[Bldg-sim] Modeling a Green Roof

[Chris Jones]

The main difference in winter insulation between green roof and the 
standard roof is the extra 1 1/2" expanded polystyrene panel 
"drainage layer" in the green roof.  If you add that to the standard 
roof and assume it is dry (as the analysis does) then it adds the 
extra R value and makes the comparison more equal.



At 04:52 PM 10/09/2010, Brian Fountain wrote:
>Chris,
>
>In my experience, the impact of a green roof on the building energy 
>is pretty small.  In the winter, the soil layer is reasonably 
>saturated so isn't adding much insulation.  In the summer, there is 
>some shading effect to reduce solar but it is difficult to quantify.
>
>Attached is "Greenroofs in Canada" which includes a look at the 
>energy impact of a greenroof on a building.  It does discuss some 
>modelling but the increase in insulation value seems excessive to me.
>
>Cheers,
>
>Brian
>


Chris Jones
14 Oneida Avenue
Toronto, ON M5J 2E3.
Tel.  416-203-7465
Fax. 416-946-1005