[TRNSYS-users] "Average value over time step" in TRNSYS Types

[Jeff Thornton]

<If I solve the model equation for the time  t(i-1/2), would this be a
correct approach to find Tavg? I can then solve for both Tavg and Tf, and
use Tf as Ti in the next time step. Is this how it's done in the
standard/TESS TRNSYS components? >

No - in the TRNSYS components that have mass we solve for the average
temperature over the timestep and don't approximate it with a linear
solution or a solution at the midpoint of the timestep.

Take your solution for the temperature and integrate it over the timestep
and then divide by the timestep to get the average value.  Refer to the
Programmers guide in the section for differential equations for a more
detailed explanation when you have a simple linear DiffEq.

Jeff


Jeff Thornton
President - TESS, LLC

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