Whether you're an architect, HVAC engineer, building designer, air conditioning technician or construction consultant, it's highly likely that you've heard of building simulation before. But what exactly is it? How can it help you save money and remain compliant? How much does it cost? What are the tangible benefits for your industry? In this handy guide, we've created an introduction to using simulation in the built environment, highlighting its many advantages for addressing HVAC challenges.

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What Is CFD?

Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses mathematics, physics and computational software to visualise, analyse, predict and solve problems involving fluid flows. CFD analysis involves the examination and analysis of such fluid flows, in accordance with physical properties including velocity, pressure, temperature and density.  Put simply, CFD simulation helps those in the built environment to test, analyze, predict and optimize their designs to increase system performance, reduce costs, become more energy efficient, and even increase profits.

New to CFD? CLICK HERE for an in-depth introduction to computational fluid dynamics.

Industry Trends: HVAC Market Growth

According to the new market research report "HVAC System Market - Global Forecast to 2023", the HVAC system market was valued at USD 181.00 Billion in 2018 and is expected to reach USD 251.60 Billion by 2023, at a CAGR of 6.80% between 2018 and 2023. Factors that are driving the growth of the market include increasing demand for HVAC systems for reducing energy consumption, extreme weather conditions, government tax credit and rebate programs, and growing demand for HVAC systems to upgrade old systems.

Untitled-13Expert Consulting highlight the key future market drivers in the HVAC market

Market for controllers and controlled equipment is expected to grow at the highest CAGR between 2018 and 2023

The research report analyzes the HVAC controls market on the basis of system, component, implementation type, application, and geography. Based on system, the HVAC controls market has been classified into temperature, ventilation, humidity, and integrated control system. The market has been segmented on the basis of component into sensors and controllers & controlled devices.

New construction to hold the largest size of the HVAC system market during the forecast period

The increase in urbanization has led to the demand for smart buildings. These buildings require efficient HVAC equipment, leading to the growth of the HVAC system market. Smart buildings are not only green/sustainable but are also intelligent; these buildings are equipped with advanced technologies, which include HVAC systems. HVAC systems provide a comfortable standard living environment. Governments are relying on smart buildings, which ensure a lower carbon footprint, 40% reduction in the usage of water, and less electricity consumption. Thus, developers and owners of buildings are trying to meet energy-efficiency guidelines related to HVAC systems - it is here, where CFD simulation tools will prove most advantageous. 

HVAC system market in APAC to grow at the highest CAGR between 2018 and 2023

Major APAC countries such as China, Japan, and India are the major consumers of HVAC systems. The governments of these countries have taken various measures to ensure that energy-efficient HVAC systems are being installed in new buildings. The collaboration of HVAC companies with major regulatory bodies is required to create awareness regarding HVAC implementation. Awareness among real-estate developers, architects, and engineers would ensure effective installation of HVAC in buildings, right from the designing stage. This would support the market for HVAC equipment. Increased awareness among consumers regarding the adoption of the star-labelled HVAC products, high use of VRV, and invertor-based AC systems have boosted the growth of the HVAC equipment market

Industry Trends: Advancing Net Zero Buildings

The World Green Building Council has led the way in the implementation of the Advancing Net Zero project (project steering committee), reflecting its goal of supporting market transformation towards 100% net zero carbon buildings by 2050. The infographic below shows the project framework including key target dates, definition for net zero carbon buildings, the action pathways being taken, and the key principles guiding their actions.

