[TRNSYS-users] Solar radiation in high glazed spaces

[Freppel, Wirich]

Dear Trnsys users,

I'm trying to assess thermal comfort in a high glazed space (like a porch/veranda) with TRNSYS 18. I built a model, which geometrically corresponds to an experimental veranda we have at the lab.
I did temperature measurements in the experimental facility under solar radiation and then I compared it to the simulation.

All calculation are set in "detailed mode" to take view factors into account. As a result, air temperature is much lower in the simulation, a lot much lower. And the most surprising fact is that when I set the solar to air factor to 1, both air temperatures match pretty well.
I concluded from this result that, if I transform all the supposed radiative flux into convection, the thermal balance in the simulation is equal to the experimentation. But when I consider radiative flux from glazings, the radiative part is missed by the simulation, resulting in a much lower air temperature in the simulation. It is like a part of radiative flux disappeared right after passing through the glazings.

I only used Type 56 to model the high glazed building. Is there a better solution, like a specific type which can do solar radiation calculation in a 100% glazed building ? Or should it work fine with Type 56 only ?
(of course I can send the project if needed)

Many thanks in advance
Best regards

Wirich FREPPEL
Development engineer
COSMOS - Buildings Energy Performance & Daylighting Group
Cell: +33 637 053 174
Saint-Gobain Research Compiègne

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