[TRNSYS-users] ts15-type 56 effect of wind on heating load

[David Bradley [SEL]]

Dear Xavier,
  Wind effects on buildings are quite complex, depending on building 
geometry, on wind speed, on wind direction, on penetrations through the 
building envelope (doors, windows, etc.) and on local terrain (trees, 
surrounding buildings, etc.). TRNSYS includes a number of methods for 
estimating these effects. If all you want is a very basic estimation of 
a wind speed dependent heat transfer coefficient, you can use the ASHRAE 
equation:

h = a1 + a2*V + a3*V^2

where a1, a2, and a3 are in W/K.m2 and depend on the exterior surface 
material. For stucco, a1 = 11.58, a2 = 5.894, and a3 = 0. For glass, a1 
= 8.23, a2 = 3.33 and a3 = -0.036. (From ASHRAE Standard 140)

The next step up in complexity of predicting the effect of wind induced 
infiltration is to use one of ASHRAE's simplified methods: either the 
K1, K2, K3 approach, or the Sherman Grimsrud equation. There are 
components in the TESS Utility Library that will calculate infiltration 
using these methods.

The final level of complexity is to make use of standard TRNSYS Type157 
(connection to COMIS) or Type97 (Connection to CONTAM). These components 
provided data links between TRNSYS and two different airflow modelling 
tools. There is some redundancy of data entry in that you have to 
describe the building thermal model in TRNBuild, then describe the 
building geometry in CONTAM or COMIS. Once defined, however, the 
programs work together to do combined thermal / airflow modeling of the 
building. COMIS is available as an add on to TRNSYS from CSTB. CONTAM is 
freely available for the US National Institute of Standards and 
Technologies (http://www.bfrl.nist.gov/IAQanalysis/CONTAMWdesc.htm). As 
a final alternative, you can use another TRNSYS add-on called TRNFLOW. 
TRNFLOW is an adaptation of COMIS. It is available from Transsolar and 
provides a combined front end for the specification of both the airflow 
and the thermal model inside TRNBuild.
Kind regards,
  David



Xavier Dequaire wrote:

>Hi,
>
>type 56 does not take wind  as an input,
>
>Any method to simulate the effects of wind on the energy consumption of
>the building?
>
>thank you
>
>Xavier D.
>
>_______________________________________________
>TRNSYS-users mailing list
>TRNSYS-users at engr.wisc.edu
>https://www.cae.wisc.edu/mailman/listinfo/trnsys-users
>  
>

-- 
**
David BRADLEY
Solar Energy Laboratory
University of Wisconsin - Madison
1500 Engineering Drive
Madison, WI  53706
United States

Ph: +1 608 263 1589
Fax: +1 608 262 8464

Email: dbradley at engr.wisc.edu