[TRNSYS-users] Behaviour of water pipes

Diego A. Arias daarias at wisc.edu
Tue Nov 1 13:45:55 PST 2005

Dear Xavier:

Type 31 (pipe or duct) calculates the thermal losses in a pipe, using a 
plug-flow model.  This component is based on the solution of an energy 
balance equation for the pipe.  One of the parameters of this component 
is the heat transfer coefficient for thermal losses to the environment, 
based on the inside pipe surface area.  You have to calculate this value 
for the different insulation strategies.  The outputs are the outlet 
fluid temperature and the different energy rates: losses to the 
environment, inlet energy to the pipe, change in internal energy.  
Please refer to section 5.6.4 of the Volume 5 for a description of the 
mathematical model.

Please let me know if you have additional questions.
Best regards,


Xavier Dequaire wrote:

>HI all,
>I wonder if I can easily make a model of the following configuration:
>a water system for a residential building
>with DHW
>A tank for DHW at given temperature
>(further developement is thermosyphon solar heater on roof)
>Hot water pipe
>Cold water pipe
>Place of use and mixing
>The idea is to compare
>different piping lay-outs
>the impact of the distance from storage to use( length of pipes)
>the impact of pipe insulation
>The backgroung is the obvious discomfort to get hot water delivered at
>first outdoor temperature, then maximum tank temperature around 70-80C,
>then mixit etc.. and the thermal losses related ( in a low energy
>building, the DHW energy consumption gets a high % of total energy
>Any hint experience out there?
>thank you
>TRNSYS-users mailing list
>TRNSYS-users at engr.wisc.edu


Diego A. Arias
TRNSYS Coordinator
Solar Energy Laboratory
University of Wisconsin - Madison
1500 Engineering Drive
Madison, WI 53706

More information about the TRNSYS-users mailing list