Using this section requires choosing a workspace and installing the Sample Library. See Setting up Vulcan Software for instructions. Batch modelling, particularly with customised parameters or merges, can produce unexpected outputs, so users are responsible for checking the inputs and results.
Structure of the Scenarios Section
The Scenarios section of the Vulcan app enables use of the Home Energy Model outside of compliance wrappers (which can be used through the Calculate section), such as to:
Use alternative data for weather, occupancy and controls than what is automatically set by FHS or other wrappers. This can be useful to calibrate models to actual or potential dwelling use.
Understand detailed half-hourly outputs, including heat balance and heating/cooling system data.
Test the impact of design changes on outputs without creating new input files.
Defining Batch Configs and Scenarios
Batch simulation configurations (Batch Configs) are created and edited in the Scenarios section, and saved into the user's workspace under input/batch_configs.
All Batch Configs must have a Base input file created from the Geometry section, as well as a wrapper. Additional parameters can be chosen from the categories outlined below.
If multiple parameters are chosen for a single category within a single scenario, these are both modelled as separate permutations. This approach would be used, for example, if modelling a single dwelling with two separate weather files. Alternatively, separate scenarios can be used. The total number of permutations modelled is visible at the top of the page.
Batch Parameters
Batch Configs are built from parameter categories. The app groups these into Core Inputs, Fabric, and Systems & Controls.
Core Inputs
Base input file: The dwelling input created from the Geometry section. Each Batch Config needs at least one base input.
Model wrappers: Choose how the model should run. fhs_compliance creates detailed FHS outputs, fhs_assumptions applies FHS assumptions while preserving a core-style run, and passthrough runs the model without a compliance wrapper. If the base input was created for FHS validation, use an FHS wrapper rather than passthrough.
External conditions / weather files: Choose the weather or external conditions used for the simulation. An external conditions file provides the minimal information required by HEM to model local weather conditions. A weather (epw format) file can override the external conditions choice. Note that ECaaS will use a single compliance weather file.
Location: Sets location-related conditions for infiltration and ventilation, such as exposure, terrain, ventilation zone height, and altitude.
SAP XML: Toggles creation of a SAP10 XML file in the outputs.
Additional outputs: Toggles optional post-processing outputs, such as heat balance and detailed heating/cooling files.
Compliance settings: Varies inputs used for HEM:FHS runs, such as Part O/G settings, bedroom and wet room counts, ground floor area, and heating control type.
Fabric
Simplified fabric: Varies thermal properties for windows, walls, roofs, doors, party elements, ground floors, and thermal bridges.
Airtightness: Varies airtightness test pressure and test result.
Glazing: Varies the amount of glazing on external walls within selected orientations.
Orientation: Rotates building elements to test different dwelling orientations.
Systems & Controls
Heat source: Varies wet heat sources such as heat pumps, boilers, heat batteries, or immersion heaters.
Hot water source: Varies the hot water system, such as a combi boiler, cylinder, heat pump cylinder, or immersion heated cylinder.
Hot water demand: Varies hot water use assumptions.
Events: Sets hot water event patterns, such as repeated draw-offs over a day, week, or year.
Space heat emitters: Creates or replaces emitters for a space heating system, such as radiators or underfloor heating.
Space heat systems: Creates or replaces the wider space heating system linked to the heat source and emitters.
Space cooling systems: Creates or replaces space cooling systems.
Mechanical ventilation unit: Creates or replaces the mechanical ventilation unit.
Lighting: Creates or replaces lighting assumptions, including zone-specific lighting where relevant.
Solar systems: Creates or replaces solar PV assumptions.
Battery systems: Creates or replaces battery assumptions.
Controls: Varies control assumptions such as hot water and space heating controls.
Internal gains: Can be used for core-style scenarios. This category may be hidden when an FHS wrapper is selected, because those assumptions are set by the wrapper.
Tariffs are managed in the Results section for cost metrics, rather than selected as a Scenarios category.
Most parameters can be duplicated, but weather files and model wrappers are single-pick categories. Parameters that are not part of the initial sample library can also be edited. Schema validation is provided for editing the base JSON and some other parameters, but this should be treated as indicative for custom merge categories.
Running Batch Simulations
Batch Configs that are saved appear in the Simulations Panel.
Batch Configs can be selected with a click. When Run Simulation is clicked, Configs are queued for local simulation. Simulation progress is visible through a loading bar. Simulations that do not have any associated output files are shown as To do. Simulations currently running are shown as Running. Simulations that produce all expected output files are shown as Complete. Simulations that either have an error or only partially produce expected files are shown as Error.
Very large scenario grids are blocked above 500 permutations. If this happens, split the work into smaller Batch Configs or reduce the number of selected parameters.