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Re: [EnergyPlus_Support] Re: Ungodly number of errors



Brian,

The max iteration errors are lilely due to the air system being out of 
control. So ignore those
for the time being. You then very likely have 2 problems:

1) the DX coils are generating errors, probably due to the curves

2) The boilers aren't working correctly

Attack each of these separately. First the boilers - run one winter day 
with time step reports for
the boiler exit nodes and the 2 main air loop heating coil water and air 
inlet nodes. If the water temperatures
are below the air temperatures you will get the controller errors you 
are seeing. Then try to figure out why
the boilers are not heating the water properly. Try getting it to work 
with one boiler, minimum flow down
to zero. Make sure the boiler has enough capacity and hot water flow.

2nd the DX coils. Go back to the curves used in the example files, run 1 
summer day, and see what happens.
Then put in your curves - errors or not? BTW your max x and y values in 
the curves look frightening. There's
no way your curves would produce good results over that range. The range 
of these curves needs to be fairly
restricted.

Fred

Brian Streby wrote:
> Fred,
>    
>   I did my best to pore through the input and output files, but could not find any errors. I checked the .bnd file for nodes, branches, components, and particularly the parent and non-parent node connections. All appeared as I would have expected. Is there any chance one of you could help with the controller, psychrometrics, and SimHVAC: Maximum iteration errors? To help you more easily understand the systems involved, I have included sketches of the system topologies in the problem submittals/PSU-WB directory together with the input/output files.
>    
>   Thanks in advance.
>    
>   Regards,
>    
>   Brian
>
> Fred Buhl <wfbuhl@xxxxxxx> wrote:
>           Yes, the low temperature could cause the controller message. Typically 
> this would be a HW
> coil that is cooling or a ChW coil that is heating. It seems the problem 
> is in Plant.
>
> Fred Buhl
>
> brianstreby wrote:
>   
>> Just a quick follow-up to clarify-
>>
>> I'm pretty comfortable with the surface warnings in the error file. The 
>> errors that concern me include the following:
>>
>> ** Warning ** No valid range found for Loop Demand=726610.25 in Load 
>> Range Based Operation Scheme=BLR STAGING.
>> ** Severe ** Controller error for controller = RTU-2 HW COIL VALVE
>> ** Warning ** SimHVAC: Maximum iterations (20) exceeded for all HVAC 
>> loops 
>> ** Warning ** Branch flow rates out of bounds in FlowResolver
>>
>> I checked into the controller error and found nothing wrong with the 
>> controller setup. From the Boiler Report, it appears that the hot water 
>> temperatures are extremely low (i.e. < 10 deg C), which I suspect could 
>> cause a controller issue. Also, I have two boilers in parallel and set 
>> a minimum hot water loop flow rate of 80 gpm (2.52 kg/s) and use a load-
>> side bypass. From summer month data in the boiler report, it appears 
>> that the minimum loop flow was applied to each boiler, rather than the 
>> loop as a whole. In other words, I was expecting to see 40 gpm flow 
>> through each boiler in the summer but found that it was 80.
>>
>> Regards,
>>
>> Brian
>>
>> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "brianstreby" 
>> <brianstreby@...> wrote:
>>
>>     
>>> My simulation is running and I get results, however, my error output 
>>> file has an obscene amount of severe errors and warnings (and results 
>>> in the output spreadsheet are a bit whacky too). I found diagnosing 
>>> errors that occurred during the compiling stage fairly easy, but the 
>>> ones that appear during the simulation seem more obscure. I am not 
>>> quite sure where to begin... Any advice?
>>>
>>> I've uploaded my input/output to the .../_Problem_ Submittals/ PSU_WB 
>>> directory in .zip format with today's date.
>>>
>>>
>>>       
>>
>>
>> The primary EnergyPlus web site is found at:
>> http://www.energyplus.gov
>>
>> The group web site is:
>> http://groups.yahoo.com/group/EnergyPlus_Support/
>>
>> Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
>>
>> EnergyPlus Documentation is searchable. Open EPlusMainMenu.idf and press the "search" button.
>>
>> Yahoo! Groups Links
>>
>>
>>
>>
>>     
>
> [Non-text portions of this message have been removed]
>
>
>
>          
>
>  
> ---------------------------------
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> in the Yahoo! Answers Food & Drink Q&A.
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> [Non-text portions of this message have been removed]
>
>
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
> Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
>
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.idf and press the "search" button.
>  
> Yahoo! Groups Links
>
>
>
>   


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