Hello,
This may be a very naive question, but please bear with me.
I have noticed that many solar simulators used in papers on photocatalysis and solar evaporation have xenon lamps that have a power rating of 450 watts for example.
How then does it achieve an irradiance of 1000W/m2? Do these solar simulators have utilize lenses to increase the intensity?
Thank you
What will be if you illuminate a sell/module with area 0.45m2 or less? Does that answer your question?
By using a concentrator (lenses or spherical mirrors), the light from the lamp can be focused onto a small area to achieve higher wattage per unit area.
In your example, the total power is 450 watts and irradiance of 1000 w/m2 is required therefore if you focus all of 450 watts of light onto an area of 0.45m2, you will get an irradiance of 1000 w/m2.
Most solar simulators can achieve high output because they are compact, use mirrors, lenses and spectral filters, and only illuminate a very small area at short distance from the light source.
See http://www.sciencetech-inc.com/all-products/light-sources/solar-simulators.html
https://g2voptics.com/solar-simulation/
The solar radiation field incident above the cloudy layer is uniform. But below that layer, the radiation field reaching the surface is not uniform, and Earth's surface irradiation may exhibit patches of enhanced radiation intensity. In case of scattered and high reflectivity clouds the irradiation at the surface may exceed one sun.
This may help: https://authors.elsevier.com/c/1cv~B4sIlksnr0
Unfortunately, Rui misunderstood the question completely. He talks about the cloud enhancement phenomenon in nature, as described in e.g. Article Cloud and albedo enhancement impacts on solar irradiance usi...
To clarify, the question was about solar simulators for lab work, as described in many documents:
https://www.youtube.com/watch?v=YOf2N9gMum0
https://en.wikipedia.org/wiki/Solar_simulator
sciencetech-inc.com/fileuploader/download/download/?d=0&file=custom%2Fupload%2FFile-1386095946.pdf
https://www.newport.com/medias/sys_master/software/software/h5a/h26/9342467440670/m940x3A.pdf
As mentioned above solar simulators (with Xenon lamps) use mirrors and lenses to focuse the output light in a parallel or concentrated bean. That increase the total irradiance on the target.
The distance, 'between the source and the target; is also a key factor. On the other hand, the use of spectral filter(s) will reduce the total observed irradiance.
Hope it can help you
Dr. Didier GILLOTAY
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