bUOYANCY DRIVEN NATURAL CONVECTION FLOW IN SOLAR CHIMNEY
 

Hello,
I am modelling a solar chimney which is a part of Net Zero energy building. Here, the dimensions of the chimney are 14'2" X 6'11" X 7'4". the chimney is rectangular in shape and the top 6' of the chimney on three surfaces has low emission windows and the bottom part is face brick wall. The absorber wall is a wall of gypsum board and is painted with white paint. The model is 3D and I am using ANSYS 14.5 for modelling the chimney

The flow in chimney is laminar flow and I am using S2S radiation model in solar ray tracing for the solar ray data.

In this case, I want suggestion how can I model low emission windows in fluent? and how can i give boundary condition for the low emission windows and white painted absorber wall? I want constant temperature boundary condition at all surfaces. Currently for the Low E surfaces I have used internal emissivity as 0.029 and temperature as was measured, is this enough? I did the same thing for the white painted wall. Please suggest how can I model Low E windows and white painted wall?

Also, at velocity inlet boundary i have specified 0 pressure and at pressure outlet boundary static atmospheric pressure of 747.8 mmHg is specified. In operating conditions dialog box, i specified pressure as 0. Please suggest if this is correct? And also suggest what should be appropriated pressure in this case and at which boundary?

and also, in materials when I use ideal gas for air and specified operating density as 0, when i initialize the case and run simulation there is error message as "Error: Divergence detected in AMG solver: pressure correction" Please suggest what should I change to correct this error

I am new to ANSYS FLUENT so i am facing some difficulties

Can you please reply in English?
Thanks

Low E windows question
 

I think the way you need to do this is solve radition using the DO model, use 2 Bands, one for small wavelengths (visible light) and one for large wavelengths (IR). Then set the emissivity of the windows to high (0.9) for the high band and (0.1) for the visible band.

Hope this helps

Sincererly,
Bill Wangard, Ph.D.
Engrana LLC

Hi, Bill.
I think in this case most of large wavelengths(IR) are reflected which means low emissivity for the high band.
I am also beginner and I am still confused about this.