.Buildings.ThermalZones.EnergyPlus_9_6_0.UsersGuide.Conventions

Information

Conventions

The following conventions are made:

• If a zone is in the idf file but not modeled in Modelica, then
  • EnergyPlus will simulate the zone as free floating, and
  • EnergyPlus will simulate the outside air infiltration if specified in the idf file.
  This allows unconditioned zones such as a basement or an attic to simulate in EnergyPlus without having to use an instance of Buildings.ThermalZones.EnergyPlus_9_6_0.ThermalZone.
• If a zone is in the idf file and modeled in Modelica using Buildings.ThermalZones.EnergyPlus_9_6_0.ThermalZone, then EnergyPlus will remove all infiltration objects for this zone. This is done because Modelica computes the mass balance of the zone air, and infiltration depends on the static pressure of the HVAC system. Pressure-driven infiltration can be modeled using Buildings.Airflow.Multizone, or a fixed infiltration rate can be imposed as is shown in Buildings.ThermalZones.EnergyPlus_9_6_0.Examples.SingleFamilyHouse.AirHeating.
• All EnergyPlus HVAC objects that are present in the idf file are removed when coupled to Spawn.
• Output variables and EMS actuators need not be present in the idf file.
• For the EnergyPlus envelope, either the CTF transfer function or the finite difference method can be used.
• The coupling time step is determined by EnergyPlus based on the zone time step, as declared in the idf file.
• In EnergyPlus, a year of simulation always has 365 days, i.e., leap years are not considered. This is done because in the Modelica Buildings Library, weather files are assumed to have a periodicity of 365 days.