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

Re: [EnergyPlus_Support] Simple Steady State simulation

Hello,
You are seeing the effects of the thermal radiant exchange with a sky that is colder than the surfaces.  To see the effects that you want to see all you have to do is set the line   ".9,    !- Absorptance:Thermal"   to a very small value ie. 0.001 .  This will effectively make the surfaces made with this concrete material low-e surfaces. 

Add these report variables lines to your current input file and you will see how the roof exterior temp is ~15C.  This of course with the effects from the walls drops the interior temp the ~4C that you are experiencing.  Then change the line in the material as shown above and the temperatures will be what you were expecting.

Report Variable,*,Surface Inside Temperature,hourly;
Report Variable,*,Surface Outside Temperature,hourly;

You are attempting to run cases to give yourself confidence in the algorithms and it is always interesting to find that we forget things that the program remembers.

MATERIAL:REGULAR,
concreteWall, !- Name
MediumSmooth, !- Roughness
.3, !- Thickness {m}
1.7, !- Conductivity {W/m-K}
2240, !- Density {kg/m3}
836, !- Specific Heat {J/kg-K}
.9, !- Absorptance:Thermal
.7, !- Absorptance:Solar
.7; !- Absorptance:Visible

Richard L.

Thanks
Dr. Richard J. Liesen  Ph.D. M.E.
Associate Director, Building Systems Laboratory
Department of Mechanical and Industrial Engineering
University of Illinois at Urbana-Champaign


At 11:35 AM 6/4/2002, cdharrisie2002 wrote:
Hi,
I am currently evaluating EnergyPlus as we hope to use it for
simulating the energy performance of a proposed new hospital building
in Dublin, Ireland. I have currently modelled a very simple concrete
cube for 2 design days, which have constant outdoor temperature. The
simulated inside zone temperature for both days is also constant but
about 4.5 degrees higher than the outdoor temperature. I expected the
temperatures to be the same, as there is no heat input to the
building. Is there a reason for the higher inside temperature or have
i modelled the building incorrectly?

Thank you in advance for your help.

Best regards

Colin Harris
Trinity College Dublin.

THE IDF FILE BELOW :-

!-Generator IDFEditor 1.05

!-NOTE: All comments with '!-' are ignored by the IDFEditor and are
generated automatically.
!-      Use '!' comments if they need to be retained when using the
IDFEditor.


!-   ===========  ALL OBJECTS IN CLASS: VERSION ===========

VERSION,
    1.0.1;                   !- Version Identifier


!-   ===========  ALL OBJECTS IN CLASS: BUILDING ===========

BUILDING,
    hospital,                !- Building Name
    0,                       !- North Axis {deg}
    Country,                 !- Terrain
    .04,                     !- Loads Convergence Tolerance Value {W}
    .004,                    !- Temperature Convergence Tolerance
Value {C}
    MinimalShadowing;        !- Solar Distribution


!-   ===========  ALL OBJECTS IN CLASS: TIMESTEP IN HOUR ===========

TIMESTEP IN HOUR,
     4;                      !- Time Step in Hour


!-   ===========  ALL OBJECTS IN CLASS: INSIDE CONVECTION ALGORITHM
===========

INSIDE CONVECTION ALGORITHM,
    Detailed;                !- InsideConvectionValue


!-   ===========  ALL OBJECTS IN CLASS: OUTSIDE CONVECTION ALGORITHM
===========

OUTSIDE CONVECTION ALGORITHM,
    Detailed;                !- OutsideConvectionValue


!-   ===========  ALL OBJECTS IN CLASS: SKY RADIANCE DISTRIBUTION
===========

SKY RADIANCE DISTRIBUTION,
     1;                      !- SkyRadianceValue


!-   ===========  ALL OBJECTS IN CLASS: SOLUTION ALGORITHM ===========

SOLUTION ALGORITHM,
    CTF;                     !- SolutionAlgo


!-   ===========  ALL OBJECTS IN CLASS: SHADOWING CALCULATIONS
===========

SHADOWING CALCULATIONS,
     20;                     !- Period_for_calculations


!-   ===========  ALL OBJECTS IN CLASS: ZONE VOLUME CAPACITANCE
MULTIPLIER ===========

ZONE VOLUME CAPACITANCE MULTIPLIER,
     1;                      !- Capacitance Multiplier


