[TRNSYS-users] trnsys 17 do not achieve the same results of trnsys 15 ?

[David BRADLEY]

Eunice,
  I would recommend that you change from using Type109 to using Type15 
(unless you are using the "user format data" mode in type109. If you are 
using a meteonorm data file, change to Type15) since type15 computes and 
reports the ground reflectance. If you want to keep using Type109, use a 
value of 0.2 for non-snow covered locations and a value of 0.7 when you 
think there might likely be snow covering the ground
Kind regards,
  david


On 5/3/2012 10:37, dec07001 wrote:
> Dear Mr. Bradley
>
> Thanks for your answer.
> Since I do not have values for the GRDREF what do you advise to use.
> Best regards
> Eunice
>
>
>
>
> Em 03.05.2012 16:12, David BRADLEY escreveu:
>> Eunice,
>>  I would not expect to obtain the same results from a Trnsys15 and
>> Trnsys17 simulation; we are continually trying to improve on the
>> models and to incorporate new algorithms so as to keep on top of best
>> modeling practices. In your email, you point out one possible
>> explanation for the difference in that the Trnsys17 building model
>> considers radiation exchange not only between the building walls and
>> the sky but also now between building walls and the ground.
>> Kind regards,
>>  david
>>
>>
>> On 5/3/2012 07:55, dec07001 wrote:
>>> Dear all
>>>
>>> I used trnsys 15 to simulate de heating and cooling needs of a 8 
>>> zone building (2 zones/ 4 levels) and now a I am using trnsys 17 and 
>>> not achieving the same results for the exact same building (it 
>>> varies from 5 to 20% more demanding) is this possible?
>>>
>>> Conditions considered:
>>> 1-exactly the same constructive solution and windows
>>> 2-exactly the same simulation components (types:9, 16i, 69b ,33e, 56 
>>> and 25)
>>> 3-for 4 the new inputs in type 56:
>>> type 16i provide the AZEN and AAZM
>>> the TSGRD considered equal to TAMB
>>> and GRDREF left to link
>>> 4-the heating and cooling needs previously obtained in the demands 
>>> file of the trnsys 15, are now beenig obtain (trnsys 17) with the 
>>> NTypes 1, 30 and 31.
>>>
>>> All help will be appreciated, thanks
>>> Eunice Fontao
>>>
>>> _______________________________________________
>>> 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
>
>

-- 
***************************
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