Energy Model Description

  • A building is viewed as an aggregation of spaces (rooms). Spaces may be conditioned (heated and/or cooled) or unconditioned.
    • In TREAT Single Family: The maximum number of spaces allowed is 4
    • In TREAT Multifamily: The maximum number of spaces allowed is 100
  • Each space must have at least one surface (wall, ceiling, or floor). Only exterior surfaces and surfaces between heated and unheated spaces may be entered. The total number of surfaces in a project must not exceed 500. Up to 300 of them may be exterior surfaces (including exterior doors). There may be up to 100 unique wall constructions.
  • Each space may contain unlimited number of appliances and lighting and a ventilation fan.
  • Each exterior surface may contain multiple doors and windows. The total number of window records in the building must not exceed 500. A single window record may be used to describe multiple windows on the same wall by entering window quantity.
    • This is especially useful when modeling multiple windows that share the same wall or point in the same direction
  • Each wall may have a single overhang, to model shading. The overhang runs the full length of the wall, is located at the top of the wall and is a horizontal surface parallel to the ground.
  • The model building must have a heating system that may consist of up to two subsystems: main (primary) and backup (secondary). Each subsystem can have its own distribution system.
    • Back up heating is activated when the main heating capacity is exceeded.
  • The heating system can be connected to multiple thermostats (the building can have multiple heating zones).
  • Each heating/cooling zone may include any number of spaces (rooms).
  • The building may have a cooling system. The cooling system may share its distribution with a heating subsystem.
    • Heating and cooling systems share thermostats.
  • Each conditioned space must belong to one heating/cooling zone (controlled by one thermostat).
  • The leakage area of a heated space is distributed among its surfaces in proportion to the surface area.
  • If, in addition, the user assigns leakage area to surfaces, then only the remaining (unassigned) leakage is distributed among surfaces in proportion to the surface area.
  • Each project may contain a model of a single Base Building and unlimited number of improvement packages for that Base Building.
  • Fuel bills may be entered for the whole building or individually metered spaces.
  • The Project may include any number of individually metered spaces.
  • There may be only one rate for each fuel.
  • Each individually metered space may contain any number of utility bills for each fuel.
  • Utility bills for the same fuel and the same individually metered space must not overlap.
  • Both estimated and actual bills may be entered.
  • Billing analysis is performed for each fuel using utility bills for all individually metered spaces for the specified analysis period.
  • The Building may have both main and back up heating fuels.
  • If there are two heating fuels then the billing analysis is performed using the aggregated heating usage of both fuels; it is not calculated for each fuel individually.