!-   ===========  ALL OBJECTS IN CLASS: RUN CONTROL ===========

RUN CONTROL,
    No,                      !- Do the zone sizing calculation
    No,                      !- Do the system sizing calculation
    No,                      !- Do the plant sizing calculation
    Yes,                     !- Do the design day simulations
    No;                      !- Do the weather file simulation


!-   ===========  ALL OBJECTS IN CLASS: LOCATION ===========

Location,
    Dublin,                  !- LocationName
    53.43,                   !- Latitude {deg}
    -6.25,                   !- Longitude {deg}
    0,                       !- TimeZone {hr (decimal)}
    85;                      !- Elevation {m}


!-   ===========  ALL OBJECTS IN CLASS: DESIGNDAY ===========

DesignDay,
    SummerDayDUB-IRL,        !- DesignDayName
    24.2,                    !- Maximum Dry-Bulb Temperature {C}
    0,                       !- Daily Temperature Range {C}
    17.2,                    !- Wet-Bulb Temperature At MaxTemp {C}
    99433,                   !- Barometric Pressure {Pa}
    0,                       !- Wind Speed {m/s}
    221,                     !- Wind Direction {deg}
    0,                       !- Sky Clearness
    0,                       !- Rain Indicator
    0,                       !- Snow Indicator
    27,                      !- Day Of Month
    7,                       !- Month
    Friday,                  !- Day Type
    0;                       !- Daylight Saving Time Indicator

DesignDay,
    WinterDayDUB-IRL,        !- DesignDayName
    2,                       !- Maximum Dry-Bulb Temperature {C}
    0,                       !- Daily Temperature Range {C}
    0,                       !- Wet-Bulb Temperature At MaxTemp {C}
    99433,                   !- Barometric Pressure {Pa}
    0,                       !- Wind Speed {m/s}
    221,                     !- Wind Direction {deg}
    0,                       !- Sky Clearness
    0,                       !- Rain Indicator
    0,                       !- Snow Indicator
    20,                      !- Day Of Month
    1,                       !- Month
    Friday,                  !- Day Type
    0;                       !- Daylight Saving Time Indicator


!-   ===========  ALL OBJECTS IN CLASS: MATERIAL:REGULAR ===========

MATERIAL:REGULAR,
    concreteWall,            !- Name
    MediumSmooth,            !- Roughness
    .3,                      !- Thickness {m}
    1.7,                     !- Conductivity {W/m-K}
    2240,                    !- Density {kg/m3}
    836,                     !- Specific Heat {J/kg-K}
    .9,                      !- Absorptance:Thermal
    .7,                      !- Absorptance:Solar
    .7;                      !- Absorptance:Visible


!-   ===========  ALL OBJECTS IN CLASS: CONSTRUCTION ===========

CONSTRUCTION,
    wall,                    !- Name
    concreteWall;            !- Outside Layer


!-   ===========  ALL OBJECTS IN CLASS: ZONE ===========

ZONE,
    cube,                    !- Zone Name
    0,                       !- Relative North (to building) {deg}
    0,                       !- X Origin {m}
    0,                       !- Y Origin {m}
    0,                       !- Z Origin {m}
    1,                       !- Type
    1,                       !- Multiplier
    20,                      !- Ceiling Height {m}
    70000;                   !- Volume {m3}


!-   ===========  ALL OBJECTS IN CLASS: SURFACEGEOMETRY ===========

SurfaceGeometry,
    UpperLeftCorner,         !- SurfaceStartingPosition
    CounterClockWise,        !- VertexEntry
    relative;                !- SurfaceGeometryKey


