1. Modelling plasmas for light generation -
Some thoughts on the needs of the lighting industry
COST Model Inventory Workshop
12 to 15 April 2005
University of Madeira, Funchal
Stuart Mucklejohn
UK National Representative to COST529
GE Consumer & Industrial- Lighting, Melton Road, Leicester LE4 7PD, UK
April 2005
COST529_April05.ppt

2. What are models used for ?
New product development
Product improvement
Fault finding
Production processes
Education
Training
April 2005
COST529_April05.ppt

3. Light generating component of a system used to illuminate things
What is a lamp ?
Light generating component of a system used to illuminate things
Within the European Union:
An energy using product (EUP)
A product subject to the WEEE directive
A product subject to the RoHS regulations
April 2005
COST529_April05.ppt

4. A light emitting high temperature chemical reactor
What is a high intensity discharge (HID) lamp ?
A light emitting high temperature chemical reactor
Characteristics:
Plasma has electron temperature = gas temperature
Operating pressure 1 to 50 atm, up to 200 atm for UHP
Local thermodynamic equilibrium is a reasonable assumption
April 2005
COST529_April05.ppt

5. Uses of HID lamps Road lighting Car headlamps Stage/studio lighting
Horticulture – greenhouse lighting
Interior lighting – warehouses & shopping malls
Floodlighting – sports & architectural
Projection systems
April 2005
COST529_April05.ppt

6. Types of HID lamps Description Typical application
Low-pressure sodium road lighting
High-pressure sodium road lighting
High-pressure mercury road lighting
Metal halide with silica arctube interior, sports, malls
Metal halide with ceramic arctube interior, malls, streets
Ultra high pressure projection systems
April 2005
COST529_April05.ppt

7. Some characteristics of HID lamps
Power range 20 to 20 kW
Output to lumens
Life to h
Size 50 to 500 mm
Global market >500x106 € per annum
April 2005
COST529_April05.ppt

8. The system includes light source & the receptor
April 2005
COST529_April05.ppt

9. Components of HID lamps
Outer enclosure - glass outer jacket & metal connectors
Arctube - silica or ceramic
Electrodes - tungsten
Leadwires – molybdenum, niobium
Chemical additives - mercury, sodium, metal halides
Gas fill - argon, krypton85
Joins
Seals
April 2005
COST529_April05.ppt

10. A metal halide lamp with ceramic arctube
April 2005
COST529_April05.ppt

11. Interactions within HID arctubes
Gas phase to 6000 K light generation
Liquid – Gas 700 to 1300 K dose evaporation
Solid – Gas 700 to 1500 K corrosion
Liquid – Solid 700 to 1300 K corrosion
Solid – Solid 700 to 1500 K corrosion
April 2005
COST529_April05.ppt

12. Temporal phenomena Steady state Transient Non-LTE Reaction kinetics
April 2005
COST529_April05.ppt

13. Energy balance for a metal halide lamp
From Philips Lighting & the ALITE program
April 2005
COST529_April05.ppt

14. Life cycle of HID lamps Assumes life of 10000 h
Production Raw materials, processes, testing
0 to 100 h Rapidly changing properties to 100 h
100 to 1000 h Significant changes in output
1000 to h Slowly changing output, failures
End of life Disposal
Recycling
Environmental impact
April 2005
COST529_April05.ppt

15. Fundamental data
Radiation properties of optically thick radiators (line broadening, transitions probabilities)
Radiation properties of optically thin radiators (reduced emission coefficients)
Diffusion coefficients & mobilities of plasma species
Viscosities of buffer gases
Thermochemical parameters for: plasma species (discharge properties)
liquid - gas reactions (dose chemistry)
solid - gas reactions (corrosion)
solid - liquid reactions (corrosion)
Kinetic parameters for material transport mechanisms
April 2005
COST529_April05.ppt

16. Examples of predictive models needed
Lamp voltage rise through life
Lamp voltage & colour changes for vertical & horizontal operation
Luminous efficacy through life
Output from 200 to 3000 nm
Lamp life
April 2005
COST529_April05.ppt

17. History Many descriptions of models at conferences
Large number of scientific publications
Valuable resource for the lighting industry
But ……..
Some reports/papers very difficult to find
Software no longer available & not designed for operation by third parties
April 2005
COST529_April05.ppt

18. April 2005
COST529_April05.ppt

19. April 2005
COST529_April05.ppt

20. Acknowledgements Barry Preston (GE Lighting)
Many thanks to:
Barry Preston (GE Lighting)
Raghu Ramaiah (GE Lighting)
April 2005
COST529_April05.ppt