Re: [EnergyPlus_Support] Re: \[EnergyPlus_Support\] Outlet and Inlet differ by more than tolerance\?

[Edwin Lee <leeed2001@xxxxxxxxx>]

YunPeng:

I took your 3.0 input file and converted it to 4.0.  After running it, I looked at the diagram of the HVAC loops, and there are a couple things that look odd to me, but the chilled water loop itself seems to be setup OK.

I debugged a bit, and may have come across a bug in the chiller simulation.  You see, the pump is trying to run, even though it seems the loop doesn't have demand.  This shouldn't be happening because the pump is set to Intermittent, but regardless it is.  When this occurs, the chiller doesn't have any demand, and so the flow from the pump should just pass through the chiller and out the outlet of the loop.  However, the chiller is cutting off the flow.  Thus the pump is pushing flow, but the chiller is turning it off.  

I am concerned that some of the air loop/coil configurations could be causing this odd behavior of flow request and components turned off, as the coils interact with the demand side of the loop. Two recommendations for now:

1: Add a bypass to the plant loop supply side to allow this excess flow to go down that path.

2: Investigate the coil/air loops setup a bit more to make sure the configurations are allowed.  I'll look into this as well, but I am not as familiar over there as I am with the plant simulation.

In the meantime, I'll file this is a bug in the chiller and investigate a little further how to catch and provide error support for this situation.

Thanks,
Edwin Lee

On Sat, Dec 19, 2009 at 14:17, Edwin Lee <leeed2001@xxxxxxxxx> wrote:

YunPeng:

Would you be able to post the input file causing this error?  Or post the file to a Helpdesk ticket maybe?  I'd like to have a look and see if I could find the problem for you.

Thanks,

Edwin Lee

EnergyPlus Development Team

On Sat, Dec 19, 2009 at 04:07, Y.P.Hu <hyp@xxxxxxxxxxxxxxxxx> wrote:

 

thank you dashamir, I'll try it!

dashamir marini å??é??:
>
>
> Hello
>
> From first view of Warning message seems that mass flow rate among out
> and in node at PlantSupplySide exceed tolerance value which you have
> input in your idf file. That means some leakage may have occured in
> demand side (distribution system or zone equipments) of your system.
> Usually this happen for air system flow, and I'm not sure if it can
> happen for water flow too.
> One my suggestion would be: try to increase tolerance value just to
> understand if this warning will occure more of course without
> exceeding limit values. If happen again try to check control objects
> in idf file.
>
> that is my opinion
>
> good luck
>
> Dashamir
>
>

--
ã??Give my best wishes to you!
Respectfully yours, YunPeng Hu
Huazhong University of Science and Technology
Wuhan, Hubei, China
hyp@xxxxxxxxxxxxxxxxx
hyp6789@xxxxxxx

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