!-   ===========  ALL OBJECTS IN CLASS: SURFACE:HEATTRANSFER
===========

Surface:HeatTransfer,
    southWall,               !- User Supplied Surface Name
    WALL,                    !- Surface Type
    wall,                    !- Construction Name of the Surface
    cube,                    !- InsideFaceEnvironment
    ExteriorEnvironment,     !- OutsideFaceEnvironment
    ,                        !- OutsideFaceEnvironment Object
    SunExposed,              !- Sun Exposure
    WindExposed,             !- Wind Exposure
    .5,                      !- View Factor to Ground
    4,                       !- Number of Surface Vertice Groups --
Number of (X,Y,Z) groups in this surface
    0,                       !- Vertex 1 X-coordinate {m}
    0,                       !- Vertex 1 Y-coordinate {m}
    20,                      !- Vertex 1 Z-coordinate {m}
    0,                       !- Vertex 2 X-coordinate {m}
    0,                       !- Vertex 2 Y-coordinate {m}
    0,                       !- Vertex 2 Z-coordinate {m}
    50,                      !- Vertex 3 X-coordinate {m}
    0,                       !- Vertex 3 Y-coordinate {m}
    0,                       !- Vertex 3 Z-coordinate {m}
    50,                      !- Vertex 4 X-coordinate {m}
    0,                       !- Vertex 4 Y-coordinate {m}
    20;                      !- Vertex 4 Z-coordinate {m}

Surface:HeatTransfer,
    eastWall,                !- User Supplied Surface Name
    WALL,                    !- Surface Type
    wall,                    !- Construction Name of the Surface
    cube,                    !- InsideFaceEnvironment
    ExteriorEnvironment,     !- OutsideFaceEnvironment
    ,                        !- OutsideFaceEnvironment Object
    SunExposed,              !- Sun Exposure
    WindExposed,             !- Wind Exposure
    .5,                      !- View Factor to Ground
    4,                       !- Number of Surface Vertice Groups --
Number of (X,Y,Z) groups in this surface
    50,                      !- Vertex 1 X-coordinate {m}
    0,                       !- Vertex 1 Y-coordinate {m}
    20,                      !- Vertex 1 Z-coordinate {m}
    50,                      !- Vertex 2 X-coordinate {m}
    0,                       !- Vertex 2 Y-coordinate {m}
    0,                       !- Vertex 2 Z-coordinate {m}
    50,                      !- Vertex 3 X-coordinate {m}
    70,                      !- Vertex 3 Y-coordinate {m}
    0,                       !- Vertex 3 Z-coordinate {m}
    50,                      !- Vertex 4 X-coordinate {m}
    70,                      !- Vertex 4 Y-coordinate {m}
    20;                      !- Vertex 4 Z-coordinate {m}

Surface:HeatTransfer,
    roof,                    !- User Supplied Surface Name
    ROOF,                    !- Surface Type
    wall,                    !- Construction Name of the Surface
    cube,                    !- InsideFaceEnvironment
    ExteriorEnvironment,     !- OutsideFaceEnvironment
    ,                        !- OutsideFaceEnvironment Object
    SunExposed,              !- Sun Exposure
    WindExposed,             !- Wind Exposure
    0,                       !- View Factor to Ground
    4,                       !- Number of Surface Vertice Groups --
Number of (X,Y,Z) groups in this surface
    0,                       !- Vertex 1 X-coordinate {m}
    0,                       !- Vertex 1 Y-coordinate {m}
    20,                      !- Vertex 1 Z-coordinate {m}
    50,                      !- Vertex 2 X-coordinate {m}
    0,                       !- Vertex 2 Y-coordinate {m}
    20,                      !- Vertex 2 Z-coordinate {m}
    50,                      !- Vertex 3 X-coordinate {m}
    70,                      !- Vertex 3 Y-coordinate {m}
    20,                      !- Vertex 3 Z-coordinate {m}
    0,                       !- Vertex 4 X-coordinate {m}
    70,                      !- Vertex 4 Y-coordinate {m}
    20;                      !- Vertex 4 Z-coordinate {m}

