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Re: [EnergyPlus_Support] Anomalous results with ** Warning ** GetAirPathData: & ** Warning ** WetBulb
Considering that the real system is not able to cool the zone and the real zone does not have a cooling sistem, I imagine that in summer the minimum temperature of the supply air should be always 18.
On Friday, June 6, 2014 4:02 PM, "Jean Marais jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
I'll ask a question:
If your zone requires cooling, what would be the coldest allowable temperature to supply it with?
2014-06-06 14:17 GMT+02:00 Marco Aldegheri <mailto:m.aldegheri@xxxxxxxxx>m.aldegheri@xxxxxxxxx [EnergyPlus_Support] <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx>:
>
You must forgive me but I don't totally follow you.
> That's of course because of my inexperience, so please, be patient.
What do you mean with Toda?
> I created the idf via DB and that's what I have.
The coil must heat the air exiting from the heat exchanger till 18°C. If the air temperature in input to the coil is 18 or warmer, the coil must be OFF. It's important to me that the airflow, exiting from the coil and pushed to the zone, has a temperature like the external outdoor air with a limit, it can't be lower than 18°C.
> With the suggested,
>
> SetpointManager:OutdoorAirReset,
> Air Loop Setpoint Manager, !- Name
> Temperature, !- Control Variable
> 18.00, !- Setpoint at Outdoor Low Temperature {C}
> 18.00, !- Outdoor Low Temperature {C}
> 7.00, !- Setpoint at Outdoor High Temperature {C}
> 18.01, !- Outdoor High Temperature {C}
> Air Loop Setpoint Manager Node List; !- Setpoint Node or NodeList Name
>
> I see that the temperature of the node, going up and up, in particular during summer time.
> This system is not properly an heating implant, it is only an air supplier with the ability to pump air in a zone warming it if needed.
>
>
> On Friday, June 6, 2014 10:40 AM, "Jean Marais <mailto:jeannieboef@xxxxxxxxx>jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>
>
>
when the Toda > 18, then the setpoint on the node changes to 16. the heating coil will activate to best reach the temperature of 16 with the warm incomming outdoor air, i.e. to best reach the new setpoint, it will turn off. However, if you also had a cooling coil, it too would try and reach the new setpoint, i.e. it would activate and try and reach 16. Perhaps you want the coldest supply air temperature to be also 18? So set 16 to 17.9. For your heating coil it must just be less than 18 to turn off the heating coil at Toda >18
>
>
> 2014-06-06 10:05 GMT+02:00 Marco Aldegheri <mailto:m.aldegheri@xxxxxxxxx>m.aldegheri@xxxxxxxxx [EnergyPlus_Support] <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx>:
>>
What do you mean with "Where 16 is the required temp at Toda>18..."?
I tried a run with those temperature but, shouldn't the temperature value in correspondence of the SYSTEM NODE TEMPERATURE, AIR LOOP AHU HEATING COIL AIR OUTLET be, more or less, 18°C if Tout<18 or = Tout is Tout>18?
Having a look to the heating coil air heating rate I see that it works only when the Tout is<18° so it seems correct. The point is that maybe I don't understand the temperature of node.
>>
>>
>> On Friday, June 6, 2014 6:42 AM, "'<mailto:jeannieboef@xxxxxxxxx>jeannieboef@xxxxxxxxx' <mailto:jeannieboef@xxxxxxxxx>jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>
>>
>>
Where 16 is the required temp at Toda>18...
>>> SetpointManager:OutdoorAirReset,
>>> Air Loop Setpoint Manager, !- Name
>>> Temperature, !- Control Variable
>>> 18.00, !- Setpoint at Outdoor Low Temperature {C}
>>> 18.00, !- Outdoor Low Temperature {C}
>>> 7.00, !- Setpoint at Outdoor High Temperature {C}
>>> 18.01, !- Outdoor High Temperature {C}
>>> Air Loop Setpoint Manager Node List; !- Setpoint Node or NodeList Name
>> Mit freundlichen Grü�en- Sent from my iPhone (excuse the brevity)
>> i. A.
Jean Marais
b.i.g. bechtold
Tel. +49 30 6706662-23
>> On 05.06.2014, at 22:20, "Marco Aldegheri <mailto:m.aldegheri@xxxxxxxxx>m.aldegheri@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>
>>>
Anyway, I should add some informations about the main topic.
>>>
>>> I still have problems with the air system.
>>> The air loop is composed by
>>> Outdoor air --> heat exchanger --> electric coil -->Zone -->heat exchanger--Outdoor
>>> The electric coil should increase the incoming air temperature to 18°C if the T outdoor is lower than 18°, than it should not heat the air flow if the external air is warmer than 18°C.
>>>
>>> Is it possible to reproduce this mechanism?
>>>
>>> I used the
>>>
>>> SetpointManager:OutdoorAirReset,
>>> Air Loop Setpoint Manager, !- Name
>>> Temperature, !- Control Variable
>>> 18.00, !- Setpoint at Outdoor Low Temperature {C}
>>> -20.00, !- Outdoor Low Temperature {C}
>>> 18.00, !- Setpoint at Outdoor High Temperature {C}
>>> 18.00, !- Outdoor High Temperature {C}
>>> Air Loop Setpoint Manager Node List; !- Setpoint Node or NodeList Name
>>>
>>> but I'm obtaining an unexpected result. If I look at the temperature of the air just after the coil
>>>
>>> Output:Variable,
>>> Air Loop AHU Heating Coil Air Outlet Node !- Key Value
>>> System Node Temperature, !- Variable Name
>>> Hourly; !- Reporting Frequency
>>>
>>> I can see the graph i'm uploading.