WorldGBC Advancing Net Zero Infographic v1_March 2018_low res2_0

Despite striving for 100% net zero buildings, WorldGBC does recognize that in most cases, 100% net zero buildings may not be entirely feasible. Therefore, buildings that are energy efficient and supply energy needs from renewable sources remains the most realistic target for the mass scale, in order to achieve the levels of global emission reductions set out in the Paris Agreement

The built environment must now bring together all professional departments and engage modern technology to meet these targets - here's a view from the industry. CFD simulation has the potential to play a significant role in improving the energy efficiency of buildings through effective analysis and optimization of HVAC environments. Learn more about how early CFD use can impact energy efficiency 

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CFD: The Future Of Building Simulation

The past ten years have seen many advances in the world of building simulation, but perhaps the forthcoming decade looks set to witness the biggest number of developments. Unlike the automotive and mobile communication sectors, the built environment has been slow to adopt technology in its practices. However, this looks set to change with the following influences likely to increase the adoption and use of building simulation in the next ten years:

  • The Cloud: Making high performance computing tools more accessible and affordable.
  • Climate Change: A higher focus on climate change and sustainability means developers will continue to develop new technology to increase energy efficiency. 
  • Building Certification: More developers will strive to achieve green building certification to showcase their environmental commitments.
  • Building Compliance: At a time when structural building safety is under the spotlight, developers face a need to comply with increasing government legislation to ensure occupant safety in the event of natural disasters or fire.
  • Building Information Modelling: BIM is now widely used in the built environment and simulation plays a key role in understanding the structure and function of a particular building in more detail.

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One of the most notable advantages of using CFD in HVAC situations, is the ability to simulate fluid flows and analyze HVAC performance without actually installing the HVAC system or even building a prototype. This allows for significant problems - and ultimately solutions, to be identified and devised to enhance a building's overall HVAC performance. Additionally, CFD simulation can be used to simulate existing systems to identify areas where performance can be improved.


Using simulation tools could enable architects, HVAC designers, engineers and building consultants to reduce overall project times through a more efficient design process. Design iterations can be reduced, deadlines met, and a greater level of confidence can be drawn from final designs. 


The use of CFD for HVAC purposes has been shown to have a tangible effect on both capital and operational cost reduction. Modern simulation tools enable users to cut capital costs as software is accessed and paid for on the fly (rather than having to invest in expensive hardware or licences). Simulation also means users can make more informed decisions before making large capital investments. Additionally, more energy efficient systems enable cuts to be made in operating costs.


The quality and quantity of a product, its development, and the potential for disease is closely related to the local temperature and humidity within a greenhouse or grow facility. These buildings are often difficult to control due to their large expanse, the position of doors or windows, and the placement of HVAC systems. CFD simulation helps to create a uniform climate which leads to simultaneous growing and development of plants, a reduced need for pesticides, and consistent product quality - allowing for better organization of the harvest and a higher customer satisfaction rate. 

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Using simulation tools effectively could even reduce the chances of a lawsuit through better health & safety compliance. When it comes to fire risk management, builders and architects must follow three basic principles: to prevent risk of fire, evacuate occupants safely and effectively, and to minimize damage to the building and surrounding area. CFD simulation tools can play a key role in predicting and simulating the behavior of fire and smoke, assisting with the effective implementation of fire safety procedures. CFD simulation can also play a role in helping satisfy building regulations and compliance around HVAC. In many countries, building regulations come into force if you seek to:

  • Put up a new building
  • Extend or alter an existing one
  • Provide services and/or fittings in a building such as washing and sanitary facilities, hot water cylinders, foul water and rainwater drainage, replacement windows, and fuel burning appliances of any type.

CFD simulations can help  to analyze a proposed design to better satisfy legislation and instil a greater level of confidence in user safety. 


The increased awareness of climate change has fuelled the use of simulation in the built environment. Developers are no longer simply 'complying' with building regulations at minimal expense, but are going further to achieve green certification and showcase their ethical credentials. CFD tools like EXN/Aero enable users to design more effective HVAC systems that work as intended, reduce wastage and bring down energy consumption, therefore reducing overall carbon footprint. 


LEED Certification

LEED, or Leadership in Energy and Environmental Design, is the most widely used green building rating system in the world. Available for virtually all building, community and home project types, LEED provides a framework to create healthy, highly efficient and cost-saving green buildings. LEED certification is a globally recognized symbol of sustainability achievement. CFD simulations can be effectively used to increase and improve the energy efficiency of a facility, therefore helping developers meet LEED credit requirements in a timely, cost-effective manner.




