Re: [TRNSYS-users] Wind loss modeling

[David Bradley <bradley@tess-inc.com>]

John,
  Most of the building models in TRNSYS simply ask for the user to
supply the external heat transfer coefficient so you can treat it however
you like. The algorithm that I usually use is from ASRHAE:

h = (AA+BB*WindVel+CC*WindVel**2)*3.6

where h is the external convection coefficient in kJ/h.m2, AA, BB, and CC
are empirical coefficients that depend on the exterior surface material
and WindVel is the wind speed in m/s. The AA, BB and CC coefficients
(again from ASHRAE) would be:

        

        

        

AA

      

BB

      

CC
Stucco

  

        

11.58

   

5.894

   

0.0
Brick

   

        

        

12.49

   

4.065

   

0.028
Concrete

        

        

10.79

   

4.192

   

0.0
Wood

    

        

        

8.23

    

4.00

    

-0.057
Smooth
plaster

  

10.22

   

3.1

     

0.0
Glass

   

        

        

8.23

    

3.33

    

-0.036

Cheers,
 David


At 13:30 9/12/2007, J.A. Palyvos wrote:

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Dear all,
 
I would appreciate any information on the external forced convection algorithms (i.e. wind loss coefficient expressions) used in TRNSYS.(I am aware of the McAdams/Jurges linear relation used in Type 19).
 
Many thanks,
 
J.A. Palyvos, NTUA
Athens
 
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