HVAC Systems (FP)

Provides the information concerning HVAC Systems required for a basic building model. This information includes:

• Representation of components and their relation to spatial structures (sites, buildings and spaces) without connection to systems
• Line based representations at early design stages that enable routing, terminal location and main plant location information to be exchanged;
• Full 3D shape representations at detailed design stages that enable coordination between different building services systems, between services and structure and between services and the building construction elements.
  Information items that may be required about HVAC systems include:
• System name
• Terminal type, size, location, orientation, airflow rate, discharge velocity, pressure drop; supply air temperature may also be included for supply air systems.
• Duct section size, shape, location, flow rate, air velocity, pressure drop
• Duct fitting type, size, location, pressure drop
• Equipment type, size, location, pressure drop
• Shape of elements
• Connections between elements in the ductwork system
• Material from which elements are constructed
• Classification of elements
  Constraints that have been applied during the design of the ducting systems to limit or control duct sizing or equipment selection may also be included as part of the exchange requirement. These should be identified as a requirement by the user. Particular constraints considered include:
• Limiting pressure drop in a ductwork section
• Limiting velocity in a ductwork section
• Limiting dimensions for a ductwork section (height, width, diameter)
• construction standard
• Duct sizing method

HVAC Systems

Concept	Description	Type	Man
Model the HVAC System	Based on the IfcSystem object
ID	Set the global unique identifier	GUID
Owner History	Apply the owner history	Owner History (FP)
Name	Specify the name of the HVAC System	Text
Descripton	Specify a description for the HVAC System	Text
HVAC System Flow Properties	Based on IfcFluidFlowProperties
ID	Set the global unique identifier	GUID
Owner History	Apply the owner history	Owner History (FP)
Name	Specify the name of the HVAC System Flow Properties	Text
Descripton	Specify a description for the HVAC System Flow Properties	Text
Source	The source of the fluid flow properties (e.g., are these design values, measured values, etc.).	Enumeration
Type of Fluid (material)	The properties of the fluid (IfcMaterial)	Text
Dry Bulb Temperature	The dry bulb temperature of the air (IfcThermodynamicTemperatureMeasure )	Real
Wet Bulb Temperature	The wet bulb temperature of the air (IfcThermodynamicTemperatureMeasure )	Real
Flow Condition	Defines the flow condition as a percentage of the cross-sectional area. (IfcPositiveRatioMeasure )	Ratio
Flow Rate	The flow rate of the fluid. Either a mass or volumetric flow rate shall be defined. (IfcDerivedMeasureValue )	Enumeration
Velocity	Defines the velocity of the air. (IfcLinearVelocityMeasure)	Real
Pressure	Defines the pressure of the air. (IfcPressureMeasure)	Real
HVAC System Elements	Defines the group of objects which form this HVAC System. Note that the elements are related to the HVAC System object using the IfcRelAssignsToGroup relationship
Ducts	Defines the individual duct segments which form the HVAC System.	Model Flow Segment (duct, rigid) (FP) or Model Flow Segment (duct, flexible) (FP)
Equipment	Defines the items of equipment which are attached to the HVAC System	Model Ventilation Equipment (FP)
Fittings	Defines the fittings which form the HVAC System.	Model Flow Fitting (FP)
Ports	Defines the distribution ports which connect the duct segments of the HVAC System.	Model Distribution Port (FP)
System Space Relationship	Describes a connection relationship between a system and a spatial structure element in which the system may have a connection with one or more different spatial structure elements. Spatial structure elements include sites, buildings, building storeys and individual spaces. A system may be related to as many spatial structure elements as required by specifying multiple system/spatial structure element relationships
System Elements	Defines relationship of individual HVAC System elements with the spatial project structure based on IfcRelContainedInSpatialStructure.	Relationship