[TRNSYS-users] TRNSYS and BESTEST validation

[David BRADLEY]

Dapeng,
   While BESTEST (and ASHRAE Standard 140 - which is identical to 
BESTEST) try hard to be very clear about what assumptions you should 
make in each of the test cases, there is still /a lot/ of room for 
interpretation. Some years ago, we ran TRNSYS 16.1 through those test 
cases as well and found that you can make quite legitimate 
interpretations of the standard and come out with quite a variety of 
results. I would recommend you have a look at a couple papers that we 
wrote about the effort:

"Converging on a Recommended Set of Interpretations and Assumptions in 
Applying Standard Tests to Energy Analysis Tools"
"Experiences with and Interpretations of Standard Test Methods of 
Building Energy Analysis Tools"

both are available at http://www.tess-inc.com/pubs.

If my recollection is correct, we were within the range on the 600 
cases. If anything, the annual cooling that modern versions of TRNSYS 
predict is on the low end of the range and is sometimes below the range. 
It is worth keeping in mind that the "acceptable range" of results does 
not come from an analytical solution. It comes from the results 
generated by a bunch of software tools and TRNSYS (version 13!) is one 
of them. Other software developers have mentioned to me recently that 
building science and cooling load algorithms have advanced since the 
1980s and that more recent algorithms do predict lower cooling loads 
than did the older algorithms. This is not reflected in the BESTEST or 
Standard140 results; those ranges are still set by the older versions of 
the tools.

Best,
  David


On 11/14/2011 21:14, Dapeng Li wrote:
>
> Dear all users,
> Hello.
>
> I try to take a test by using BESTEST algorithm. I use TRNSYS version 
> 16.01.003. I think I have taken my best to set up each parameters in 
> TRNSYS's deck and TRNBUILD according to case 600's condition in the 
> BESTEST documents which is downloaded from 
> _http://www.nrel.gov/docs/legosti/old/6231.pdf?_But the annual heating 
> load (5.997MWh) from TRNSYS is different from the value ranges (4.296 
> to 5.709). The annual cooling load (6.519MWh) fit well. I wonder the 
> reasons of this kind of difference. For convenience, I attached my 
> project for your deep examine.
>
> Thank you for your help in advance.
>
> kindly regards,
> Dapeng Li
>
>
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at cae.wisc.edu
> https://mailman.cae.wisc.edu/listinfo/trnsys-users

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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