[esp-r] Re: separate zone as air gap

[Jon Hand (clcv10)]

>
A recent question about changing surface absorption...

> 1) Can anyone tell me how to create a black absorber paint  
> (absorptivity of 0.9) on the 'external' surface of a wall mass. Can  
> I do this by simply change the absorptivity of the wall mass in the  
> material database?
>
Yes this is the correct approach. Find an existing material in the  
database and make a
copy of it giving the copy a suitably different name and then adjust  
its solar absorption.

> 2) I have created a separate zone for 20mm air gap between a  
> internal wall mass and a layer of TIM. The software requires a  
> specification of construction material for top, side and bottom  
> surfaces of the zone. What is the best solution for this?
>
A zone in ESP-r must be fully bounded. Just because it is only 20mm  
from front
to back there still will be a top and a bottom and sides.  You could  
have defined
this using the in-built create a zone from a rectangle (which would  
have created
the polygons for the top and bottom and sides). Otherwise you are  
going to have
to manually add surfaces between the existing front and back  
surfaces. The menu showing the list of surfaces and their edges has  
an option to 'add' a surface by clicking on existing
points or typing in the indices of the existing vertices. The help  
associated with this
part of the interface tells you the rules that must be followed when  
creating a surface
(e.g. you can't do a mobius strip as a surface, the order of the  
edges tells esp-r
which way the surface is facing).

Given that one of the existing dimensions is 20mm it will be  
difficult to see what
you are doing in the interface.  So, advise is to scrap this partial  
zone and create
it using the rectangular option.

-ESRU

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