[TRNSYS-users] Piping thermal capacitance

[Jeff Thornton]

Marco, 

Simply include pipes in your system and choose a pipe model
that takes into account not only the thermal capacitance of the fluid
but also that of the the pipe wall and insulation. As a nice
approximation, you can also create one pipe that has the same volume as
the volume of all the pipes that lead to the collectors and the same
surface area as the surface area of all the pipes that lead to the
collector. With a bit of work, you can also calculate the effective
insulation thickness that gives you the same thermal resistance. Repeat
the process for the pipes returning from the collector array. 

Jeff


---

Jeff Thornton 

_President - TESS LLC_ 

_22 N. Carroll Street,
Madison WI USA 53703_ 

_Office: (608) 274-2577 Fax: (608) 278-1475_


_www.tess-inc.com_ 

_E-Mail: thornton at tess-inc.com_ 

On 10/10/2012
7:34 am, Marco Scarpellino wrote: 

> Dear all,
> 
> I am trying to
simulate with TRNSYS a solar cooling system.
> I am not able to simulate
the thermal capacitance of the piping of the plant. I try to explain
better what I mean: in the early morning, in the real condition, the
pipe has a temperature equal to the ambient temperature, because of the
stop of the plant during nighttime and the consequent temperature
decrease. When the pump starts to run and the panels begin to work the
temperature of the piping rises until it reaches the fluid working
temperature. The energy that we produce with the solar thermal panels in
the meantime is used to raise the temperature of the whole piping. How I
can take into account this loss of energy?
> 
> I am at your disposal
for any clarification you may need.
> 
> Thanks in advance for your
help.
> 
> Best Regards,
> 
> Marco Scarpellino
 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/trnsys-users-onebuilding.org/attachments/20121010/e72bb4cc/attachment-0005.htm>