat
Box
Conduction
Convection
Radiation

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Sect. 1
HOW IS HEAT ‘MEASURED’?
Four (4) Ways….
Temperature
Sensible Heat
British Thermal Unit (BTU)
Specific

Heat

Слайд 26

Sect. 1
TEMPERATURE
Is the Level or Intensity of heat energy
Is measured

in degrees
Fahrenheit or Centigrade

Can be ‘Felt’ or ‘Sensed’

Слайд 27

Sect. 1
TEMPERATURE
The temperature inside the controlled space (container) is called….
Box Temperature
AMBIENT
AMBIENT
AMBIENT
AMBIENT
The

temperature surrounding the
Container is called…

Слайд 28

Sect. 1
SENSIBLE HEAT
Is Heat you ‘Can Feel’
Is measured with a

Thermometer

Causes a change in
Temperature

Слайд 29

Sect. 1
BRITISH THERMAL UNIT
Measure of the quantity (amount) of heat energy
Definition:

A Btu is the amount of heat required to raise the temperature of one (1) pound of water one (1) degree F

Слайд 30

Sect. 1
SPECIFIC HEAT
Amount of heat required to raise the temperature of

one (1) pound of a ‘Specific Substance’ one (1) degree F.

Compared to Water (1.0)
The less heat required to change substance temp., the lower the Specific Heat
The more heat required to change substance temp., the higher the Specific Heat

i.e. 0.75

Слайд 31

Sect. 1
SPECIFIC HEAT EXAMPLES
Water - 1.0
Aluminum - .22
Honey - .35
Cheese -

.50

Fresh Beef - .75
Vegetables - .90
Cucumbers & Watermelon - .97

Слайд 32

Sect. 1
TERMS TO REMEMBER
Temperature
Box Temperature
Ambient Temperature
Sensible Heat
Btu
Specific Heat