SimScale is a cloud-based simulation tool that allows engineers, designers, and architects to achieve certain credits within the well-established international building codes such as LEED, BREEAM, and WELL. Explore how CFD tools and simulation software can enhance modelling and building design. SimScale can be used to evaluate indoor thermal comfort and air quality, and various external comfort conditions.

1. By Dr. Naghman Khan & Arnaud Girin
Using SimScale for
Demonstrating Compliance
With LEED, BREEAM & the
WELL Building Standard
AEC webinar

2. About SimScale
Who we are
Founded in 2012 in Munich (Germany), and
currently with an international team on two
continents, SimScale is the world’s first
production-ready SaaS application for
engineering simulation.
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3. About SimScale
What we do
We created the world’s first cloud-based
platform for CFD, FEA and thermal simulation.
● 150k users worldwide
● 300k simulation projects
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4. Today we will dive into how Computational
Fluid Dynamics (CFD) can be used to
demonstrate compliance with common
building rating systems such as BREEAM,
LEED, and WELL.
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Today’s application
CFD for Compliance

5. 1. What is CFD?
2. SimScale live demo
3. Building rating systems
4. CFD for compliance
5. Avoiding exhaust air recirculation -
Case study
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Today’s application
CFD for Compliance

6. What is Computational
Fluid Dynamics (CFD)?

7. What is
Computational Fluid
Dynamics
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● Engineering simulation used to model the
detailed behavior of fluids.
● In AEC, we can use CFD to model wind and
urban microclimate, natural
ventilation/HVAC, thermal comfort, and more.
● With SimScale, you can access CFD on a
web-browser.

8. What is
Wind Simulation
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● Simulate real wind conditions and its influence
on a building/site. Used for:
○ External building aerodynamics
○ Pedestrian Wind Comfort (PWC)
○ Wind loading
○ Wind pressure coefficients (Cp)

9. What is
CFD for Ventilation/HVAC
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● Simulating the indoor environment
● Understanding the flow of air in/around a
space
● Airflow diffuser types
● Model different types of equipment e.g.
underfloor heating, chilled beams

10. The Importance of
Ventilation
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● Is the ventilation adequate and is there
enough fresh air inside a space?
● Recirculating air and air mixing
● Fresh air ratio
● Impact of air filters and HVAC equipment
● Draughts and thermal comfort
● Source https://www.bbc.co.uk/news/explainers-53917432

11. What is
CFD for Thermal Comfort
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● Temperature distribution within a space
(Internal or external)
● Derive thermal comfort outputs e.g. PPD,
PMV, average temperatures
● Use it to analyse how comfortable occupants
are inside a space
● Air quality, CO2, mean age of air

12. Building rating systems
A quick look at environmental certification systems.

13. What is a
Building rating system
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● An environmental certification system for
applying best practice design, construction,
and an operational methodology to a building.
● Goes beyond national and local building
regulations and guidelines.
● Use a credit/points system by category
● BREEAM, LEED, WELL, GreenMark,
GreenStar, PEARL, QSAS, Estidama, and many
more.

14. They have in common
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● Independently reviewed and certified
● Professional skills e.g. LEED AP
● Cover many categories:
○ Energy (loads, demand, renewables)
○ Environmental quality (Ventilation, CO2)
○ Water use and efficiency
○ Site sustainability
○ Travel/locality
○ Health and wellbeing
○ Materials
What do
Source: Building Research Establishment (BRE)

15. How can you show
compliance with the
rating systems?
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● Design tools, skills, and knowledge
● Specialist software tools to demonstrate the
sizing/calculations:
○ Thermal modelling/dynamic simulation
software
○ Daylight/climate
○ Materials/LCA
○ CFD
USA Embassy in London achieved LEED Platinum
Source: https://kierantimberlake.com/updates/london-embassy-achieves-leed-platinum

16. What are
Limitations of standard
tools?
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● Thermal/dynamic simulation tools are used to
calculate loads, energy, bulk airflow across a
time period using environmental inputs
(climate, materials) and internal gains
(occupancy, equipment, profiles) as input.
● Zonal models giving space average results for
a unit of time over a year typically.

17. What is
Time Series vs. Spatial?
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● Do you want time-series or spatial analysis?
○ Temperature
○ Air flow rates
○ CO2
● Thermal modelling tools will give you
time-series average data per zone.
● CFD will give you detailed sub-zone results.
For example, temperature or CO2 distribution
in a room.

