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

[David Bradley]

Knut Erik,
 Sorry for the delay in getting back to you. Since almost all of the 
outputs that TRNSYS deals with are averages over the timestep, the input 
values that are passed to your components are the averages at the 
previous timestep and so your component doesn't really have to compute 
what those values are. If your component has some capacitance (thermal 
or electrical storage) to it then you do need to get what the value of 
certain inputs at the end of the last timestep were in order to 
calculate what the outputs at the end of the current timestep are. One 
typical way of handling the job of keeping track of those is to use the 
"getStorageVars()" and "setStorageVars()" subroutines. If you have to 
call the Differential Equation subroutine from within your Type, it will 
return the average and final value for the time step. You can then store 
that final value and use it as the initial value for the next time step.
Kind regards,
 David


knut.erik.enerstvedt at niva.no wrote:
>
> Hello TRNSYS users,
>
>  
>
> As I understand, TRNSYS outputs are averaged values over a time step, 
> meaning that the output value of T at timestep n is an average of T 
> between n-1 and n. When creating a new Type, would it be correct of me 
> to have T_output(n) = (T(n) + T(n-1))/2, where T(n) is the newly 
> computed value in the current iteration and time step and T(n-1) is 
> the converged value from the previous time step? If not, how is this 
> average normally computed in TRNSYS Types?
>
>  
>
> Best regards,
>
> Knut Erik Enerstvedt
>
>
>
> ------------------------------------------------------------------------------------------------------
>
> Meld deg på vårt nyhetsbrev på www.niva.no
>
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>
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