10 UOC Greece Green Heating

Green HeatingAlikianos Lyceum,Crete, Hellas

“Kelvin William”Georgiakakis EftychiosDimitroulakis Ioannis

Katzaki MariaKaragkezidi Veronika

Kourgiantaki Konstantina

Green Heating

Energy sources:

• renewable and environmentally benign

• cost effective

• minimum waste

The Electromagnetic Spectrum

Infrared radiation provides more heating

Light Wave Interactions

When a light wave strikes an object, it could be:

absorbed

reflected

transmitted

Light Absorption

If a light wave is absorbed when it strikes an object, its energy is converted to heat

Does the same apply to both

matte and glossy surfaces?

Absorption

Heat

Light ReflectionIt involves two rays:•an incoming or incident ray and•an outgoing or reflected ray

When a light wave

strikes a

glossy surface,

it is partly reflected.

Some of the energy is lost.

Colour and Light

•The colour of an object is not actually within the object itself

• Each frequency corresponds to a specific colour

• Colour is a sensation

Why Black?

•Different colours absorb different amounts of light

•The more light a colour absorbs, the more thermal energy it produces

• Black is good absorber of light, it absorbs all colours

Heat Transfer

Exchange of thermal energy between physical systems depends on temperature

•conduction

•convection

•radiation

Our Hypothesis

A matte black surface should absorbmore radiation than a glossy black oneas the latter should reflect light tosome extent

Objective

To determine:

Which surface absorbs more radiation?

A black matte surface?

or

A black glossy surface ?

Light Absorption from Coloured Materials

Light Absorption from Colored Materials

400 500 600 700 800 900 1000 1100

-20

0

20

40

60

80

100

% T

ran

sm

itta

nce

Wavelength (nm)

No Filter

Red filter

Dark Blue filter

Matte or Glossy? Experimental setup

Matte Glossy

Variables

Some Problems:

• Water quantity not the same

• Temperature measurements were not taken simultaneously

• Unstable weather conditions

Temperature Measurements of Water

Parameters

• Equal amount of water

• Two same thermometers and a timer

• Two different heat sources

Under sunlight and incandescent

bulb

Time(min)

Glossy Surface (°C)

Matte surface (°C)

0' 19,8 °C 19,1 °C

5' 20,7 °C 20,1 °C

10' 21,3 °C 21,3 °C

15' 22,2 °C 21,7 °C

20' 22,8 °C 22,2 °C

25' 24,0 °C 23,5 °C

Time(min)


Matte surface (°C)

0' 16 °C 16 °C

10' 18,5 °C 19 °C

20' 20,5 °C 21,5 °C

30' 21,5 °C 24 °C

40' 24 °C 27 °C

50' 26 °C 28,5 °C

Incandescent bulb Sunlight


Results

Incandescent bulb Sunlight


Results

15

20

25

30

0' 10' 20' 30' 40' 50'

Time (min)

Te

mp

era

tu

re (

°C

)

.

Glossy Surface Matte surface

15

20

25

30

0' 5' 10' 15' 20' 25'

Time (min)

Te

mp

era

tu

re

(°

C)

.

Glossy Surface Matte surface

ΔT = 4.2oC

ΔT = 4.4oC

• Equal quantity of water

• Use of two thermometers

• Use of timer

• Infrared and Halogen light bulbs

Parameters


Under Infrared and Halogen bulb

Time (min)


Matte Surface

(°C)

0' 12 °C 12 °C

5' 13 °C 14 °C

10' 14 °C 17 °C

15' 16 °C 20 °C

20' 17,5 °C 23 °C

Time (min)


MatteSurface

(°C)

0' 16 °C 16 °C

5' 17 °C 18 °C

10' 17,5 °C 19,5 °C

15' 19 °C 21 °C

20' 21 °C 23 °C

ResultsInfrared bulb Halogen bulb


Infrared bulb Halogen bulb


Results

10

15

20

25

30

0' 5' 10' 15' 20'

Time (min)

Te

mp

era

tu

re

(°

C)

. Glossy surface Matte surface

10

15

20

25

30

0' 5' 10' 15' 20'

Time (min)

Te

mp

era

tu

re

(°

C)

. Glossy surface Matte surface

Conclusions

Based on our results we concluded that:

A matte surface

absorbs more radiation than

a glossy one

Our Classmates…

Team : Food for Thought

Surfaces that absorb and reflect visible light absorb and reflect infrared too

Team: X-Rays

Black colour absorbs infrared radiation better than others

Team: Little Explorers

A 70 degree tilt is more effective for solar radiation absorbance

All Together…Taking all these conclusions into account we set up our own solar panel

Applications

• matte surfacee.g. building facades and

solar water heaters

• glossy surface e.g. tanks with flammable

and sensitive content

What’s next?

As a follow up, we could further explore

heat absorption

References• Marianne C. Lancaster Ebenezer Middle School Rincon Georgia

http://www.effinghamschools.com/cms/lib4/GA01000314/Centricity/Domain/702/573-579.pdf

• Tom Henderson Glenbrook South High School, Glenview, Illinoishttp://www.physicsclassroom.com/class/light/Lesson-2/Light-Absorption,-Reflection,-and-Transmission

• Holman, J.P. (1986), Heat Transfer, 6th ed., McGraw-Hill, Inc.http://www.efunda.com/formulae/heat_transfer/home/overview.cfm

• University of Waikato Science learning Hub 2012http://sciencelearn.org.nz/Contexts/Light-and-Sight/Science-Ideas-and-Concepts/

• Tom Henderson Glenbrook South High School, Glenview, Illinoishttp://www.physicsclassroom.com/class/refln/Lesson-1/The-Law-of-Reflection

• April Koch http://study.com/academy/lesson/color-white-light-reflection-absorption.html

• Matt Williams, 2011 Absorption of Light http://www.universetoday.com/87943/absorption-of-light/

• G. Nellis , S. Klein Cambridge Engineeringhttp://www.cambridge.org/us/engineering/author/nellisandklein/

Thank you for your attention!

10 UOC Greece Green Heating

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