[TRNSYS-users] Changing thermal capacity of type 56 DURING a simulation?

[David BRADLEY]

Jochen,
   I do not think that there is a way of changing the zone capacitance 
during a simulation. There is a model for a lumped capacitance in the 
TESS Loads and Structures library that could be a starting point model 
for writing your own model of the product being stored. Two challenges 
occur to me though: first, I would be surprised if you could model the 
stored product with the "lumped capacitance" assumption. That assumption 
basically means that there is no temperature gradient within the product 
(that its internal thermal conductivity is high in comparison to its 
surface heat transfer). Second, it also assumes that the capacitance 
does not change. I think the only really correct solution would be to 
solve the differential equation (including the change in mass (dm/dt) 
and then code it as a Type. Type56 would pass it the surrounding zone 
air temperature and your model would compute the amount of energy 
transferred to/from the zone, passing that back as an input to Type56.
Best,
  David


On 1/4/2012 05:58, Jochen Doell wrote:
> Dear TRNSYS-developpers & users,
>
> is there a way to change the thermal capacity of type 56 DURING a 
> simulation?
>
> We need to simulate a storage room which can be filled at different 
> levels.
> We already thought about an external calculation but would prefer 
> easier methods if available.
>
> Best regards (and happy new year, for the very late risers),
> Jochen
>

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
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d.bradley at tess-inc.com

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