[Bldg-sim] measurement of SHGC in the field

[Nathan Brown]

Hi Chris —

That instrument won’t do it, because it is not sensitive to infrared. More than half of irradiance is in the near IR (aka solar infrared). You need a pyranometer (LiCor is our go-to <https://www.licor.com/env/products/light/pyranometer.html>, or an Eppley <http://www.eppleylab.com/instrument-list/standard-precision-pyranometer/> for critical measurements, although that is probably overkill for this). I would measure vertical irradiance just inside and just outside the glass under direct sunlight. Here in the Bay Area, there is a tool lending library that will loan a pyranometer. Perhaps you can find a similar source closer to you.

Best,
Nathan

Nathan Brown, BEMP, LEED AP ~ Associate
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> On Nov 10, 2017, at 3:08 AM, Chris Yates via Bldg-sim <bldg-sim at lists.onebuilding.org> wrote:
> 
> Dear all
> 
> We are trying to get a reasonable estimate for SHGC in the field.
> 
> Our project is a retrofit of a relatively recent build that has overheating problems. No records exist of the original glazing spec.
> 
> The glazing has a slight green tint; i.e. the "look and feel" of a fairly modern spectrally selective product with g-value (sorry SHGC) of about 0.4. However, a team member has now produced some records indicating this is significantly higher (more like 0.6).
> 
> Does anybody have any experience or know of any research relating to this?
> 
> I was thinking of something like this, taking measurements on the horizontal and vertical plane inside and out: https://www.uv-light.co.uk/meters/irradiance-and-exposure/ <https://www.uv-light.co.uk/meters/irradiance-and-exposure/>
> 
> Our saint gobain rep tells me their spectrographic equipment is 50,000 GBP - a bit out of our price range! (They've offered to test a sample for us!).
> 
> Cheers
> 
> Chris
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