Surface:HeatTransfer,
    northWall,               !- User Supplied Surface Name
    WALL,                    !- Surface Type
    wall,                    !- Construction Name of the Surface
    cube,                    !- InsideFaceEnvironment
    ExteriorEnvironment,     !- OutsideFaceEnvironment
    ,                        !- OutsideFaceEnvironment Object
    SunExposed,              !- Sun Exposure
    WindExposed,             !- Wind Exposure
    .5,                      !- View Factor to Ground
    4,                       !- Number of Surface Vertice Groups --
Number of (X,Y,Z) groups in this surface
    50,                      !- Vertex 1 X-coordinate {m}
    70,                      !- Vertex 1 Y-coordinate {m}
    20,                      !- Vertex 1 Z-coordinate {m}
    50,                      !- Vertex 2 X-coordinate {m}
    70,                      !- Vertex 2 Y-coordinate {m}
    0,                       !- Vertex 2 Z-coordinate {m}
    0,                       !- Vertex 3 X-coordinate {m}
    70,                      !- Vertex 3 Y-coordinate {m}
    0,                       !- Vertex 3 Z-coordinate {m}
    0,                       !- Vertex 4 X-coordinate {m}
    70,                      !- Vertex 4 Y-coordinate {m}
    20;                      !- Vertex 4 Z-coordinate {m}

Surface:HeatTransfer,
    westWall,                !- User Supplied Surface Name
    WALL,                    !- Surface Type
    wall,                    !- Construction Name of the Surface
    cube,                    !- InsideFaceEnvironment
    ExteriorEnvironment,     !- OutsideFaceEnvironment
    ,                        !- OutsideFaceEnvironment Object
    SunExposed,              !- Sun Exposure
    WindExposed,             !- Wind Exposure
    .5,                      !- View Factor to Ground
    4,                       !- Number of Surface Vertice Groups --
Number of (X,Y,Z) groups in this surface
    0,                       !- Vertex 1 X-coordinate {m}
    70,                      !- Vertex 1 Y-coordinate {m}
    20,                      !- Vertex 1 Z-coordinate {m}
    0,                       !- Vertex 2 X-coordinate {m}
    70,                      !- Vertex 2 Y-coordinate {m}
    0,                       !- Vertex 2 Z-coordinate {m}
    0,                       !- Vertex 3 X-coordinate {m}
    0,                       !- Vertex 3 Y-coordinate {m}
    0,                       !- Vertex 3 Z-coordinate {m}
    0,                       !- Vertex 4 X-coordinate {m}
    0,                       !- Vertex 4 Y-coordinate {m}
    20;                      !- Vertex 4 Z-coordinate {m}

Surface:HeatTransfer,
    floor,                   !- User Supplied Surface Name
    FLOOR,                   !- Surface Type
    wall,                    !- Construction Name of the Surface
    cube,                    !- InsideFaceEnvironment
    ExteriorEnvironment,     !- OutsideFaceEnvironment
    ,                        !- OutsideFaceEnvironment Object
    NoSun,                   !- Sun Exposure
    NoWind,                  !- Wind Exposure
    1,                       !- View Factor to Ground
    4,                       !- Number of Surface Vertice Groups --
Number of (X,Y,Z) groups in this surface
    50,                      !- Vertex 1 X-coordinate {m}
    0,                       !- Vertex 1 Y-coordinate {m}
    0,                       !- Vertex 1 Z-coordinate {m}
    0,                       !- Vertex 2 X-coordinate {m}
    0,                       !- Vertex 2 Y-coordinate {m}
    0,                       !- Vertex 2 Z-coordinate {m}
    0,                       !- Vertex 3 X-coordinate {m}
    70,                      !- Vertex 3 Y-coordinate {m}
    0,                       !- Vertex 3 Z-coordinate {m}
    50,                      !- Vertex 4 X-coordinate {m}
    70,                      !- Vertex 4 Y-coordinate {m}
    0;                       !- Vertex 4 Z-coordinate {m}


!-   ===========  ALL OBJECTS IN CLASS: REPORT VARIABLE ===========

Report Variable,
    *,                       !- Key_Value
    Outdoor Dry Bulb,        !- Variable_Name
    hourly;                  !- Reporting_Frequency

Report Variable,
    *,                       !- Key_Value
    Zone/Sys Air Temp[C],    !- Variable_Name
    hourly;                  !- Reporting_Frequency


!-   ===========  ALL OBJECTS IN CLASS: REPORT ===========

Report,
    Surfaces,                !- Type_of_Report
    DXF;                     !- Name_of_Report

Report,
    Variable Dictionary;     !- Type_of_Report






Yahoo! Groups Sponsor
ADVERTISEMENT
f992a63.jpg
f992adb.jpg

To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/






Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

Yahoo! Groups Sponsor
ADVERTISEMENT

To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.