Evaluation of Omni-heat performance

[Stephen Seeber]

I have been enjoying the discussion on this forum and decided to post my own contribution.

There are a growing number of clothing manufacturers who produce clothing with so called IR or infrared enhancements.  I am sure many people wonder about the effectiveness of these garments.  In order to shed some light on this, I have performed a quantitative assessment of a garment produced by Columbia Sportswear.  Let me know if you find this of interest or have any questions.

I intend to post similar studies from time to time.

The document may be found here:

https://www.dropbox.com/s/d5nn6e9xfdj2b38/Columbia%20OmniHeat%20Evaluation%20121918.pdf?dl=0

 

[Ben H.]

Nice!  Very well done.  This technique may actually work on the outside of the jacket where the insulation acts as a barrier to conduction, but I doubt that would give a jacket that meets the style requirements of marketing.  It would be interesting to turn the jacket over and see how it performs.  Is that what we are looking at in the second photo?  I don’t think you have set up a thermal gradient across the jacket in that test.. correct?

[Jerry Adams]

yeah. nicely done

sounds like the Omniheat is marketing hype more than an innovative product

yeah, how did you measure R value?

[Daryl and Daryl]

Thanks.

Very pleasant reading.

Thanks for spoon feeding/dumbing down the info so I could understand it.

[Stephen Seeber]

HI All:

Here are some replies:

Ben H: The technique would be more effective on the outside of the jacket as a radiant barrier.  However, not by much, since the emissivity  is actually pretty high at about .7.  This material is no space blanket. Concerning the second image:  We are doing the test  by imaging the exterior of the jacket.  The Omni-heat layer is resting directly on the heat source.  I do measure the temperature gradient from one side to the other.  You need deltaT to calculate the thermal performance of the jacket.

Jerry:  I measure the temperature on both sides of the jacket.  With the temperature data, I can calculate Q, energy loss through the jacket for both radiative and convective transfer.  After I know Q I can then calculate conductivity and from there, R-value.  The measurement performance of the system is verified using insulation standards with known R-values.

Daryl:  You are welcome.

 

 

 

 

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