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



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

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--
***************************
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@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@tess-inc.com

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