Retrofit Frontier: every works bundle simulated before the first quote
An energy audit gives you one or two scenarios drawn from measurements taken by someone else. The Scenario Simulator gives you the whole frontier, computed on the geometry the Reconstruction Run just measured.
From As-Built Model to thermal model
The Scenario Simulator reads the As-Built Model and the Element Ledger: wall areas and thicknesses by orientation, glazing areas and frame types, slab and roof construction, the radiator and pipe inventory, and the openings that define thermal zones. It builds a multi-zone model directly from that geometry, 62 zones for the reference building, instead of from a hand-entered sketch, so envelope areas are the measured ones.
Calibration to metered consumption
Before any scenario runs, the model is calibrated against the building's metered consumption: at least one heating season, three when the owner has them. Infiltration, internal gains, and heating set-points are fitted until the monthly coefficient of variation of the root mean square error is inside the accepted band. The reference building reached 9.8%. A model that cannot be calibrated is reported as such, with the reason, instead of producing confident numbers.
Works bundles
A works bundle is one combination of measures: insulation thickness on each facade orientation, roof and floor insulation, window performance, ventilation type, heating and hot-water system, and the sequencing constraints your programme imposes. The combinations run into the tens of thousands. The Scenario Simulator simulates them in accelerator batches over an hourly year, at 6,500 to 18,000 bundles per GPU-hour, and prices each one from the Trade Lot Takeoff and your unit-rate library.
The frontier
The chart shows the bundles simulated for the reference building. Grey points are dominated: another bundle reaches a better class for less money. The red points are the Retrofit Frontier, the bundles worth discussing with the general assembly or the investment committee. Hover a point to see its measures, its cost, and its energy class.
Sample of the 12,400 bundles simulated for the reference building. The selected bundle is F-15: wall insulation 160 mm, roof insulation, windows to Uw 1.0, humidity-controlled ventilation, and a condensing boiler replacement, at 29,600 euros per dwelling and 147 kWh per m2 per year.
What the frontier is not
The Retrofit Frontier is a decision tool for the owner and the project manager. It does not replace the regulatory energy diagnosis, which is issued by a certified diagnostician, and it does not replace the design phase: the selected bundle becomes the basis of the tender, and the appointed design team details it. The simulated energy class is reported with its calibration error so nobody mistakes a model for a certificate.
Outputs
Each frontier bundle exports with its measure list, its priced schedule by trade lot, its simulated consumption by month, its energy class and carbon, and the calibration report. The selected bundle is written into the Scope Pack.
See the reference building