Maximizing Efficiency: Using Luxeon S LEDs for Solar Simulator Design

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Discussion Overview

The discussion revolves around the design of a solar simulator using Luxeon S LEDs, specifically aiming to achieve a net intensity equivalent to 1 Sun (1000 W/m²). Participants explore the challenges related to the spectral output of LEDs compared to natural sunlight and the implications for accuracy in simulation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes the specifications of the Luxeon S LEDs, including luminous and radiant flux, and expresses the goal of achieving a specific intensity.
  • Another participant highlights the differences between the light spectrum of high-power LEDs (HPLEDs) and that of solar light at sea level.
  • There is a suggestion that filters might be helpful in addressing spectral differences, though this is met with skepticism regarding their effectiveness in providing missing spectral lines.
  • A participant emphasizes the challenge of accurately simulating sunlight, regardless of the methods employed.
  • Concerns are raised about the area over which the radiant flux is distributed, with calculations suggesting that a single LED may only illuminate a small area to achieve the desired intensity.
  • Discussion includes the role of phosphors in producing white light from UV LEDs and the importance of color temperature in the context of LED output.
  • One participant warns about the potential quality issues with cheaper imitations of Luxeon products based on personal experience.

Areas of Agreement / Disagreement

Participants express varying views on the effectiveness of filters and the feasibility of achieving accurate sunlight simulation with LEDs. There is no consensus on the best approach to tackle the challenges presented.

Contextual Notes

Participants acknowledge the limitations of LED spectral output compared to sunlight, particularly regarding infrared content and the need for specific spectral characteristics in the simulator.

jefinjo
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I want to make a solar simulator with LEDs. I want to get a net intensity of 1 Sun(1000 W/m^2). My LEDs have the following specifications:

LUXEON S LXS8-PW30

Luminous flux at 700 mA, 85°C* 1315 lm

Radiant flux at 700 mA, 85°C 4113 mW

1931 CIE color points at 700 mA, 85°C (0.4304, 0.4030)

CCT at 700 mA, 85°C 3105 K

Distance to detector: 200 mm
 
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There are important differences between HPLED's light spectrum and solar sea level light spectrum
 
zoki85 said:
There are important differences between HPLED's light spectrum and solar sea level light spectrum
Yes. How can we tackle it? Are filters helpful?
 
I think it is a very challenging task if you want to be accurate, no matter what method and means you use.
 
jefinjo said:
Yes. How can we tackle it? Are filters helpful?
A filter cannot supply the missing spectral lines in the light that comes out of an LED. LED's are designed to provide a 'sort of' match to the light of a black body radiator (tungsten filament or sunlight) using three or more LEDs, each of which will only produce a narrow band of wavelengths.

It would all depend upon what you actually want from this 'simulator' and what the light will be used for.
 
jefinjo said:
I want to get a net intensity of 1 Sun(1000 W/m^2).

Over how much area ?
If we believe this
jefinjo said:
Radiant flux at 700 mA, 85°C 4113 mW
That led puts out 0.4 watts of radiant energy... so one of them will illuminate .0004m^2 to that intensity, about a 2 cm square.

http://www.philipslumileds.com/products/luxeon-s/

Last time i looked into them white LED's used a phosphor to make "white" light from a UV led's emissions, much like a flourescent tube.
Various phosphors make various shades of white...
You might read up on "color temperature"
http://en.wikipedia.org/wiki/Color_temperature
because i notice your LED comes in various color temperatures

Lastly, sunlight is about half infrared and your LED won't contain nearly that much. See its spectrum on the datasheets at Phillips.

Those Luxeons are a grreat product. Beware of the cheap Chinese imitations, the ones i tried were disappointing.