[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [EnergyPlus_Support] Design coil load is zero
Hi,
I' m using the EnergyPlus 1.4.0.025 version. Could it be an issue related to
this program version?
One more question related to this topic: If I define an Outside Air flow
rate which will be supplied by the air loop, will it be accounted in zone
sizing? I'm asking this because I didn't define a central heating coil.
Thanks in advance
Filipe Madureira
Tel: +351 919 293 876 | E-mail: filipe.madureira@xxxxxxxxxxxxx
__________________________________________________________________
FluidInova, Engenharia de Fluidos, SA
TECMAIA - Parque de Ciência e Tecnologia da Maia
Rua Engº Frederico Ulrich, nº 2650 | 4470-605 Moreira da Maia | Portugal
Tel: (351) 229 408 265 | Fax: (351) 229 408 266
E-mail: geral@xxxxxxxxxxxxx | Web: http://www.fluidinova.pt/
-----Original Message-----
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Fred Buhl
Sent: 20 November 2007 20:49
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Design coil load is zero
Filipe,
What version of the program are you running?
Fred Buhl
Filipe madureira wrote:
> Hi all,
>
>
>
> I?m trying to simulate a Constant Volume Air Handling Unit to control
> temperature in a single zone. The AHU has a constant volume fan and a
> cooling coil. Heating is provided by a terminal reheat coil.
>
> To control the exit cooling coil air temperature I?ve defined a
> controller:simple and a Set - point manager: Warmest to reset the cooling
> coil air temperature.
>
> To control zone temperature, I?ve defined a dual set-point with deadband
> thermostat (heating set-point temperature 20ªC, cooling set-point
> temperature 24ºC).
>
>
>
> The total air system and outside air volumetric flow rates are known.
For
> this reason, in the zone sizing object I?ve defined the cooling and
heating
> design air flow method to ?flow/zone? and input the desired flow rates.
I?ve
> defined also the outside air flow rate.
>
>
>
> ZONE SIZING,
>
> P1 - Sala_Cirurgia, !- Name of a zone
>
> 16, !- Zone cooling design supply air temperature
> {C}
>
> 25, !- Zone heating design supply air temperature
> {C}
>
> 0.008, !- Zone cooling design supply air humidity
> ratio {kg-H2O/kg-air}
>
> 0.008, !- Zone heating design supply air humidity
> ratio {kg-H2O/kg-air}
>
> flow/zone, !- outside air method
>
> 0, !- outside air flow per person {m3/s}
>
> 1.167, !- outside air flow per zone {m3/s}
>
> 1, !- zone sizing factor
>
> flow/zone, !- cooling design air flow method
>
> 5.139, !- cooling design air flow rate {m3/s}
>
> flow/zone, !- heating design air flow method
>
> 5.139; !- heating design air flow rate {m3/s}
>
>
>
> As I?ve read in the mailing list and in the EnergyPlus documentation, the
> flow rates are sized on the sum of zone air flow rates. If I define
> flow/zone method, design calculated flow rates are override. For this
> reason, I didn?t change the flow rate fields in the System Sizing to let
> the program compute the flows I?ve entered in the zone sizing object.
>
>
>
> SYSTEM SIZING,
>
> UTA_BO 2, !- name of an AIR PRIMARY LOOP object
>
> sensible, !- type of load to size on
>
> autosize, !- Design (minimum) outside air volumetric
flow
> rate {m3/s}
>
> 1, !- minimum system air flow ratio
>
> 7, !- Preheat design set temperature {C}
>
> 16, !- Central cooling design supply air
> temperature {C}
>
> 25, !- Central heating design supply air
> temperature {C}
>
> noncoincident, !- Sizing Option
>
> no, !- Cooling 100% Outside Air
>
> no, !- Heating 100% Outside Air
>
> 0.008, !- Central cooling design supply air humidity
> ratio {kg-H2O/kg-air}
>
> 0.008, !- Central heating design supply air humidity
> ratio {kg-H2O/kg-air}
>
> design day, !- cooling design air flow method
>
> , !- cooling design air flow rate {m3/s}
>
> design day, !- heating design air flow method
>
> ; !- heating design air flow rate {m3/s}
>
>
>
> In the components (coils, fan?) I left the fields with the autosize
option.
>
>
>
> To simulate a worst case scenario, I defined the day type as
WinterDesignDay
> and defined the internal gains schedule to off for this day.
>
>
>
> I ran the sizing objects and the design day simulation and I? get the
> following warning:
>
>
>
>
>
> ** Warning ** The design coil load is zero for COIL:Water:SimpleHeating P1
-
> SALA_CIRURGIA REHEAT COIL
>
> ** ~~~ ** The autosize value for max water flow rate is zero
>
> ** ~~~ ** To change this, input a value for UA, change the heating
> design day, or lower
>
> ** ~~~ ** the system heating design supply air temperature
>
>
>
> To debug the problem I? ve asked the following report variables:
>
> Zone/Sys Sensible Load Predicted
>
> Zone/Sys Thermostat Heating Setpoint
>
>
>
> I don?t understand why I get this warning because zone temperature is
lower
> than the set-point, a heating load is predicted and the thermostat heating
> set point is 20ºC. I also checked the component connections, flow rates
and
> availability schedules and everything seems to be alright.
>
>
>
> I?m missing something? Could anyone help me?
>
>
>
> Thanks in advance for your help
>
>
>
> Best regards
>
>
>
>
>
> Filipe Madureira
>
> Tel: +351 919 293 876 | E-mail: filipe.madureira@xxxxxxxxxxxxx
>
> __________________________________________________________________
>
> FluidInova, Engenharia de Fluidos, SA
>
> TECMAIA - Parque de Ciência e Tecnologia da Maia
>
> Rua Engº Frederico Ulrich, nº 2650 | 4470-605 Moreira da Maia | Portugal
>
>
> Tel: (351) 229 408 265 | Fax: (351) 229 408 266
>
> E-mail: <mailto:geral@xxxxxxxxxxxxx> geral@xxxxxxxxxxxxx | Web:
> <http://www.fluidinova.pt/> http://www.fluidinova.pt/
>
>
>
>
>
> [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.pdf under the
Documentation link and press the "search" button.
>
> Yahoo! Groups Links
>
>
>
>
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.pdf under the
Documentation link and press the "search" button.
Yahoo! Groups Links
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.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/EnergyPlus_Support/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx
mailto:EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/