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Re: [EnergyPlus_Support] Detailed Ice Storage system warning





Jeremiah,

Could you share your input file? (I'm interested in seeing how ice storage is modeled as I'll have to do it soon)

Otherwise, when in detailed warning output mode, what does it say? 

Maximum iteration, I think, means it didn't converge, but that doesn't mean an "acceptable" (per real life) solution hasn't been found, just that it wasn't within the boundaries you set (could be crazy, could be just outside the boundary)

I had the same problem with a complicated data center model but the results made sense.

Best,
Julien

Envoyé de mon iPhone

Le 8 août 2014 à 21:06, "Jeremiah Crossett jcrossett@xxxxxxxxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> a écrit :

 

Dear List,

I am modeling an existing building with a 20 ton chiller and 82 ton hour latent energy storage system that uses our bio based PCM as a replacement for ice. We expect that using a higher melting temperature will save energy consumption compared to ice and enable retrofit scenarios that would not be possible with the sub zero supply temperatures.  To model this I have set the transition temperature to 5.5C, and nighttime charge temperature from chiller supply loop at 2.2C.  
For comparison I have also made the same model with ICE.  I used the charge and discharge curves from ICE in the PCM storage tank model.  

The problem I am hopeful you could help me to better understand is the recurring warning pasted below.   I think it is saying that I have caused model instabilities. 
I am wondering if anyone has any suggestions for how I might change the model to not produce this warning / instability? --->Thanks  

   **   ~~~   **  Environment=ANNUAL, at Simulation time=01/03 17:30 - 17:40
   ** Warning ** Detailed Ice Storage model exceeded its internal discharging maximum iteration limit
   **   ~~~   ** Detailed Ice Storage System Name = LESS TANK
   **   ~~~   **  Environment=ANNUAL, at Simulation time=01/03 17:30 - 17:40

   ************* ===== Recurring Error Summary =====
   ************* The following recurring error messages occurred.
   *************
   *************  ** Warning ** Detailed Ice Storage system [LESS TANK]  discharging maximum iteration limit exceeded occurrence continues.
   *************  **   ~~~   **   This error occurred 29163 total times;
   *************  **   ~~~   **   during Warmup 0 times;
   *************  **   ~~~   **   during Sizing 0 times.


​​
Jeremiah D. Crossett
 
 | Senior Analyst  LEED Green Associate 
​​
120 E. Pritchard St.  | Asheboro, NC 27203 
​​
 | Mobile 503-688-8951
  



<Q0_82TnHrLESS_20TonChillerUpstream.idf>
<Q5_82TnHrLESS_20TonChillerUpstream.idf>


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Posted by: Julien Marrec <julien.marrec@xxxxxxxxx>


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