[TRNSYS-users] UWin for horizontal windows

[Antoine Gautier]

Dear users

 

I try to understand the discrepancy of UWin variations between an horizontal
window (slope=0 in Window Type Manager, blue line in attached chart) and a
vertical one (slope=90 in Window Type Manager, pink line in attached chart).

I guess that it is mainly due to the convective heat exchange coefficient
between the individual glazings. As specified in §5.4.2.4 of user manual,
the convective transfer is indeed calculated from the surface temperature
difference (red line in attached chart) and the slope of the window.

My questions now.

1/ Could anyone confirm that my guess is actually correct?

2/ What about the Nu computation in case of cos(Beta)=0 in Eq. 5.4.2-13?

3/ Uw values of manufactured windows should be quite different depending on
their intended orientation. Are the Uw values of roof windows specified with
increased convection effects?

 

Thanks a lot for your help on that !

--

Antoine Gautier
Solamen SAS
+33 6 58 24 02 60

antoine.gautier at solamen.fr

 

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