Re: [TRNSYS-users] Trnsys iteration and converge problems

[a8304506@graduate.hku.hk]

Hello, Siren.

Try adding some thermal mass in the water circuit by using Type31.  This should
help improve the iteration stability.

Best Regards
C.K. Lee
University of Hong Kong


Quoting Santeri Siren <santeri.siren1@gmail.com>:

> Dear Trnsys users,
> 
>  it seems that Trnsys has iteration problems in my simulation project. Some
> values do not converge as they should.
> 
> *Description of my project:*
> 
> I have a Trnsys simulation project where I have created a closed flow
> circuit that models a chiller equipped cooling system. Return water flows
> from the load to the chiller which is set to cool it to 7 C. The water flow
> rate in the circuit varies significantly over time. A variable speed pump
> is used to create the variations in the water flow.
> 
> 
> *Description of the problem:*
> 
> Problems occur every time when the water flow rate changes rapidly from a
> very small value to a relatively much larger value. In this case the
> chiller power water temperatures suddendly jump to infinite.
> I belive that Trnsys has problems in the iteration prosess so that the
> values do not converge. I have tried to modify some of the basic options in
> the control cards, e.g. solution method and simulations time step but it
> didnt help. This problem is not in my area of expertise and I really dont
> know how to fix this. Could some one please help me with this matter?
> 
> Best regards.
> 
> Santeri Siren
>