Energy Calculations

Thermal and energy performance calculations for Buildings. Determines heat demand, transmission losses, U-values, and energy class for current state and renovation Scenarios.

Architecture

Layer	Location
Calculation parameters route	backend/src/routes/building-calculation-parameters.ts
U-value calculator	backend/src/lib/u-value-calculator.ts
Typology U-values route	backend/src/routes/typology-u-values.ts
Frontend cards	BuildingCalculationParametersCards
Frontend table	BuildingCalculationParametersTable
U-value hook	frontend/src/hooks/useUValueCalculation.ts
Data hook	frontend/src/hooks/useCalculationParametersData.ts
Constants	shared/constants.ts (thermal bridge methods)

Database

Table	Purpose
buildingCalculationParameters	Per-building calculation inputs and results

Calculation Types

Calculation	Description
U-value	Thermal transmittance of Building Components (walls, roof, windows, floor)
Heat demand	Annual heating energy requirement (kWh/m2a)
Transmission losses	Heat loss through building envelope
Energy class	German energy efficiency rating (A+ through H)

U-Value Calculator

backend/src/lib/u-value-calculator.ts computes U-values based on:

• Component layer composition (material, thickness, conductivity)
• Surface resistance values (interior/exterior)
• Thermal bridge correction factors

Typology Reference Data

backend/src/routes/typology-u-values.ts provides reference U-values based on building type and construction year. Seed data at backend/src/db/seeds/typology-u-values.ts (173KB) contains the reference database sourced from German building typology standards.

Thermal Bridge Methods

Defined in shared/constants.ts. Methods include:

• Detailed calculation (per-bridge analysis)
• Simplified (flat surcharge on U-values)
• Equivalent length method

Energy Class Flow

[[Building Components]] with layer data
  --> U-value calculation per component
  --> Transmission heat loss coefficient
  --> Heat demand calculation
  --> Energy class determination (A+ to H)
  --> Compare before/after [[Measures]] applied

Related

• Buildings — building entity with calculation parameters
• Building Components — component-level thermal data
• Measures — renovation measures that change U-values
• Scenarios — scenarios contain measure sets
• Scenario Planning — compare energy outcomes across scenarios
• Database Architecture — calculation parameter storage