[TRNSYS-users] Capacitance in TRNBuild

[David BRADLEY]

Ole,
   The conduction transfer function method (which takes into account the 
capacitance of the walls) is used for walls, ceilings, roofs, floors, 
etc. It is not used for the windows nor their frames. I don't think that 
the Type56 window model attributes any thermal capacitance to the 
windows or window frames.
best,
  David


On 2/27/2015 08:29, Ole Nienaber wrote:
> David,
> thanks for the advice. But can I take e.g. windows into account with 
> these models? Now I model my whole geometric zone with Google SketchUp 
> using the Trnsys3d plug-in.
> Greets,
> Ole
>
> Am 24.02.2015 um 17:51 schrieb David BRADLEY:
>> Ole,
>>  To add to what Jean Marais said, by including the wall capacitance 
>> in the zone and making only resistive walls you are turning Type56 
>> into something resembling a lumped capacitance model and are no 
>> longer taking advantage of there being any difference between the air 
>> temperature and the surface temperatures. If that is the kind of 
>> model that you want to use then there are some actual lumped 
>> capacitance building models either as a single zone model the 
>> standard library (Type88) or as a multizone model in the TESS Loads 
>> and Structures library (Types 759 and 660)
>> best,
>>  David
>>
>>
>>
>> On 2/22/2015 06:01, Ole Nienaber wrote:
>>> Dear all,
>>>
>>> I'm trying to model a building zone in TRNBuild. The store capacity 
>>> is specified by 90 Wh/(m²*K). Unfortunately there is no information 
>>> about the single store capacities (e.g. walls, furniture,...). Now 
>>> my idea was to just model the zone with massless walls and to add 
>>> the whole store capacity to the capacity in TRNBuild (normally the 
>>> wall capacity is not valued in this parameter). Normally I don't see 
>>> any problems regarding to this way of calculation, becauce I only 
>>> use the absolute value of the capacity. Do you see any problems in 
>>> doing this?
>>>
>>> Thanks and greets,
>>> Ole
>>> _______________________________________________
>>> TRNSYS-users mailing list
>>> TRNSYS-users at lists.onebuilding.org
>>> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org
>>
>
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

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d.bradley at tess-inc.com

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