[TRNSYS-users] Quick question on solar collector model

[David BRADLEY]

Dev,
   The thermal losses from a collector are computed based on a 
temperature difference between the fluid and the ambient. There are a 
number of different standards, however. Some base these losses on the 
difference between the inlet fluid temperature and the ambient while 
others use a mean fluid temperature. In order to get a more accurate 
estimate of the losses, Type536 breaks up the fluid flowing through the 
collector into a series of nodes, each of which is assumed to be 
isothermal and each of whose energy balance is represented by a 
differential equation. The higher the number of nodes the more accurate 
the temperature profile of liquid flowing through the collector. As you 
increase the number of nodes the outlet temperature should change less 
and less.
Kind regards,
  David


On 3/6/2014 08:05, dev sharma wrote:
>
> Hey All,
>
> Can someone please tell me the physical significance of No. of Nodes 
> in modelling a solar thermal collector? or how is T_out dependent on it?
>
> My observation by running the model is that T_out increases with 
> increase in number of nodes, but the effect is such that T_out is 
> dependent on the exponential of this number somehow. Am I even close 
> to making sense?
>
> Thanks
>
> Dev Sharma
>
>
>
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
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P:+1.608.274.2577
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d.bradley at tess-inc.com

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