BREEAM is an international scheme that provides independent third party certification of the assessment of sustainability performance of individual buildings, communities and infrastructure projects. The BREEAM ratings range from Acceptable (In-Use scheme only) to Pass, Good, Very Good, Excellent to Outstanding and it is reflected in a series of stars on the BREEAM certificate. Assessment and certification can take place at a number of stages in the built environment life cycle, from design and construction through to operation and refurbishment. At the heart of the certification process are certification bodies – organisations with government approval (through national accreditation bodies) to certificate products, systems and services. Preparation for BREEAM certification using CFD simulation can ensure a greater level of success during the certification assessment stage, and provide greater confidence of compliance.

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ASHRAE Certification

With more than 56,000 members from over 132 nations, ASHRAE is a diverse organization representing building system design and industrial processes professionals around the world. More than 2,500 certifications have been earned by professionals who have demonstrated their knowledge and expertise in the HVAC&R industry. Those holding these certificates can benefit from the use of CFD simulation tools as they are recruited to projects around the world, with the goal of improving energy efficiency. Often faced with challenging HVAC environments, these certified consultants will now have access to high performance simulation tools to assist with meeting legal building requirements.

Click here for a list of all applicable local, state and national RFP and legal requirements in building energy auditing, energy modelling, commissioning process management, healthcare facility design, high-performance building design or operations & performance management.

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In many industries, the use of real-world tests is impractical, expensive, sometimes unsafe, and time-consuming.  For those looking to investors or to cut costs, anything that reduces project risk, and increases accuracy and profitability, has to be looked upon favorably. The information provided by CFD simulations makes it an effective way of reducing real world experiments, effectively providing a useful preliminary step before a final design or prototype is produced. Testing scope flexibility, timeliness, and visualization give product developers a much higher caliber understanding of how their HVAC system will perform. 



Thanks to the cloud, Envenio has made it possible to transform a regular laptop or desktop computer into a supercomputer, performing simulations faster and at a fraction of the cost than was previously available. This, combined with an on-demand, pay-as-you-go model, means smaller businesses can incorporate CFD simulation tools into client pitches or investment proposals, potentially becoming more attractive to clients and able to compete with larger counterparts.






Commercial & Residential Buildings

Optimal natural ventilation and HVAC systems are essential for maintaining a healthy and comfortable environment for occupants in offices, apartment blocks or hotels. However, the effective design, construction and operation of HVAC systems in a building require a good understanding of complex airflow patterns.

CFD simulation tools like EXN/Aero can play a key role in building design as well as the testing and optimization of heating and air conditioning systems. This enables designers, employers, landlords and business owners to satisfy thermal regulation compliance. Click here to find out more about designing better air conditioning systems with simulation.


Fire & Smoke Systems

Put simply, fire modelling can be used to demonstrate that the proposed building design (or retrofit of an existing building) achieves a commensurate level of safety in accordance with the building regulations of that particular country.

CFD tools like EXN/Aero help fire safety engineers to predict fire and smoke behavior in a particular building and assess the thermal response and analyze structural behaviors. This is useful not only due to the near impossibility of conducting realistic experiments on complete fire safety systems in a building, but also to provide a greater level of confidence in evacuation and smoke management systems.



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Indoor Farming Facilities

Many farmers use guesswork to run their fans and HVAC systems in farm buildings, wasting energy and money in an effort to create the optimal environment for crops or livestock.  CFD is also proving useful in increasing medicinal cannabis yields.

Using simulation, farmers could:

  • Better understand their buildings & make informed decisions.
  • Maximize performance of fans and ventilation systems by placing them where needed.
  • Prolong equipment life and prevent premature failure.
  • Increase efficiency and potentially reduce costs.
  • Reduce contamination & over-use of pesticides.

