Questions from beginners

What is building performance simulation?

Using a computer model to predict how a building will perform before it is built: how much energy it uses, how hot or cool it gets, how bright it is, how air moves through it. The results let you compare design options with numbers.

What are the main types?

• Energy and thermal: energy use, cooling loads, indoor temperature for every hour of the year.
• Daylight: natural light and glare.
• CFD (computational fluid dynamics): airflow, ventilation, temperature within a space.
• Urban microclimate: temperature, wind and radiation around buildings and across a neighbourhood.

Which software should I start with?

Several free tools are enough to learn: EnergyPlus and OpenStudio for energy, Ladybug Tools if you use Rhino/Grasshopper, Climate Consultant to read climate data. The full list is on the Resources page.

Where do I get weather data for Vietnam?

EPW weather files for many Vietnamese stations are free on Climate.OneBuilding.Org. Climate data for design is set out in QCVN 02:2022/BXD. See Resources.

What is a "typical meteorological year" (TMY) file?

One year of weather assembled from the most typical months across many years of records. It represents average conditions, not the hottest year. To test extremes, use other data as well.

Are simulation results accurate?

Simulation is strong for comparing options. Absolute numbers depend on the inputs: weather, materials, schedules, the cooling system. State your assumptions and test how sensitive the result is to the important ones.

Does simulation matter for codes and green ratings?

Yes. The energy-efficiency regulation (QCVN 09:2017/BXD, and QCVN 04-3:2026/BXD from 1 February 2027) and ratings such as LOTUS, LEED and EDGE all deal with energy performance. How simulation can be used to show compliance is set out in each document's own text; read the original.

Who can I ask?

Send us your question by email. Good questions get answered at the next technical session.