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RE: [EnergyPlus_Support] Re: Small School - Modelling Simple Heating and Ventilation Equipment
I have looked at your file some, but I haven't had time to really fix it or narrow down the issues.
Here are the problems I have found so far. The HVAC system is not setup to control the zones properly, only to blow 20C air into the zones. If you want the zone's temperature controlled to 20C, you'll need supply air that is warmer than 20C. Because there is no temperature difference between supply and setpoint, the autosizing results are way off the charts (eg. direct air rates of over 1000 m3/s). This is really difficult to verify but I suspect that the errors you are getting are the because of numerical difficulties in the HVAC component models that stem for too large of design values. If you really want the direct air terminals to just provide neutral 20C air into the zones, then you will need to manually size the system.
If you are expecting the direct air to control the zone, then choose reasonable numbers for supply air temperatures (eg. 40C) in the system and sizing input. You need to use set point manager such as 'Set Point Manager:SingleZone Heating" rather than a Scheduled so it can control the temperature of the inlet. Also each of your air loops serves 2 zones with direct air rather than using multizone terminal units. So one zone will have to be a slave and may not control well.
________________________________
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Nuno Costa Brandão
Sent: Friday, February 15, 2008 9:20 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: Small School - Modelling Simple Heating and Ventilation Equipment
Dear Group Supporters,
I´m reposting the last post, hoping to get an answer. Unfortunately
I´m still not able to do any "real work" before clarifying the doubts
regarding this simple model.
Thanks for the help
Nuno
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx <mailto:EnergyPlus_Support%40yahoogroups.com> , Nuno Costa Brandão
<ncostab@...> wrote:
>
> Hi
>
> I changed the modelling solution for this building, to a two air loop
> possibility using direct air. I corrected the issues discussed above,
> tried a small period simulation (january month), but it resulted in
> some severe errors. I looked at the issues suggested in the error
> report but I don´t think the problem is related to these suggestions.
> Could it be the HVAC system modelling? The errors are as follow:
>
> Program Version,EnergyPlus 2.1.0.023, 11-02-2008 16:13,IDD_Version
> 2.1.0.023
> ************* Beginning Zone Sizing Calculations
> ** Warning ** Weather file location will be used rather than
> entered Location object.
> ** ~~~ ** ..Location object=FAMALICAO
> ** ~~~ ** ..Weather File Location=PORTO - PRT IWEC DATA
WMO#=085450
> ** Warning ** Calculated design cooling load for zone=EDÍFICIO -
> SALA AULA 3 is zero.
> ** ~~~ ** Check ZONE SIZING and ZONE CONTROL:THERMOSTATIC inputs.
> ** Warning ** Calculated design cooling load for zone=EDÍFICIO -
> SALA EDUCADOR is zero.
> ** ~~~ ** Check ZONE SIZING and ZONE CONTROL:THERMOSTATIC inputs.
> ** Warning ** Calculated design cooling load for zone=EDÍFICIO -
> SALA AULA 2 is zero.
> ** ~~~ ** Check ZONE SIZING and ZONE CONTROL:THERMOSTATIC inputs.
> ** Warning ** Calculated design cooling load for zone=EDÍFICIO -
> SALA AULA 1 is zero.
> ** ~~~ ** Check ZONE SIZING and ZONE CONTROL:THERMOSTATIC inputs.
> ************* Beginning System Sizing Calculations
> ** Warning ** Calculated cooling design air flow rate for
> system=AIR LOOP2 is zero.
> ** ~~~ ** Check ZONE SIZING and ZONE CONTROL:THERMOSTATIC inputs.
> ** Warning ** Calculated cooling design air flow rate for
> system=AIR LOOP1 is zero.
> ** ~~~ ** Check ZONE SIZING and ZONE CONTROL:THERMOSTATIC inputs.
> ************* Beginning Plant Sizing Calculations
> ************* Testing Individual Branch Integrity
> ************* All Branches passed integrity testing
> ************* Testing Individual Supply Air Path Integrity
> ************* All Supply Air Paths passed integrity testing
> ************* Testing Individual Return Air Path Integrity
> ************* All Return Air Paths passed integrity testing
> ************* No node connection errors were found.