Computer Clusters & Data Centers

Reduced space and increased heat output of server units poses a significant challenge for the cooling system design of data centers. State-of-the-art cooling systems now use different types of systems (air or liquid cooled) and designs such as  'raised floor' or 'hot/cold aisles'.  One of the major concerns when designing an efficient air conditioning system is to eliminate possible “hot-spots” in the room. CFD tools like EXN/Aero can play an integral role in determining these hotspots as well as providing a detailed analysis of the heat dissipation rate and flow patterns in the room. Insight can also be provided into vent placement (both inlet and outlet), flow rate and temperature required of the cooling fluid and other design constraints for these systems.



Cleanrooms & Operating Rooms

Between 5 and 10 per cent of patients admitted to acute care hospitals acquire one or more infections, and the risks have been on an increasing trend during the past three decades. Controlling contamination in the hospital operating room environment is vital for the safety of patients and hospital personnel, and cleanrooms represent a specialist area of HVAC design where the goal is often to quickly remove as much contamination as possible.

Using CFD, engineers can quickly achieve this along with a number of other design objectives thanks to the ability to visualize airflow patterns and particle migration paths for a proposed or existing design.  Read more about using CFD simulation in challenging environments such as the operating room.

Enclosed Structures

Aircraft and vehicular hangars, tunnels and car parks by their very nature,  often pose a unique challenge for fire safety engineers. Large, open floored areas with high roof decks house expensive contents in addition to highly flammable fuel and a host of ignition sources.

CFD modelling is proving highly effective in this area to solve fundamental equations about fluid flow and heat transfer, both commonly associated with fire. The result is that predictions can be made as to how smoke and heat will move throughout the hangar, potentially with life-saving consequences, enabling the most effective fire-safety procedures to be implemented, and risk assessment to be more accurate.


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General HVAC System Optimization

CFD enables fluid flows to be simulated and performance to be analyzed in a range of HVAC systems wherever they may occur.  From refrigeration units through to vehicle air containing systems, computational fluid dynamics enables crucial problems to be identified and solutions to be devised, all with the goal of effectively enhancing HVAC performance within a particular environment. After simulation, design modifications can be suggested,  modifications can further be simulated and any kind of malfunctioning of HVAC systems can be mitigated for improved performance and better HVAC. Essentially, CFD can play a key role in improving building sustainability.



Arenas and Theatres

CFD simulation has proved to be an effective tool in providing foreseeable data for a number of different indoor environments. Arenas and theatres are often multipurpose buildings, hosting and facilitating everything from music concerts to ice hockey matches. For this reason, a thorough knowledge of the flow physics, along with an understanding of the building's natural ventilation and installed HVAC systems is essential. CFD simulation can provide improved knowledge of a multipurpose indoor environment, so as to inform adjustments to designs and a potential reduction in cost and energy outputs.




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CFD simulation has historically been reserved for huge enterprises with comparative budgets, able to justify multi-processor machines with eye-watering price tags. These days, the emergence of the cloud has enabled vendors like us to make simulation software more accessible AND affordable to those in the HVAC sector. Our straightforward pricing page highlights our pay-monthly approach, making it ideal for those with intermittent simulation needs who cannot justify expensive capital expenditure.

For the first time, CFD costs can be seen as an operating cost rather than capital expenditure, allowing HVAC engineers and consultants to only pay for what they need. Alternatively, you may choose to outsource your simulation project to experienced engineers like us, taking advantage of our convenient engineering services like the Discovery Project.

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With so much iterating involved in the built sector, and building designs changing on a daily or even hourly basis, multiple-day simulations are of no use so our EXN/Aero platform uses GPUs to finish simulations in hours instead of days. Faster simulation turnaround times mean you can react to ever-changing requests and iterate quicker on designs.


