CFD Modelling to validate occupants’ thermal comfort profiles and buildings’ energy saving initiatives
In general, cities are warmer than the rural areas. This “Urban Heat Island” effect (UHI) phenomenon occurs because cities have limited vegetation to provide adequate shade and cooling. Big cities also consume large amounts of energy in electricity and fuel dissipating heat into the surroundings.
In Singapore, the UHI “Urban Heat Island” effect averages between 4°C and 7°C at certain times of the day. This UHI warming effect lowers thermal comfort which discourages people from participating in outdoor activities such as cycling or running. The heavy reliance on air-conditioning to maintain thermal comfort also result to high consumption of electricity and fuels. With the appropriate ventilation design and setup, CFD modeling can be applied to validate the efficiency of the ventilation designs to achieve the desired thermal comfort.
Thermal comfort levels may be achieved using natural ventilation means driven by wind or mechanical means using HVAC systems.
Coupled with good engineering knowledge and judgement to set up the appropriate parameters such as building porosity and wind conditions, CFD techniques can be used to provide the most innovative and rational approach to derive a natural ventilation design to achieve thermal comfort.
Acceptance Criteria for Thermal Comfort
Green Mark for Non-Residential Buildings NRB: 2015
Thermal Comfort Level | Area-weighted ave. air velocity |
Moderate | 0.2 m/s |
Good | 0.4 m/s |
Very Good | 0.6 m/s |
The naturally ventilated driveways, loading & unloading bays of the industrial development were remotely positioned at more than 12m away from the façade openings.
With consideration to the prevailing wind conditions and the vehicular exhaust emission levels, CFD modelling was conducted to assess the adequacy of the natural opening to ventilate and maintain safe working conditions for occupants at these remote areas.
The CFD results had concluded that safe working conditions for occupants were maintained in terms of average carbon monoxide concentration over a 1-hour period.
Car parks are often the place where fire incidents take place. They can reach high temperatures due to being enclosed and the high temperatures of vehicles, which can lead to disastrous fires upon oil leakage. A ductless jet fan ventilation system serves as an effective smoke ventilation system, increasing airflow velocities to eliminate excessive heat and venting away harmful smoke and vehicular fumes.
Ductless jet fan ventilation systems are powerful and only need to be installed at certain points, leaving room for other installations and improving visibility across parking decks.
According to ANSI/ASHRAE Standard 62.1-2007, CO2 concentrations in acceptable outdoor air typically range from 300 to 500 ppm.
Site measurements for the CO2 concentration in a typical residential unit were in the range from 400 to 450 ppm when no occupants are in the room.
A 24-hour continuous CFD simulation was conducted for the typical residential unit to assess the effectiveness of the ventilation systems in terms of CO2 concentrations in ppm.
The residential unit for a family of 4 members consists of 2 bedrooms, a living room and 2 bathrooms.
(Back from school and work)
450 ppm CO2 concentration at peak value in the living, dining and common area when occupants are back in the unit after work or school.
The CFD results had concluded that the ACMV system is efficient to maintain an acceptable CO2 concentration in the residential unit.
The study of wind driven rain is an important design consideration in the built environment which requires good knowledge of wind speed, rain drop sizes and rainfall intensity. Wind driven rain or driving rain can significantly affect the durability of building. An example of Wind-Driven Rain (WDR) phenomenon is that parts of your apartment ruined by rain after a sudden downpour with your windows open.
Wind-Driven Rain (WDR) Analysis is the study of the horizontal rain phenomenon when driven by wind, resulting in rain falling into naturally ventilated spaces.
Many modern buildings are now designed with spaces for natural ventilation which whilst effectively covered are still subject to wind-driven rain. Such “Wind-Driven Rain spaces” are Aircon ledges, Balconies, Carparks, Corridors, Lobbies, Linkways, Plant Rooms, Staircases, Terraces and so on.
Wind-Driven Rain (WDR) Analysis is the study of the horizontal rain phenomenon when driven by wind, resulting in rain falling into naturally ventilated spaces.
Thermal comfort in buildings refers to the state in which occupants feel neither too hot nor too cold, contributing to well-being, productivity, and health. At SHEVS IFT, we use Computational Fluid Dynamics (CFD) to simulate real-world conditions and validate ventilation designs for optimal comfort. Learn more about our comprehensive fire and environmental design services on our homepage.
CFD modelling allows our engineers to visualise airflow, temperature distribution, and pollutant dispersion throughout a space. These simulations enable precise adjustments to ventilation strategies, supporting sustainable HVAC performance and enhanced thermal comfort in buildings—a critical consideration in Singapore’s tropical climate.
Yes. Our CFD modelling services assess and validate ventilation systems based on standards such as Green Mark NRB:2015. We help quantify performance for air velocity and CO₂ levels, ensuring your building meets regulatory criteria. Explore our insights on sustainability and design performance in our blog.
Our CFD solutions are tailored to various environments, including residential units, carparks, driveways, commercial spaces, and more. Whether it’s assessing carbon dioxide levels in a home or airflow in naturally ventilated driveways, we ensure optimal outcomes across diverse building types.
For a project-specific consultation, feel free to reach out to our experienced team. We’ll assess your needs and propose an effective CFD-based solution to enhance thermal comfort in buildings. Get in touch with us via our contact page.
CFD Modelling can be used to derive an effective natural ventilation design to achieve thermal comfort.
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