[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[EnergyPlus_Support] Re: Help with override error



Hi Richard,

I've set the coil and it was working until I upped the entering humidity. I now get:
   ** Warning ** SizeWaterCoil: Coil="DOAS COOLING COIL", Cooling Coil has leaving humidity ratio > entering humidity ratio.
   **   ~~~   ** ..will be sized for 50% of entering humidity ratio.

EVENTHOUGH entering air from outside has humidity of 0.01178 and the coil is set to 0.001.

SizingPeriod:DesignDay, Summer Design Day in BBI Terminal,  !- Design Day Name
   32.0,                                          !- Max Dry-Bulb {C}
   10.3,                                          !- Daily Temp Range {C}
   0.01178,!21.74,                                            !- Wet-Bulb at Max {C}  gH2O/gDryAir
   100761.7,                                      !- Barometric Pressure {N/M**2}
   0,                                             !- Wind Speed {m/s}
   0,                                             !- Wind Direction {Degrees N=0, S=180}
   0.98,                                          !- Clearness {0.0 to 1.1}
   0,                                             !- Rain {0-no,1-yes}
   0,                                             !- Snow on ground {0-no,1-yes}
   15,                                            !- Day of Month
   7,                                             !- Month
   SummerDesignDay,                               !- Day Type -- used for schedules
   1,                                             !- Daylight Savings Time Indicator
   HumidityRatio,!WetBulb,                                       !- Type of humidity temperature Indicator
   ,                                              !- Relative Humidity Day Schedule(not used)
   ,                                              !- Dry-Bulb Temperature Range Modifier Type (not used)
   ;                                              !- Dry-Bulb Temperature Range Modifier Schedule (not used)

Coil:Cooling:Water,
  DOAS Cooling Coil,                                        !- Name
  2,                                                       !- Availability Schedule Name
  autosize,                                                !- Design Water Flow Rate of Coil {m3/s}
  autosize,                                                !- Design Air Volume Flow Rate {m3/s}
  6,!autosize,                                                !- Design Inlet Water Temperature {C}
  32,!autosize,                                                !- Design Inlet Air Temperature {C}
  18,!autosize,                                                !- Design Outlet Air Temperature {C}
  autosize,                                                !- Design Inlet Air Humidity Ratio {kg-H2O/kg-air}
  !autosize,                                                !- Design Outlet Air Humidity Ratio {kg-H2O/kg-air}
  0.0010,                                                   !- Design Outlet Air Humidity Ratio   Entering is 0.01178 ,0.0050 does not work
  DOAS Cooling Coil ChW Inlet,                             !- Coil Water Inlet Node
  DOAS Cooling Coil ChW Outlet,                            !- Coil Water Outlet Node
  DOAS Mixed Air Outlet,                                   !- Air Inlet Node Name
  DOAS Cooling Coil Air Outlet,                            !- Air Outlet Node Name
  DetailedAnalysis,                                        !- Type of Analysis
  CrossFlow;                                               !- Heat Exchanger Configuration


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jean marais" <jeannieboef@...> wrote:
>
> I have the following error:
> 
>  ************* Beginning System Sizing Calculations
>    ************* Beginning Plant Sizing Calculations
>    ** Warning ** In calculating the design coil UA for Coil:Cooling:Water DOAS COOLING COIL
>    **   ~~~   ** the apparatus dew-point is below the coil design inlet water temperature;
>    **   ~~~   ** the coil bypass factor is unrealistically large;
>    **   ~~~   ** the coil outlet design conditions will be changed to correct the problem.
>    **   ~~~   ** The initial design conditions are: Tair,in = 24.4500
>    **   ~~~   **                                    Wair,in = 9.478796E-003
>    **   ~~~   **                                    Twater,in = 6.0000
>    **   ~~~   **                                    Tair,out = 18.0000
>    **   ~~~   **                                    Wair,out = 8.000000E-003
>    **   ~~~   ** The revised design conditions are: Tair,out = 14.5987
>    **   ~~~   **                                    Wair,out = 9.371939E-003
> 
> All my coil inputs possible are autosized. Zone and System humidity designs are 0.008 (default). My outlet Tair design is 18 deg (as seen in the error msg.)
> 
> 1) What is going on here exactly?
> 2) How can I enter other parameters so that the error does not occur and no reheat is nessesary.
>




------------------------------------

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

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 currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

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:
    EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    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/