Contractors are often operating under heavy workloads and as such are sometimes too busy to run the simulations themselves. We at Envenio offer a range of engineering services to support you and your team. With the Discovery Project, our engineers will run your CFD project for you, returning the simulations and engineering data to you at the end of the process. This is a great way to expand your service offering to clients and access high performance software and experienced engineers to benefit your project objectives. 


In many cases, BIM users are artists and designers, while CFD has been reserved or outsourced to engineers. The perception that CFD can only be performed and understood by engineers has largely contributed to this, and a more integrated relationship between all parties would lead to higher quality conversations and informed decision-making. Tools like EXN/Aero are making simulation more accessible and able to be placed in the hands of architects, design consultants and HVAC engineers, who have the best understanding of a particular project's aims.


CFD terminology has often created a barrier around its use. Unlike previous CFD codes that required users to have a complex, in-depth understanding of the computational aspects of fluid dynamics in order to obtain accurate and satisfactory results, a new generation of CFD software is considerably more user-friendly. Envenio believes that CFD tools should complement the work of users rather than adding barriers. EXN/Aero is generally easy to use and a range of training and support options are provided. For those with no prior experience, the Discovery Project or Onboarding Program can prove useful.

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There remains a lack of understanding of the value CFD can bring to designs. Higher quality results and an easier parametric sweep to assess best design parameters would address this issue. As a responsible vendor, our team are always working to educate and train users on EXN/Aero, as well as raising awareness of simulation among the BIM communities to raise awareness of its benefits and use.


Of course, there may still be times when a business looks to outsource CFD simulation projects. This could be due to a lack of resources or expertise in-house, no time or desire to learn the software, a particularly busy workload and small team, or a one-off simulation need. Advantages of utilizing engineering services of a consultant include:

  • Benefit from the advanced expertise and knowledge of a specialist.
  • Engage a different perspective and fresh ideas that could prove hugely useful in a project.
  • May prove more financially efficient if for a one-off requirement.

As mentioned earlier in this section, Envenio's Discovery Project is a great way cost-effectively outsource a CFD need while still staying integral in the overall direction of the project. Our engineers run the simulations for you, returning data, images and conclusions to you once complete. 

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Previously, businesses have been reluctant to adopt simulation due to the lengthy licenses involved. Modern, cloud-hosted tools can be accessed on the fly in line with business requirements - ideal for SMEs and freelance consultants. 



During The Pitch Process

Whether pitching to investors or potential clients, the integration of simulation tools during the pitch phase can increase chances of success. Being able to include the latest high performance tools in a pitch can instil greater confidence in your ability to meet a deadline, allow you to keep up with the competition, stay on budget and exceed expectations.

During The Design Process

Complex HVAC systems increasingly require a more thorough understanding of cooling, hydraulics, and other fluid-flow issues. Performing comprehensive computational fluid dynamics (CFD) analyses early in the design phase is crucial to ensuring that complex mechanical products and systems perform as intended. In many ways, CFD simulation is bridging the gap between architecture and engineering.

Modern tools like EXN/Aero are removing traditional cost, time and power barriers, enabling HVAC engineers and designers to utilize the benefits of simulation during the conceptual and early design stages. This cost-effective automation means users can run a succession of ideas on a design without risking the project deadline or budget, in addition to reducing typical simulation times associated with traditional methods.

EXN/Aero makes it easy to carry out 'what-if' tests, rather than having to create multiple expensive or time-consuming prototypes. Multiple variations can be carried out and design options can be assessed before making a final decision with a greater degree of confidence. Here's why you should be using CFD simulation in your next building project.

The table below, taken from an Aberdeen Group survey, shows the impacts of not using CFD simulation during the design process.


After The Design Process: Validation & Optimization 

Using CFD For Validation/Optimization of HVAC Design Parameters

CFD simulation can still prove useful after a system has been designed and installed. Read more about the role of CFD in HVAC system optimization.

