About the General Tab

Use the General tab of the Heating and Cooling Loads dialog to define parameters for a heating and cooling loads analysis.

• Click Analyze tabReports and Schedules tab Heating and Cooling Loads.

You can modify this information before a loads analysis or after to make it comply with your specifications.

• Building Type: Specifies the type of building according to the gbXML schema 0.37 (similar to ASHRAE).
• Location: Specifies the geographic location for the model. The location establishes the climate and temperatures used in loads calculation.
• Ground Plane: Specifies the level that serves as the ground level reference for the building. Surfaces below this level are considered to be underground. The default level is zero.
• Project Phase: Specifies the stage of construction to use for analysis.
• Sliver Space Tolerance. Specifies the tolerance for areas that will be considered sliver spaces.
• Building Envelope: Specifies the method to use to determine the building envelope.
  • Use Function Parameter. (default) This method uses the Function type parameter of walls, floors, and building pads to determine the building elements considered to be part of the building envelope. If a wall has one adjacent space, analytical surfaces originating from the wall are classified as exterior surfaces. If a wall has two adjacent spaces and its function is Exterior, Foundation, Retaining, or Soffit, analytical surfaces originating from the wall are classified as interior surfaces. If the wall's function is Interior or Core Shaft, analytical surfaces originating from the wall are classified as interior surfaces, regardless of the number of adjacent spaces.
  • Identify Exterior Elements. This method uses a combination of ray-casting and flood-fill algorithms to identify the building elements that are exposed to the outside of the building, the building envelope. Analytical surfaces originating from the building elements in the envelope are classified as exterior or shading surfaces.
• Analytical Grid Cell Size: Specifies the cell size for the uniform cubical grid. This is the base size of the 3D grid cells, or cubes, used to divide the building shell bounding box into a uniform cubical 3D grid. This parameter is available when Building Envelope is set to Identify Exterior Elements.
• Building Service: Specifies the heating and cooling system for the building.
• Schematic Types: Specifies the constructions type for the building. Click to open the Schematic Types dialog, where you can specify the materials and insulation (U-values) for the building.
• Building Infiltration Class: Specifies an estimate of outdoor air that enters the building through leaks in the building envelope.

  Infiltration can be specified as:

  • Loose - 0.076 cfm/sqft for tightly constructed walls.
  • Medium - 0.038 cfm/sqft for tightly constructed walls.
  • Tight - 0.019 cfm/sqft for tightly constructed walls
  • None - infiltration is excluded from the calculation of loads.
• Report Type: Specifies the level of information provided in the heating and cooling loads report. You can select Simple, Standard, or Detailed.
• Use Loads Credit: Allows for accounting of heating or cooling “credit” loads that take the form of negative loads. For example, heat that leaves a zone through a partition into another zone can be a negative load/credit.