Over recent years we have seen significant growth in infrastructure and construction across our major capital cities in Australia and New Zealand, and in turn there has been an increase in the use of CFD and other CAE simulation to help get building designs right the first time, before any concrete is poured.
This is true across both the large multidisciplinary consulting firms, as well as a growing band of niche consultancies who often specialise in particular areas (such as sustainability linked with indoor thermal comfort, or car park design to meet increasingly stringent regulations). As a result, here at LEAP Australia we’ve also observed a growing number of graduate engineers now seeking a career in HVAC simulation, as well as enquiries from experienced simulation practitioners who are looking to move into construction- and infrastructure-related projects.
So let’s take a moment to review the 4 key applications that CFD engineers are working on within the HVAC/Construction industry:
1. Ventilation & Thermal Comfort
The sustainable design of a complex heating, ventilation and air conditioning (HVAC) system will aim to maximise thermal comfort by considering details such as:
- room temperature,
- room humidity,
- expected occupancy levels and body heat,
- mean age of air within an interior space,
- ventilation of pollutants such as CO within a car park,
- relationship with the external environment including solar loading and shading, and
- heat loss through the building envelope such as through doors, windows and walls.
By modelling the air flow, temperatures and potential pollutants throughout a building in CFD, engineers are able to iterate on their HVAC design cost-efficiently and can quickly consider all key design tradeoffs so that they can arrive at the optimal HVAC setup for a specific building project (considering both cost, comfort and energy efficiency).
For consulting companies and property developers, the business benefits include faster approval of proposed building designs, reduced risk of project cost blowouts, and on-target construction timeframes by avoiding the need for re-work or last minute design changes.
For existing users of CFD, here is a previous blog showing an example of how to calculate the mean age of air within an office or other internal environment.
Advances in GPU-powered CFD solver from ANSYS with the advent of Discovery Live have now also provided architects and HVAC designers with a new, powerful tool to collaborate using real-time simulation – imagine a situation where you can brainstorm proposed design changes to an HVAC design without “handing it over to the analyst (for a few days or weeks)” but instead making changes on-the-fly during your concept/planning meeting and seeing the results update instantaneously:
2. HVAC Equipment Design
Design of equipment for heating, ventilation and air conditioning (HVAC) is a mature industry and so there is increasing pressure to differentiate OEM products by increasing their energy efficiency while concurrently reducing manufacturing costs. CFD simulations allow design engineers to assess key product performance metrics such as noise levels, energy efficiency and reliability across a wide range of HVAC equipment such as:
- Air cleaning equipment
- Air conditioners
- Air handlers
- Burner design/boilers
- Heat exchangers/coils
- Heating equipment
- Pumps/blowers, fans and compressors/exhausters
By simulating the performance of HVAC equipment in a virtual prototype subject to a variety of environmental conditions and under different loads, manufacturers can avoid having to build costly physical prototypes during their preliminary design and aim to identify potential problems as early as possible (at a time in the design cycle when mistakes are still relatively inexpensive to fix!).
Equipment manufacturers are also under pressure to optimise the shape of HVAC components so that they can fit into confined spaces. Just like in the automotive industry, HVAC engineers are often working with substantial design constraints and are beginning to use CFD to help fit their components into limited spaces whilst still optimising performance (ie. minimising pressure drop within their equipment).
3. Fire & Smoke Propagation
Increasingly strict regulations govern the design of fire and smoke management systems for any new building or facility, so developers must ensure their design meets well-defined conditions relating to the:
- safety of occupants during a fire &
- structural integrity of the building.
As you would expect, a physical test of a fire scenario is extremely expensive and labour intensive, and also may require consideration of a large number of variables - so engineers are increasingly turning to CFD simulations to undertake the bulk of the legwork in their fire/smoke projects. As a fire engineer, we must first understand the physical phenomena of how fires start, propagate and impact on the structure, and how we can best simulate this physics within our CFD simulations. Once we have a well-validated CFD model, we are then able to commence systematic parametric studies so that we have considered all likely fire scenarios and are able to develop a fire mitigation system to:
- optimise emergency evacuation procedures,
- optimise placement of smoke management & firefighting equipment, and
- ultimately prevent a fire from spreading out of control within the structure.
4. Wind Engineering
We are all aware that our cities are becoming denser as developers look to build upwards rather than outwards. When approving new plans, government and planning agencies are now increasingly mindful of the effects that new buildings will have on an urban environment – no one likes walking around a corner only to be almost blown off their feet due to a wind-tunnel effect between tall buildings!
There are also compounding effects at play: designs of new skyscrapers, bridges, stadiums and landmarks also become more difficult as the surrounding environments grow more complex with each new project. Subsequently, engineers and architects must carry out more complex wind engineering analyses to help predict how a building responds to its environment and what changes it will bring to surrounding areas. Engineers in this field are primarily concerned with:
- Understanding the external aerodynamics of a building for all possible wind angles
- Quantifying structural wind loads for all possible wind angles
- Transport and dispersion of pollutants
- Impact of wind-driven rain on balconies and entrances/foyers
- Pedestrian comfort at ground level
In conjunction with carefully planned wind tunnel studies, CFD simulation provides engineers with a cost-effective and insightful tool to better understand all of these key applications while also providing authorities with suitable data to complete environmental impact statements and assess whether new designs meet regulatory guidelines.
In each of these key applications across the construction industry, the use of a virtual modelling approach with CFD provides engineers and designers with the right tool to:
- evaluate and compare a range of options quickly and efficiently,
- reduce the risk of faulty construction and increase the probability of project completion on time and within budget, and
- satisfy all regulatory requirements relating to safety and sustainability.
Do you have a HVAC or construction project that would benefit from clever use of simulation to troubleshoot or optimise your design? Get in touch with LEAP today for a no-obligation meeting to discuss your specific project requirements.