The effectiveness of an HVAC system can be tested by tools like EXN/Aero to ensure it meets intended requirements and is fit for purpose. Where gaps in efficiency occur, finer details such as location and number of diffusers and exhausts, temperature and flow rate of the supplied air etc can be optimized and adjusted. In addition, simulation can help to ensure a system is working only as required, saving energy costs, cutting carbon footprint, and potentially reducing incidences of system fatigue and failure.

Modification Of Malfunctioning HVAC Systems

Where an HVAC system malfunctions, CFD simulation tools can inform design modification through analysis. Subsequent modifications can then be further simulated without making costly physical models. As a result, any kind of malfunctioning HVAC system can be mitigated for improved performance and better HVAC within a building. Being able to highlight and fix system malfunctions prevents premature replacement and potentially saves money and areas of system redundancy.

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Building Information Modelling (BIM)

The use of Building Information Modelling (BIM) tools has increased over recent years. a trend that has changed the working methods of the Architecture, Engineering and Construction (AEC) industry. At present, global BIM guidelines vary, but countries such as the United Kingdom are working to increase its widespread adoption through mandatory BIM Level 2 compliance for all building projects.

BIM has played an essential role in increasing collaboration among multi-discipline professions, making cost savings and reducing timeframes, facilitating smarter construction and fabrication, and facilities management. Used as part of a wider execution plan, BIM is essentially a collection of all data and information about a particular building throughout its entire lifespan.


CFD Simulation & BIM

Integrated BIM-compatible computational fluid dynamics (CFD) can play a key role during the conceptual design, detailed design, and analysis phases of the BIM process, providing further information and insight into a particular structure. This is especially the case when it comes to complex HVAC scenarios.

Despite the advantages provided by CFD software applications, they are not always fully integrated within the BIM process.  A number of contributing reasons are at play here including:

  • A perception remains around the complexity of CFD and its results, with many thinking CFD tools are purely for engineers.
  • CFD is still not fully understood by many, so architects and designers may be reluctant to use simulation tools.
  • The cost of traditional CFD resources have made running simulations expensive.
  • More complex simulations have traditionally taken too long to produce results.
  • Complex software tools have made the learning curve too steep or time-consuming.
  • Engineers and architects are working separately rather than collaborating.

BIM for Dummies points out that the real value proposition is in the digital model - having a data-rich model at the end of the project which can then be used for the ongoing maintenance over the lifecycle of the building. The book's author points out that this is also where the real cost savings lie, rather than in the design and construction phase. 

Vendors like Envenio are placing simulation tools in the hands of architects, consultants and designers earlier in the design process, making the conceptual design, detailed design and analysis phases more effective and efficient. This effectively brings simulation modelling into the heart of the process, allowing input from those involved in critical phases of a building lifecycle and resulting in more valuable data being generated.



Option 1 - Outsource your CFD simulations

Perhaps time is tight and you don't have time to use simulation tools, yet still want to experience the benefits? Our engineering services have been designed to provide the benefits of CFD simulation even when experience or resources are lacking. 

With the Discovery Project, our experienced engineers will execute the project for you, working to agreed project objectives. You just tell us what you’re looking to analyze or visualize and we will prepare what you’re looking for. You'll receive all the visual data (2D, 3D images & animations) as well as full engineering data, once the project is complete. Click the button, or fill in the form below to discover the benefits.

Option 2 - Learn how to run CFD simulations with Onboarding

With the Onboarding Program, our engineers will train and support you through your first simulation setup, ensuring you get the most out of the platform, whether new to CFD or using the platform for the first time. We'll help you to mesh, set up, simulate, and post-process to achieve and evaluate the best results of an active project, so you'll still be able to exceed expectations of clients and stakeholders. Click the button, or fill in the form below to explore onboarding.

Option 3 - Schedule a FREE DEMO of EXN/Aero and get started

To find out more about how CFD could help you and your business, why not schedule a free demo with one of our engineers? The demo is a great way to see our platform in action, and to explore how it could help you and your business with HVAC simulations.


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