1. Candles at Christmas Michael de Podesta
NPL Christmas Lecture 2017

2. YeCandles at Christmas Michael de Podesta
NPLChristmas Lectures 2017

3. Gas
Air
Radiation
Liquid
Solid

4. Ye Chemical Reaction C25H52 + 38O2 25 CO2 + 26H2O Wax Oxygen
Carbon dioxide
Water

5. Wax is made of carbon and hydrogen
Reacts with Oxygen to make Water

6. It then makes Carbon Dioxide
…leaving nanoparticles of soot!

7. It then makes Carbon Dioxide
…leaving nanoparticles of soot…
…which heat up and glow…

8. Ye Video

9. Gas Radiation Liquid Solid Air (N2 and O2) Water (H2O)
Carbon Dioxide (CO2)
Soot (C)
Gas
Radiation
Liquid
Solid

10. More
Complexe
Picture

11. YeWax
is not flammable!

12. Ye Flame Structure

13. Wick
Evaporation
Pyrolisis

14. Smaller molecules are more reactive
Pyrolysis breaks apart Wax molecules
Smaller molecules are more reactive

15. Incomplete Combustion
Wick
Evaporation
Pyrolysis
Incomplete Combustion

16. Smaller molecules burn easilyHO HO
H2O
H2O
H2O HO
H2O
H2O
H2O HO

17. Smaller molecules burn easily
Partial Combustion leaves nanoparticles

18. Incomplete Combustion
Wick
Evaporation
Pyrolysis
Incomplete Combustion
Complete Combustion
Air

19. Incomplete combustion
Final combustion
Nano-particles
Incomplete combustion
Light Emission
Pyrolysis
Evaporation
Gas
Radiation
Liquid
Solid

20. Incomplete combustion
Nano-particles
Incomplete combustion
Light Emission
Final combustion
Pyrolysis
Evaporation
Wick

21. YeQuestions Temperature? Stored Energy? Available Power?
How much light?

22. Thermocouple
Gas
??? °C
Liquid
Solid

24. YeQuestions Temperature? More than 1000 °C Stored Energy?
Available Power?
How much light?

25. grams
grams
grams
grams
grams
grams
grams
grams
grams
grams
grams
grams

26. Calorific Value
43,100 joules per gram
Stored energy
1.8 Megajoules
(0.5 kW hours!)
Power
76 watts

27. YeQuestions Temperature? More than 1000 °C
Stored Energy? 1.8 mega joules
Available Power?
How much light?

28. Boom There is a lot of energy in a candle…AA AA
boooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooom AA AA
Dynamite AA AA AA AA AA AA
Energy Density
TNT: 4.6 kJ/g
Candle Wax 42 kJ/g
Alkaline Battery 0.5 kJ/g
Candle
Candle Mass = 42 g
Energy = 42 x 42 = 1764 kJ
Candle = 1764 / 12 kJ = 147 batteries
Battery
1 battery = 24 g
Per battery = 0.5 x 24 = 12 kJ

29. YeQuestions Temperature? More than 1000 °C
Stored Energy? 1.8 mega joules
Available Power? 76 watts?
How much light?

30. ??? °C

31. Heating rate is 0.132 °C per second
102.5 grams of water
Power
~60 watts
Heating rate is °C per second

32. YeQuestions Temperature? More than 1000 °C
Stored Energy? 1.8 mega joules
Available Power? 76 watts- Yes!
How much light?

33. Ye Integrating Sphere Ye Fibre-Optic Cable Ye Jolly Computer
Wavelength
Power
Ye Jolly Computer
Ye Spectrometer

34. YeQuestions Temperature? More than 1000 °C
Stored Energy? 1.8 mega joules
Available Power? 76 watts- Yes!
How much light? 0.2 watts

35. Questions& Answers
Could we do better?

36. Thermal Energy
‘Work’
100%
Conversion
is NOT possible

37. Stirling Engine

38. Thermoelectric Generator

39. Thermoelectric Generator
Ye U.S.B.

40. Summary
Candles are Amazing!

41. Thank You Alexandre Cuenat Stephanie Bell Paul Miller Claire Greenwell
Gavin Sutton Teresa Goodman
Stuart Davidson
Nigel Fox
Michael Faraday

42. Water!

43. Camera Shots required Close up shot of Candle flame
Close up of the burner melting wax
Close up of the thermocouple in the candle flame and also showing the reading on the thermocouple reader.
Close up of the weighing machine showing when the candle is lit. Should be able to see the scale on the weighing machine and the candle flame
Close up of the Conical Flask being heated.
Close up of Sterling engine #1
Close up of Sterling engine #2
Close up of TEG powered car.
Close up of TEG powered USB charger and light.

44. Candles at Christmas
Michael de Podesta