>>> As you can see the temperature is 18 only when the site outdoor temperature is very low, and it increases when the site outdoor temperature increases. It should not increase. The coil should not work where Tout>18°C
>>>
>>> I tried also a setpoint manager schedule with a schedule of 18°C for all time but the coil has a very very similar behaviur.
>>>
>>> Am I trying to do something impossible or there is a solution?
>>>
>>> Thanks,
>>> Marco
>>>
>>> On Thursday, June 5, 2014 9:50 PM, "Marco Aldegheri <mailto:m.aldegheri@xxxxxxxxx>m.aldegheri@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>>
>>>
>>>
Thanks, Jean.
It was my fault. I didn't realized that I was using a fake version of the weather file used by Db.
Forgive me, now it's ok.
>>>
>>> Marco
>>>
>>>
>>> On Thursday, June 5, 2014 9:27 AM, "<mailto:'jeannieboef@xxxxxxxxx>'jeannieboef@xxxxxxxxx' <mailto:jeannieboef@xxxxxxxxx>jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>>
>>>
>>>
If you don't have another machine to run it on, send me the idf privately.
>>>
>>> Mit freundlichen Grü�en- Sent from my iPhone (excuse the brevity)
>>> i. A.
Jean Marais
b.i.g. bechtold
Tel. +49 30 6706662-23
>>> On 04.06.2014, at 18:53, "Marco Aldegheri <mailto:m.aldegheri@xxxxxxxxx><mailto:m.aldegheri@xxxxxxxxx>m.aldegheri@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx><mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>>
>>>>
Uhmm it's very strage, the txt are just the same.
>>>>
>>>> I don't understand why it's happening so. Jean, please, could I ask you a courtesy?
>>>> Do you see any difference between the zone mean air temperature of the DB file and the idf processed by e+?
>>>> On my pc e+ shows me a non-sense.
>>>> Could you make a try? The file is very fast to run.
>>>>
>>>> Marco
>>>>
>>>>
>>>> On Tuesday, June 3, 2014 1:45 PM, "<mailto:'jeannieboef@xxxxxxxxx><mailto:'jeannieboef@xxxxxxxxx>'jeannieboef@xxxxxxxxx' <mailto:jeannieboef@xxxxxxxxx><mailto:jeannieboef@xxxxxxxxx>jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx><mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>>>
>>>>
>>>>
Hi Marco,
Do a text compare of the in.idf file located in the DesignBuilder energyplus folder, and the exported idf. They should be the same. If not, I would notify DesignBuilder via a helpdesk ticket. Let me know what you find.
Regards,
>>>>
>>>> Mit freundlichen Grü�en- Sent from my iPhone (excuse the brevity)
>>>> i. A.
Jean Marais
b.i.g. bechtold
Tel. +49 30 6706662-23
>>>> On 02.06.2014, at 16:55, "<mailto:m.aldegheri@xxxxxxxxx><mailto:m.aldegheri@xxxxxxxxx><mailto:m.aldegheri@xxxxxxxxx>m.aldegheri@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx><mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx><mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>>>
>>>>>
Hi all,
>>>>>
>>>>> I'm testing an air heating system on a minimodel.
>>>>> I created it with DesignBuilder and in DB I obtained an apparently correct internal temperature vs time.
>>>>> Than I explorted the idf and I processed the idf (no modified, of course) with E+. The zone mean air temperature now is completely different and in my opinion completely out of mind.
>>>>>
>>>>> The heating system just takes the air from the outside and heat the flux untill 18°c if the air temperature is lower than this value.
>>>>>
>>>>> In particular I have 2 suspicious warnings, they are:
>>>>>
>>>>> ************* Beginning System Sizing Calculations
>>>>> ** Warning ** GetAirPathData: AirLoopHVAC="AIR LOOP" has no Controllers.
>>>>>
>>>>> and
>>>>>
>>>>> ************* Beginning Simulation
>>>>> ** Warning ** WetBulb not converged after 101 iterations(PsyTwbFnTdbWPb)
>>>>> ** ~~~ ** Routine=Unknown, Environment=UNTITLED, at Simulation time=03/28 15:00 - 15:06
>>>>> ** ~~~ ** Input Temperature = 18.50
>>>>> ** ~~~ ** Input Humidity Ratio= 0.141212
>>>>> ** ~~~ ** Input Pressure = 99122.00
>>>>> ** ~~~ ** Resultant Temperature= 25.44
>>>>>
>>>>> Thanks,
>>>>> Marco
>>>>> <PROVA VENT.rar>
>>>>
>>>
>>>
>>>
>>>
>>> <IMG1.png>
>>> <IMG2.png>
>>> <IMG3.png>
>>> <EDIFICIO IMPIANTO CORRETTO.idf>
>>
>
>
>
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Posted by: Marco Aldegheri <m.aldegheri@xxxxxxxxx>
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