Re: [EnergyPlus_Support] Why Inside and Outside face temperaures for a floor surface are same ?

According to the following definition of Adiabatic surfaces (given in the input/output reference of energy plus documentation (buildingsurface: detailed)), there can be heat flow through this surface but not out of the outside face of the surface. If the surface stores energy then it should have a temperature difference throughout the surface.

Adiabatic ? an internal surface in the same Zonne. This surface will not transfer heat out of the zone, but will still store heat in thermal mass. Only the inside face of the surface will exchange heat with the zone (i.e. two adiabatic surfaces are required to model internal partitions where both sides of the surface are exchanging heat with the zone). The Outside Boundary Condition Object can be left blank.

From: Edward G. Lyon <eglyon@xxxxxxx>
To: "EnergyPlus_Support@xxxxxxxxxxxxxxx" <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Friday, August 9, 2013 3:43 PM
Subject: RE: [EnergyPlus_Support] Why Inside and Outside face temperaures for a floor surface are same ?

The outside boundary is adiabatic, no heat flow, so both sides have to be the same temperature?

Ned Lyon, P.E. (MA, WV)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
www.sgh.com

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of qureshi.faran
Sent: Friday, August 09, 2013 9:35 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Why Inside and Outside face temperaures for a floor surface are same ?

I have a building model with its floor having one insulation layer. The details are given below. My question is that the energy plus simulation shows me exactly the same temperatures for the Inside and the Outside face of this floor. I am expecting a difference due to insulation layer. How can this be explained ?

BuildingSurface:Detailed,
Zn001:Flr001, !- Name
Floor, !- Surface Type
Slab Floor with Radiant, !- Construction Name
ZONE ONE, !- Zone Name
Adiabatic, !- Outside Boundary Condition
, !- Outside Boundary Condition Object
NoSun, !- Sun Exposure
NoWind, !- Wind Exposure
1.000000, !- View Factor to Ground
4, !- Number of Vertices
15.24000,0.000000,0.0, !- X,Y,Z ==> Vertex 1 {m}
0.000000,0.000000,0.0, !- X,Y,Z ==> Vertex 2 {m}
0.000000,15.24000,0.0, !- X,Y,Z ==> Vertex 3 {m}
15.24000,15.24000,0.0; !- X,Y,Z ==> Vertex 4 {m}

Material,
INS - EXPANDED EXT POLYSTYRENE R12 2 IN, !- Name
Rough, !- Roughness
5.0000001E-02, !- Thickness {m}
2.0000000E-02, !- Conductivity {W/m-K}
56.06000, !- Density {kg/m3}
1210.000, !- Specific Heat {J/kg-K}
0.9000000, !- Thermal Absorptance
0.5000000, !- Solar Absorptance
0.5000000; !- Visible Absorptance

Construction:InternalSource,
Slab Floor with Radiant, !- Name
4, !- Source Present After Layer Number
4, !- Temperature Calculation Requested After Layer Number
1, !- Dimensions for the CTF Calculation
0.1524, !- Tube Spacing {m}
CONCRETE - DRIED SAND AND GRAVEL 4 IN, !- Outside Layer
INS - EXPANDED EXT POLYSTYRENE R12 2 IN, !- Layer 2
GYP1, !- Layer 3
GYP2, !- Layer 4
FINISH FLOORING - TILE 1 / 16 IN; !- Layer 5