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Re: [EnergyPlus_Support] Glazing Construction

The calculations in WINDOW 5 use a fixed value for solar radiation at a normal incidence to the window.  The EnergyPlus solar radiation is variable and typically not normal to the surface.  The solar radiation in EnergyPlus varies with the day's weather and the incident angle.  Clear glass will reflect and absorb different amounts of solar radiation depending on the incident angle.  The most likely cause of the calculation differences you observe is the actual difference in solar radiation between the two calculations.  It would also be very difficult to identically correlate the two calculations because of the difference between a WINDOW 5 steady state calculation and an EnergyPlus transient calculation.

Ned Lyon

Senior Staff Engineer
Simpson Gumpertz & Heger Inc.

41 Seyon Street
Building #1, Suite 500
Waltham, MA  02453

Phone:  781-907-9000
Fax:  781-907-9009

>>> hannahyan@xxxxxxxxx 12/12/02 03:24PM >>>

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