What Is Building Performance Simulation?
Building performance simulation (BPS) uses digital models to predict how a building will perform before it's built — energy use, daylight, thermal comfort, airflow and more. It lets architects test design decisions virtually instead of guessing or waiting until after construction.
Building performance simulation is computer modeling that predicts a building's energy, thermal, lighting and airflow behavior, most commonly summarized by Energy Use Intensity (EUI) = Total Annual Energy Use ÷ Floor Area.
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Step-by-step worked examples
An office building uses 500,000 kWh per year and has a gross floor area of 5,000 m². Find its EUI.
EUI = E / A EUI = 500,000 / 5,000 EUI = 100 kWh/m²/yr
A school consumes 180,000 kWh/yr across 3,000 m². Find EUI and compare to a 120 kWh/m²/yr benchmark.
EUI = 180,000 / 3,000 = 60 kWh/m²/yr 60 < 120 benchmark → the school performs better than the benchmark
A simulation shows a redesigned facade would cut annual energy use from 400,000 kWh to 320,000 kWh in a 4,000 m² building. Find the new EUI and % savings.
Old EUI = 400,000/4,000 = 100 kWh/m²/yr New EUI = 320,000/4,000 = 80 kWh/m²/yr Savings = (100-80)/100 = 20% reduction
Flashcards
Quick quiz
Q1.What does building performance simulation primarily predict?
Q2.A building uses 300,000 kWh/yr over 3,000 m². What is its EUI?
Q3.What does a lower EUI generally indicate?
Q4.Which is NOT typically evaluated by building performance simulation?
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Common mistakes
EUI accounts for building size, so bigger buildings always have higher EUI. — Correct: EUI normalizes by floor area, so a large efficient building can have a lower EUI than a small inefficient one.
Simulation results are exact predictions of real energy bills. — Correct: Simulations are estimates based on assumptions (occupancy, weather, equipment) — actual use can differ (the 'performance gap').
BPS is only about energy. — Correct: BPS also covers daylighting, thermal comfort, airflow/ventilation, and acoustics.
Simulation should only be run after the design is finalized. — Correct: It's most valuable early, while design changes are still cheap and easy to make.
FAQ
What is building performance simulation?
It's computer modeling used to predict a building's energy use, thermal comfort, daylighting, and airflow before it is constructed.
What is the formula for Energy Use Intensity?
EUI = Total Annual Energy Consumption ÷ Gross Floor Area, expressed in kWh/m²/yr.
What are examples of building performance simulation?
Examples include energy modeling with EnergyPlus, daylight analysis with Ladybug, and CFD airflow studies for natural ventilation.
How do you calculate a building's EUI?
Divide the building's total annual energy consumption (kWh) by its gross floor area (m²) to get EUI in kWh/m²/yr.