Now we start with a new group - Thermal Zone Description/Geometry. Without thermal zones and surfaces, the building can’t be simulated. This group of objects (Zone, Surface) describes the thermal zone characteristics as well as the details of each surface to be modeled. Included here are shading surfaces. (Refer to Getting Started to EnergyPlus for more information on thermal zoning)
Information from the EnergyPlus Input Output Reference:
Zone
This element sets up the parameters to simulate each thermal zone of the building.
Field: North Axis
The Zone North Axis is specified relative to the Building North Axis. This value is specified in degrees (clockwise is positive).
Field(s): Origin (X,Y,Z)
The X,Y,Z coordinates of a zone origin can be specified, for convenience in vertice entry. Depending on the values in “SurfaceGeometry”, these will be used to completely specify the building coordinates in “world coordinate” or not. Zone Origin coordinates are specified relative to the Building Origin (which always 0,0,0).
Field: Type
Zone type is currently unused.
Field: Multiplier
Zone Multiplier is designed as a “multiplier” for zone loads. It takes the calculated load for the inputted zone and multiplies it and sends the multiplied load to the attached system to meet the demand. The system will have to be specified to meet the entire multiplied zone load and will report the amount of the load it can meet in the Zone/Sys Sensible Heating or Cooling Energy/Rate report variable. The default is 1.
Field: Ceiling Height
Zone ceiling height is used in several areas within EnergyPlus. Energyplus automatically calculates the zone ceiling height (m) from the average height of the zone. If this field is 0.0 or negative, then the calculated zone ceiling height will be used in subsequent calculations. If this field is positive, then the calculated zone ceiling height will not be used -- the number entered here will be used as the zone ceiling height. If this number differs significantly from the calculated ceiling height, then a warning message will be issued. Note that the Zone Ceiling Height is the distance from the Floor to the Ceiling in the Zone, not an absolute height from the ground.
Field: Volume
Zone volume is used in several areas within EnergyPlus. EnergyPlus automatically calculates the zone volume (m3) from the zone geometry given by the surfaces that belong to the zone. If this field is 0.0 or negative, then the calculated zone volume will be used in subsequent calculations. If this field is positive, then the calculated zone volume will be replaced by the number entered here. If this number differs significantly from the calculated zone volume a warning message will be issued.
Field: Zone Inside Convection Algorithm
The Zone Inside Convection Algorithm field is optional. This field specifies the convection model to be used in the zone. See the Zone Inside Convection Algorithm object for descriptions of the available models. If omitted, the algorithm specified in the Inside Convection Algorithm object is the default.