[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[EnergyPlus_Support] Properties of roof sheets

Could someone clear up the different thermal properties of roof 
I have data from a McGraw-Hill book with a chart indicating the 
following for new galvanised sheet:

Solar reflectance 0.35
Solar absorbtance (inverse of refl.) 0.65
Far IR emissivity 0.15-0.23
Far IR reflectance (inverse of emissivity) 0.77--.85

BLASTMaterials.IDF (included in E+ DataSets directory) has the 

 MATERIAL:Regular,METAL - GALVANIZED STEEL 1 / 16 IN,  !- Material 
 Smooth,  !- Roughness
  1.6000000E-03,  !- Thickness {m}
   45.31000    ,   !- Conductivity {w/m-K}
   7833.020    ,   !- Density {kg/m3}
   500.0000    ,   !- Specific Heat {J/kg-K}
  0.9000000    ,   !- Thermal Emittance
  0.2300000    ,   !- Solar Absorptance
  0.2300000    ;   !- Visible Absorptance

This seems to be quite different. What are the correct figures to use?

What are the relevant figures for different coloured painted steel 
corrugated roof sheets, e.g. white, light green ?


------------------------ Yahoo! Groups Sponsor ---------------------~-->
Buy Ink Cartridges or Refill Kits for your HP, Epson, Canon or Lexmark
Printer at MyInks.com.  Free s/h on orders $50 or more to the US & Canada.

The primary EnergyPlus web site is found at:

The group web site is:

Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
Yahoo! Groups Links

<*> To visit your group on the web, go to:

<*> To unsubscribe from this group, send an email to:

<*> Your use of Yahoo! Groups is subject to: