OpenBuildings™ Station Designer Help

Simulation dialog - Calculate tab

Contains controls used to setup and start a simulation. The Calculate tab can define which zones of a building to conduct an energy simulation for, the type of simulation, which weather data to use, and the length of the simulation.



Note: The Calculate tab is a subset of the Energy Simulation.
Tip: Units Display – Units are displayed using the default system of units that was defined for the project, but can be changed to display using alternative units.
SettingDescription
Buildings The Buildings panel contains a list of all the project buildings, and is used to select individual buildings to include them in the simulation.
Zones The Zones panel contains a list of all the zones defined for the selected building or buildings, and is used to select individual zones to include them in the simulation.
  • Zones pop-up menu – Used to select or deselect zones. Right click anywhere in the Zones panel to activate the following menu:
    • Select all – Selects all the zones in the Zones panel.
    • Select none – Deselects any selected zones in the Zones panel.
Rooms The Rooms panel contains a list of all the rooms defined for the selected zone or zones, and is used to select individual rooms to include them in the simulation.
Name Used to enter a name for the simulation.
CAUTION: The simulation will not be able to be started unless it is named. The Start button is only activated when the simulation is named.
Description Used to enter a description for the simulation.
Simulation Method Used to select the simulation method for which to generate a report.
Note: Equipment Sizing and Plant Energy types are available when a valid HVAC system is selected, rather than None.
These reports support the graph view displaying simulation parameter values stacked on top of each other including the plant energy and CO2 report.
HVAC Used to select an HVAC system to simulate from the HVAC systems defined in the project building. The HVAC and equipment section of the input data dictionary (idd file) and input data file (idf file) are more complex than the description of building geometry, internal gains, etc. because of the interconnections of the various parts of an HVAC system. There are several portions to the HVAC simulation. All of these parts must be correctly specified in order to arrive at a valid simulation model.
Note: Enabling the Include HVAC option automatically disables the Simple room model option.
Calculation Standard Used to select the ASHRAE 90.1 standard edition applicable for the simulation.
  • ASHRAE 90.1 2010 — When selected, baseline buildings and a budget building are included in accordance with all requirements defined in the ASHRAE 90.1 2010 standard.
  • ASHRAE 90.1 2007 — When selected, baseline buildings and a budget building are included in accordance with all requirements defined in the ASHRAE 90.1 2007 standard.
  • ASHRAE 90.1 2004 — When selected, baseline buildings and a budget building are included in accordance with all requirements defined in the ASHRAE 90.1 2004 standard.
Simple room model When on, only the building geometry and simple gains and losses are considered in the simulation.
Note: Enabling the Simple room model option automatically disables the HVAC drop-down list.
Create Baseline Buildings Used to select a baseline buildings option for the simulation. When enabled, Baseline Buildings are considered in the simulation. A simulation will be carried out for each of the four baseline building orientations (0°, 90°, 180° and 270°) in addition to the main project building simulation. An instance of the Simulation results dialog will open for each simulation.

For projects with 4 baseline buildings:

  • Use possibly modified baseline buildings dialog - If Baseline Buildings have already been modeled, and appear in the Energy Simulator Project Tree, you are prompted to continue with simulation regardless of whether or not the existing baseline buildings have been modified.
    • Yes - Click to use the baseline buildings that may have possibly been modified.
    • No - Click to not use the baseline buildings that may have possibly been modified. The baseline buildings will be generated automatically as part of the simulation.
  • ASHRAE Baseline Building Selection Dialog — Appears if Baseline Buildings have already been modeled, appear in the project tree, and you clicked Yes in the Use possibly modified baseline buildings dialog. The ASHRAE Baseline Building Selection Dialog is used to select the baseline buildings you want to include in the simulation.


    • Use user modifiable baseline building for [0° | 90° | 180° | 270°]
      • When on, the possibly modified baseline building for [Angle] selected from those available on the drop-down list is used in the simulation.
      • When off, the OpenBuildings Energy Simulator simulation generates the baseline building for respective [Angle] internally.
    • OK – Accepts and applies all changes made in the ASHRAE Baseline Building Selection dialog.

    For new projects with 1 baseline building:

    The Simulation selects only template building, instead of building for each rotation. The resultant reports will have four reports (See Results tab) created for above four rotations taking one template building instead of four baseline building.


    One template building was created instead four baseline buildings.

    The HVAC systems defined in the baseline buildings are used for the Calculation of the Proposed/Baseline Building Performance that complies with the ASHRAE 90.1 standard’s Appendix G.3.1 requirements. OpenBuildings Energy Simulator provides pre-defined HVAC systems that can be used for this purpose.

Show results on completion When on (default), simulation results are displayed immediately after the simulation is completed.
Create budget building Used to select a Budget building option for the simulation. When enabled, a Budget building is considered in the simulation. The budget building is a computer representation of a hypothetical design based on the actual proposed building design. This representation is used as the basis for calculating the Energy Cost Budget. Energy Cost Budget (ECB) is used as the basis for one of the ASHRAE 90.1 standard’s Mandatory Provisions compliance options; the Energy Cost Budget Method. The ECB Method is detailed in section 11 of the standard, and is referred to by the Mandatory Provisions detailed in section 6 of the standard. OpenBuildings Energy Simulator provides pre-defined HVAC systems that can be used for this purpose.
Weather data Used to select the Weather data profile from those available on the drop-down list to use for the simulation. the weather data populates the design day dates for cooling and heating and the design temperatures. The available weather profiles are defined in the Weather Manager.
  • Heating design day: — Displays the heating design day or the coldest day of the year. The heating design day date is a read only piece of data, and is determined by the weather data profile.
    • Design temperature – Displays the design temperature for heating.
  • Cooling design day: — Displays the cooling design day or the hottest day of the year. The cooling design day date is a read only piece of data, and is determined by the weather data profile.
    • Peak temperature – Displays the peak temperature for cooling.
Run Period Contains controls used to define the duration of the simulation. A simulation can last one day or a full year.
  • Start Day — Used to define the simulation run period start date. You can enter the date directly using the suggested format or click the down arrow to open the pop up calendar.
  • End Day — Used to define the simulation run period end date. You can enter the date directly using the suggested format or click the down arrow to open the pop up calendar.
  • Override 1st Day — Used to set overriding first day by specifying a of day selected from the pull-down list of week days.
  • Full Year — Used to set the simulation run period to be an entire year. Clicking the Full Year button automatically sets both the start date (01 Jan) and the end date (31 Dec).
Start Enabled when the simulation is given a name. Clicking the Start button starts the simulation, closes the Simulation dialog, and opens the Simulation results dialog.
Parent topic: Energy Simulation