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Teaser Infrared Image - The Answer

Hmm, did this week’s infrared image stump you guys?

Infrared Image

Visible Light Image

Answer: Image is of defective cells within a solar panel—and the image was taken at a solar installation in Europe! Defective cells decrease the output of the entire panel, meaning the panel is not producing as much power as it could be.  It is very important to use infrared to detect a problem like this, because troubleshooting rows and rows of solar panels can be extremely time consuming, and not to mention, costly!  By using an infrared camera, defective cells can be spotted much quicker, as well as from a distance.

Good thinking, Dan, about the image being from B.C.!  I probably would have guessed that too—but we like to be a bit tricky :).  Stay tuned for next week’s teaser infrared image!

10 comments to Teaser Infrared Image – The Answer

  • […] This post was mentioned on Twitter by Fluke Thermography, Fluke Thermography. Fluke Thermography said: The answer is up for this week's teaser #infrared image! Did we stump you guys? Well prepare to be "un-stumped": […]

  • Dan Laughbon

    Good one guys!, I’VE not had the oppurtunity to look at a solar panel.

  • Now that was a tough one; unless you’re a solar pro, it’s like looking at a completely unrecognizable image. Cool though!

  • Fluke Thermography

    Thanks, glad you enjoyed the image this week! It was a tough one, but hopefully today’s will come a little easier.

  • i could only wish that solar panels cost only several hundred dollars, i would love to fill my roof with solar panels *:-

  • How did they address the reflective nature of the glass? I have looked at panels and the frame is hot but the center is cool from the reflection.

  • Michael Stuart


    Nice to see you on the blog. Great Question.

    Actually, typical glass is not as thermally reflective as most people think. It has an emissivity of .85 (unless it is low e glass), which means that only the remaining 15% of the infrared energy is possibly coming from thermal reflections (or maybe a little transmision). (Remember the RAT law? R+A+T=1)

    If the reflected background is uniform, such as with uniform cloud cover, or the cold sky, you should still be able to discern if there are any abnomrally hot cells within the panel. Trying to get an accurate temperature measurement on those hot cells is problematic, however… because of the emissivity and the energy from the background.

    If you want to verify that what you are seeing is not a thermal reflection, the use of the “Thermographer Two-step Dance” is in order… just move from side to side to see if the spot moves with you or not. (I have seen people find “hot spots” on solar panels that were really only reflections of the sun or an aircraft in the sky.)

    Another way to verify is to look at the bottom side of the panel. Infrared energy (or heat) always travels from hot to cold… regardless of orientation to gravity or up/down/sideways.

    Here’s an experiment that some people may want to try. First, look at your thermal reflection in a pane of glass. Next, place your hand on the pane of glass for twenty seconds. Now step back again and look at the scene. 15% or so of the energy that your camera is detecting is from your thermal reflection and the remainder of the reflected background. The other 85% is coming from the surface of the glass… which has the heat that your hand imparted on it a minute earlier (through conduction) and is now being emitted again.

    Sorry for the long answer, but hopefully this helps all of the readers understand a little better.

  • I hardly leave a response, however i did some searching
    and wound up here Teaser Infrared Image – The Answer |
    Thermal Imaging Blog from Fluke Thermography.
    And I do have some questions for you if it’s allright.
    Is it only me or does it look like some of the responses look like left by brain dead
    visitors? 😛 And, if you are posting at additional social sites, I’d like to
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    like your Facebook page, twitter feed, or linkedin profile?

  • Fluke Thermography

    Thanks for your post. You can check us out on Facebook @

  • Mark Yang

    What Fluke Ti series would have the minimum required sensitivity for inspecting solar array installations? In particular, is TiS sufficient?