18. What types of credits can
benefit from CFD
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● Environmental quality
● Ventilation/natural ventilation
● Thermal comfort
● Site analysis
● Where using CFD to complement thermal
modelling will improve accuracy (Cp)

19. Let’s take a closer look
LEED v4.1 New
Construction Credits
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● Integrative Process (IP)
● Sustainable Sites (SS)
● Energy & Atmosphere (EA)
● Indoor Environmental Quality (EQ)

20. Integrated design
Early stage energy model at
concept/massing stage:
● Show early stage design was
incorporated
● What impact did it have on final
design
● Who was involved?
Integrative Process (IP)
LEED
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Early stage box model
Concept/massing stage model is
perfect for:
● Pedestrian wind comfort study
● Fast and accurate
● Simulate multiple
shapes/massings
● Import your CAD model

21. Site Assessment/Open
Space/heat island reduction
Develop a deep understanding of
your site’s challenges and
opportunities.
● Atmosphere and climate
● Are there any strong prevailing
winds on the site?
● Are these desired for cooling
and ventilation, or will they add
to building loads?
Sustainable Sites (SS)
LEED
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Wind Simulation
Wind simulation can inform:
● Pedestrian comfort and safety
● Vegetation & green roofs
● Layout of streetscape
● Impact of wind on energy,
comfort and ventilation
● Evaluate Cp values
● Microclimate assessment for
heat island reduction

22. Optimize Energy Performance
Optimize building massing and
envelope, reduce heating and
cooling demands.
● Traditional domain of thermal
modelling/dynamic simulation
tools.
● Where can CFD be used to
complement these tools?
Energy & Atmosphere (EA)
LEED
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Using CFD
CFD can improve the accuracy of
your thermal/energy model.
● Evaluate wind pressure
coefficient (Cp) values in CFD
and import them into your
thermal/energy model
● Significantly impacts on:
○ Ventilation
○ Heating/cooling
loads
○ infiltration

23. Minimum IAQ Performance,
Enhanced IAQ Strategies,
Thermal Comfort
Designing for natural ventilation,
air flow paths and thermal
comfort is a complex task.
● Only CFD can be used to
evaluate complex building
facade pressures and buoyancy
which impact all of the above.
Indoor Environmental Quality (EQ)
LEED
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Using CFD
The behavior of air in and around
a building is dynamic:
● How is air speed at the
occupant level modelled?
● Are you simulating natural
ventilation properly, which is
impacted by Cp values?
● Airflow through various
diffuser types?
● How does opening a window
change the air-flow path?

24. BREEAM / WELL
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● Important categories:
○ Energy - Reduction of Energy Use and
Carbon Emissions
○ Health & Wellbeing - Thermal Comfort
and Indoor Air Quality
○ Pollution - Local Air Quality

25. Avoiding exhaust air recirculation
How we set up these simulations in the SimScale Platform.
Case Study
The case of a multistorey building

26. 1. Import CAD model of a multistorey building
into SimScale to evaluate air mixing:
a. Window and balcony openings, exhaust
vents, supply intakes
2. Add climate/location
3. Add boundary conditions
4. Simulate:
a. Pedestrian Wind Comfort (PWC)
b. Airflow/thermal with OpenFOAM
Setup
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27. Results
1. Roof air exhausts are used to extract the stale
air from spaces.
2. A mechanical system is uses to extract the air
with varying flow rates.
3. The plume spread is influenced by the climatic
wind speed, direction,turbulence, and context.
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28. 1. We can take a closer look at the
upstream/downstream effects of a buildings’
aerodynamics under various wind conditions.
2. This is especially useful for site assessment.
3. The impact of trees and vegetation can also be
accounted for.
Results
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25 km/h
15 km/h

29. 1. Using a multi-direction transient wind analysis
we can see the conditions under which:
a. The exhaust re-enters the building
through windows/balconies
b. Enters the supply/windows of
neighbouring buildings
2. This methodology is equally applicable to
pollution and waste gases from generators,
flues, chimneys, and industrial applications.
Results
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30. 1. A multi-direction wind analysis is conducted to
analyse the building aerodynamics and also
the pedestrian wind comfort according to City
of London Microclimate guidelines.
2. The same results can be used to export wind
pressure coefficients (Cp) and import into
thermal modelling tools.
Results
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31. Summary
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● Especially during the conceptual phase, CFD is
a powerful tool to predict many aspects of
building performance, such as:
○ Environmental quality
○ Ventilation / natural ventilation
○ Thermal comfort etc.
● CFD will help obtaining valuable credit
incommon building rating systems such as
BREEAM, LEED, and WELL.