# 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?

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}

!-   ===========  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
===========

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

SOLUTION ALGORITHM,
CTF;                     !- SolutionAlgo

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

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