Hi,

We are trying to do an experiment about knowing the temperature value by which the solar panel would then experience a decrease in power output in voltage. In other words, finding the temperature where significant changes in the power output could already be observed. So, we are planning to do the testing in a controlled environment because we could not account for the diffused radiation and reflected radiation if it were outdoors. We are only concerned with direct irradiance.

Our concern is the alternative lighting we would use in the experiment to mimic the effect of sunlight. We are planning to use varibeam 800 (specs are...max 800W 220/240 V) that are used for photography. We would like to ask if this lighting could give somewhat similar wavelength spectrum as the sun does and have an effect similar to the sun. Any suggestions would really help. Thank you

 

As long as the illumination is at a fixed value, the output from the PV cell should remain constant (assuming a constant temperature). You can always go to the manufacturer and get the spectral output from the lamps. You should also check this experimentally.

The important thing is to hold the illumination constant so any variation on PV output can be related to temperature, assuming you find that constant illumination does not vary with some variable that is not temperature. That's why you need to do the constant illumination, constant temperature experiment.

 

I think you'll want to thermally isolate your light source from your panel, so that when you change the panel temp, the bulb ambient temperature does not change. Otherwise you could end up studying the effect of ambient temperature on bulb output. I doubt that's much of a factor really, but you need to either eliminate or measure it. Easier to eliminate it.

 

The varibeam 800 lamp seems to be a Osram 64571 3200K bulb. A 5800K source might match the suns spectrum better.

http://en.wikipedia.org/wiki/Air_mass_coefficient
http://www.google.com/url?sa=t&sour...GnKOd_md8REC0cH-w&sig2=JjJNSwhwWdqeRoFXGhqrIg

http://zeiss-campus.magnet.fsu.edu/articles/lightsources/tungstenhalogen.html

http://entropyproduction.blogspot.com/2005/08/air-mass-15-standard.html