CFD & Thermal Modelling

Question: What is CFD modelling?

Answer: Computational Fluid Dynamics (CFD) is an advanced simulation technique that models the movement of air, heat, smoke and pollutants within and around buildings. CFD divides the space into millions of small cells and solves the equations governing fluid flow to predict air velocity, temperature, pressure and contaminant concentration at every point.

In building design, CFD is used to assess ventilation effectiveness, thermal comfort, smoke movement, external wind conditions, data centre cooling, car park ventilation and the dispersion of pollutants.

Question: What is thermal modelling?

Answer: Thermal modelling, also known as dynamic thermal simulation, predicts the temperatures, energy use and comfort conditions within a building over time. It uses hourly weather data, building fabric properties, glazing, occupancy, internal gains and services to calculate heating and cooling loads, energy consumption and the risk of overheating.

Thermal modelling is required for Part L compliance of complex buildings, TM52 and TM59 overheating assessments, Part O compliance, energy strategy reports and BREEAM energy and thermal comfort credits.

Question: When is CFD modelling required?

Answer: CFD is typically used where simpler methods cannot adequately represent the airflow, including:

• Natural ventilation design for atria, halls and deep-plan buildings
• Smoke ventilation and fire engineering strategies for Building Regulations Part B
• Car park ventilation design using impulse or jet fans
• Thermal comfort in large or unusual spaces
• Data centre and server room cooling
• External wind microclimate and pedestrian comfort
• Pollutant dispersion around buildings and plant
• Displacement ventilation and chilled beam design

Question: What is the difference between CFD and dynamic thermal modelling?

Answer: Dynamic thermal modelling treats each room as a single well-mixed zone and simulates performance over a full year, making it ideal for energy and overheating assessment. CFD provides a detailed three-dimensional picture of conditions within a space at a specific moment, making it ideal for understanding airflow patterns, stratification and local comfort. The two are often used together, with thermal modelling providing boundary conditions for CFD analysis.

Question: What software is used?

Answer: Syntegra Group uses industry-standard software including IES Virtual Environment for dynamic thermal modelling and IES MicroFlo and other CFD packages for airflow analysis. For Part L compliance, only Government-approved dynamic simulation software is used, and CIBSE weather files, including future climate scenarios, are applied for overheating assessments.

Question: How does thermal modelling support planning applications?

Answer: Thermal modelling underpins Energy Strategy Reports, demonstrating the Be Lean, Be Clean, Be Green carbon reductions required by the London Plan and local policies, and provides the TM52 and TM59 overheating assessments that many authorities now require at planning stage. Early modelling allows glazing, shading and ventilation to be optimised before the planning drawings are fixed.

Question: Why choose Syntegra Group for CFD and thermal modelling?

Answer: Syntegra Group provides CFD and dynamic thermal modelling for residential, commercial, education, healthcare and industrial projects across the UK. Our modellers are building services engineers who understand how the results translate into practical design decisions on ventilation, glazing, shading, plant selection and controls.

We deliver clear, well-presented reports suitable for planning submissions, Building Regulations compliance, BREEAM evidence and design optimisation, and coordinate the modelling with our energy strategy, overheating, acoustic and M&E design services.