IES-VE User Forum

hello everybody
I would like to know if it is possible take in account the effect of different SRI ( solar refelctance index) from a external material on IES, becuase I'm trying to analize the impact on the internal temperature from an insulated aluminum roof, but one of the requirements is take in account the SRI index ( the idea is use a clear color, and compare with dark colors), but I don't know which parameters modify in IES or evenif it is possible to do on IES VE
some one have some suggestion or a explanation about this

thanks

Hi,

Pete in the Tech Support team has previously sent out this suggestion regarding SRI, you could look into this for your own study

we don’t have the solar reflectance index or albedo parameters but we do have emissivity and external solar absorptance. You should be able to derive solar absorptance therefore easily enough if you assume albedo (reflectance) + absorptance =1. If you do a google search for ASTM E 1980 (the SRI calculation procedure document) you will find some useful resources including an excel spreadsheet that might be handy.

Phil

I noticed that in the current 2014 version (2014.1.0.0) there is an "initial solar reflectance index" column as well as a "3-year aged solar reflectance index" column. Does this mean that IES can now take an SRI input instead of emissivity and absorptance?

Thanks,

Anna

Anna
The SRI inputs in the CDB tabular edit are for LEED reporting purposes only, and not used by either Apache or (Title 24) EnergyPlus.

Separately, the Title 24 module displays SRI inputs on an individual Roof construction, and these are passed to EnergyPlus.

Regards Donald