9 Total Transfer of Thermal Energy

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TOTAL TRANSFERTOPIC 9: TRANSFER OF THERMAL ENERGY

1Sunday, February 20, 2011


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TOTAL TRANSFER OF THERMAL ENERGY IN

EVERYDAY APPLIANCESWe need to consider these factors:

The purpose /

function of

the

appliances

Keep The

Thermal Energy

In

Minimize HeatLoss

Maximize Heat

Absorption

Maximize

Internal IR

Reflection



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EVERYDAY APPLIANCESWe need to consider these factors:

The purpose /

function of

the

appliances

Keep The

Thermal Energy

Out

Maximize Heat

Loss

Minimize HeatAbsorption

Maximize

External IR

Reflection



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POLYSTYRENE CONTAINERS

Hot Food Cold / Frozen Food



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Container Lid


Hot Food

Material of the container

Components of the container

Non-metal, polystyrene (Has trapped air)

-> Insulator - trap and minimise heat

from being conducted away to the

surrounding. (minimise conduction)

- stops heated air from rising and

transferring heat to the surrounding.

- prevents formation of convection

current.

White in colour.

-> Worst emitter of IR. (min. radiation)



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Cold / Frozen Food


Non-metal, polystyrene (has air pockets)

-> Insulator - minimise heat from beingconducted into the box.

White in colour.

-> Worst absorber of IR.



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TAKE-AWAY CUPS

Hot Drinks Cold Drinks



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TAKE-AWAY CUPS

Hot Drinks


Components of the container

Container Lid

Non-metal, paper.

-> Insulator - prevents heat from being

conducted away to the surrounding.

- stops heated air from rising and

transferring heat to the surrounding.

- prevents formation of convection

current.

White in colour.

-> Worst emitter of IR.



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TAKE-AWAY CUPS


Non-metal, plastic.

-> Insulator - minimise heat from being

conducted into the cup.



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THERMOS FLASK

Plastic stopper

Silvered inner walls

Hot or Cold contents

Vacuum

Plastic outer casing



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THERMOS FLASK

Components of the thermos flask

Plastic stopper

Silvered inner walls

Hot or Cold contents

Vacuum

Plastic outer casing



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COOKING POTS

Function ?

Thermal Transfer ?

Materials / Components ?



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SOLAR PANELS

Function ?

Thermal Transfer ?

Materials / Components ?



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ROOMS / BUILDINGSRooms and buildings in temperate / cold countries need to keep

the thermal energy in.

Keep The

Thermal Energy

In

Minimize Heat

Loss

from the Roof

from the Windows & Doors

from the Walls

from the Floors



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Minimize Heat

Loss

from the Roof

from the Walls

use of lagging materials to

line the ceiling / attic areas

use of double walls with insulating

materials in between the walls

use of non-metal materials



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Minimize Heat

Loss

from theWindows &

Doors

from the Floorsuse of carpets to cover all

the floors

use of double glazed windows

use of sealed doors



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ROOMS / BUILDINGS

Keep The

Thermal Energy

Out

Maximize Heat

Loss

Minimize HeatAbsorption

Maximize

External IR

Reflection

Rooms and buildings in warm / hot countries need to keep the

thermal energy out.

from the Roof

from the Windows

from the Walls



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ROOMS / BUILDINGS

Minimize Heat

Absorption

Rooms and buildings in warm / hot countries need to keep the

thermal energy out.

from the Walls use of white / light colours for

the outside walls



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ROOMS / BUILDINGS

Maximize Heat

Loss

Maximize

External IRReflection

Rooms and buildings in warm / hold countries need to keep the

thermal energy out.

from the Roof

from the Windows

use of dark coloured metal

use of reflective, glass windows

9 Total Transfer of Thermal Energy

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