Why only 5 total surfaces for a room model in the Modelica building library? It should be 6.
Below is a piece of example code coming from the instruction documents of ThermalZones.Detailed.MixedAir in Modelica building library.
Buildings.ThermalZones.Detailed.MixedAir roo( redeclare package Medium = MediumA, AFlo=64, hRoo=2.7, nConExt=2, datConExt(layers={matLayRoo, matLayExt}, A={64, 63}, til={Buildings.Types.Tilt.Ceiling, Buildings.Types.Tilt.Wall}, azi={Buildings.Types.Azimuth.S, Buildings.Types.Azimuth.W}), nConExtWin=nConExtWin, datConExtWin(layers={matLayExt}, A={43}, glaSys={glaSys}, hWin={2}, wWin={2}, fFra={0.1}, til={Buildings.Types.Tilt.Wall}, azi={Buildings.Types.Azimuth.S}), nConPar=1, datConPar(layers={matLayPar}, each A=10, each til=Buildings.Types.Tilt.Wall), nConBou=1, datConBou(layers={matLayFlo}, each A=64, each til=Buildings.Types.Tilt.Floor), nSurBou=1, surBou(each A=63, each absIR=0.9, each absSol=0.9, each til=Buildings.Types.Tilt.Wall), linearizeRadiation = true , energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, lat=0.73268921998722) "Room model" annotation (Placement(transformation(extent={{46,20},{86,60}})));
In this example code, two Exterior construction(ConExt), one Exterior construction with window(ConExtWin), one interior construction(Conpar), one ConBou and one SurBou is defined. Based on my understanding, the ConBou and SurBou is used for one wall for two adjacent room, because two adjacent room share one wall. The ConPar stands for an interior wall or partitions in a room.
So the question is: 2 ConExt (two Exterior wall without window) + 1 ConExtWin (one Exterior wall with window) + 1 ConBou (one ConBou connected to the SurBou in adjacent room, meaning one wall shared by this room and the adjacent room) + 1 SurBou (One SurBou connected to the ConBou in adjacent room, also meaning one another wall shared by this room and the adjacent room)
So the total surfaces is 5, but for every room, there should be 6 surfaces, no matter connected to adjacent room or outside air or ground soil. I find this problem in all examples, the total surfaces are 5 for all the other examples. Unless considering the ConPar as the sixth surface, but for the ConPar, the explanation in the instruction documents is very clear: “Interior constructions such as partitions within a room. Both surfaces of this construction are inside the room model and participate in the infrared and solar radiation balance. Since the view factor between these surfaces is zero, there is no infrared radiation from one surface to the other of the same construction.”
In addition, even considering the ConPar as the sixth surface, the Are in above code is A=10, that does’t match any wall’s size of this room. In this code, we can see the length, width and high for this room is 643.
