I have solved the problem by reducing the number of terminal units. Before I had 4 TU in one single zone, and this caused many warnings. Now I have placed only 1 TU with the equivalent capacity o the 4 units, and the warnings are gone. But it would be good to be able to insert more than 1 TU per thermal zone. In the meantime I will leave it like this.
Santiago
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jim Dirkes" <jim@...> wrote:
>
> Santiago,
>
> I am guessing, but I think that "iteration limit exceeded" warnings occur
> when the system heating / cooling capacity is not great enough and also when
> air flow is not balanced between supply and exhaust.
>
> In your example, the load is less than zero, indicating a need for heating
> (-0.12331), but the system is still cooling (although at a very small rate;
> 3.54534E-016). Perhaps this is a cooling-only system? Or several zones are
> included with one system and one of them calls for heating while the others
> need cooling?
>
>
>
> The Building Performance Team
> James V. Dirkes II, P.E., BEMP , LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
>
>
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of iluminasol33
> Sent: Friday, March 02, 2012 7:00 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] HVAC Terminal Unit: VariableRefrigerantFlow
>
>
>
>
>
> Dear Forum,
>
> I started to model the VRV HVAC Terminal Unit, and I have received many
> warnings as this one:
>
> Warning ** ZoneHVAC:TerminalUnit:VariableRefrigerantFlow "TU2 COMEDOR"
> ** ~~~ ** Iteration limit exceeded calculating terminal unit part-load
> ratio, maximum iterations = 500
> ** ~~~ ** Part-load ratio returned = 6.291E-003 Environment=NESTLE CHIAPA DE
> CORZO, at Simulation time=01/02 06:00 - 06:10
> ** ~~~ ** Load requested = -0.12331, Load delivered = 3.54534E-016
>
> I do not know the reason of it, but I think it is necessary to solve it in
> order to trust the results of the simulation.
>
> Any advice greatly appreciated!
>
__._,_.___