> ** Warning ** Inside surface heat balance did not converge with Max
> Temp Difference [C] =2.493E-003 vs Max Allowed Temp Diff [C] =2.000E-003
> ** ~~~ ** Occurrence info=PORTO - PRT IWEC DATA WMO#=085450,
> 01/03 14:30 - 14:31
> ** Warning ** Inside surface heat balance did not converge with Max
> Temp Difference [C] =9.556E-003 vs Max Allowed Temp Diff [C] =2.000E-003
> ** ~~~ ** Occurrence info=PORTO - PRT IWEC DATA WMO#=085450,
> 01/03 14:45 - 14:46
> ** Warning ** Inside surface heat balance did not converge with Max
> Temp Difference [C] =9.928E-002 vs Max Allowed Temp Diff [C] =2.000E-003
> ** ~~~ ** Occurrence info=PORTO - PRT IWEC DATA WMO#=085450,
> 01/03 15:00 - 15:01
> ** Warning ** Inside surface heat balance did not converge with Max
> Temp Difference [C] =0.824 vs Max Allowed Temp Diff [C] =2.000E-003
> ** ~~~ ** Occurrence info=PORTO - PRT IWEC DATA WMO#=085450,
> 01/03 15:15 - 15:16
> ** Warning ** Inside surface heat balance did not converge with Max
> Temp Difference [C] =246.544 vs Max Allowed Temp Diff [C] =2.000E-003
> ** ~~~ ** Occurrence info=PORTO - PRT IWEC DATA WMO#=085450,
> 01/03 15:30 - 15:31
> ** Warning ** Temperature out of range [-100. to 200.]
(PsyPsatFnTemp)
> ** ~~~ ** CorrectZoneHumRat Occurrence info=PORTO - PRT IWEC
> DATA WMO#=085450, 01/03 15:16 - 15:17
> ** ~~~ ** Input Temperature=200.06
> ** Warning ** Temperature out of range [-100. to 200.]
(PsyPsatFnTemp)
> ** ~~~ ** CorrectZoneAirTemp Occurrence info=PORTO - PRT IWEC
> DATA WMO#=085450, 01/03 15:16 - 15:17
> ** ~~~ ** Input Temperature=200.06
> ** Warning ** Temperature out of range [-100. to 200.]
(PsyPsatFnTemp)
> ** ~~~ ** CorrectZoneHumRat Occurrence info=PORTO - PRT IWEC
> DATA WMO#=085450, 01/03 15:17 - 15:18
> ** ~~~ ** Input Temperature=200.34
> ** Warning ** Temperature out of range [-100. to 200.]
(PsyPsatFnTemp)
> ** ~~~ ** CorrectZoneAirTemp Occurrence info=PORTO - PRT IWEC
> DATA WMO#=085450, 01/03 15:17 - 15:18
> ** ~~~ ** Input Temperature=200.34
> ** Warning ** Temperature out of range [-100. to 200.]
(PsyPsatFnTemp)
> ** ~~~ ** CorrectZoneHumRat Occurrence info=PORTO - PRT IWEC
> DATA WMO#=085450, 01/03 15:17 - 15:18
> ** ~~~ ** Input Temperature=200.27
> ** Warning ** Temperature out of range [-100. to 200.]
(PsyPsatFnTemp)
> ** ~~~ ** CorrectZoneAirTemp Occurrence info=PORTO - PRT IWEC
> DATA WMO#=085450, 01/03 15:17 - 15:18
> ** ~~~ ** Input Temperature=200.27
> ** Warning ** Inside surface heat balance did not converge with Max
> Temp Difference [C] =264.266 vs Max Allowed Temp Diff [C] =2.000E-003
> ** ~~~ ** Occurrence info=PORTO - PRT IWEC DATA WMO#=085450,
> 01/03 15:45 - 15:46
> ** Severe ** Temperature out of bounds (-102.22) for surface=R_
> EDÍFICIO - SALA AULA 3_1_0_0
> ** ~~~ ** in Zone=EDÍFICIO - SALA AULA 3
> ** ~~~ ** Occurrence info=PORTO - PRT IWEC DATA WMO#=085450,
> 01/03 16:00 - 16:01
> ** ~~~ ** A temperature out of bounds problem can be caused by
> several things. The user
> ** ~~~ ** should check the weather environment, the level of
> internal gains with respect
> ** ~~~ ** to the zone, and the thermal properties of their
> materials among other things.
> ** ~~~ ** A common cause is a building with no thermal mass --
> all materials with
> ** ~~~ ** Regular-R definitions.
> ** Fatal ** EnergyPlus has exited due to the reason stated above
> ...Summary of Errors that led to program termination:
> ..... Reference severe error count=1
> ..... Last severe error=Temperature out of bounds (-102.22) for
> surface=R_ EDÍFICIO - SALA AULA 3_1_0_0
> ************* EnergyPlus Terminated--Fatal Error Detected. 19
> Warning; 1 Severe Errors; Elapsed Time=00hr 00min 7.17sec
>
> I´m uploanding the file so that you can have a look at it.
>
> Thanks for the help
> Nuno Brandão
>
[Non-text portions of this message have been removed]
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