More and more HVAC designers and consultants are using computational fluid dynamics (CFD) in the design of air conditioning systems to understand airflow and temperature distribution, and to design optimized and efficient cooling systems. In this article, we examine why simulation is so useful in the design, validation and optimization of air conditioning systems.
Using CFD Simulation For Better Air Conditioning Design
Essentially, CFD is a computational technology that uses numerical methods to solve and analyse the problems that involve fluid flows and thermal issues. Don't worry though, you don't need to be a CFD engineer to be able to benefit from simulation. HVAC engineers face a number of daily challenges. Whether trying to cool a data center full of servers, or maintain a consistent and comfortable temperature in an office, their goal is to design the most effective yet efficient systems fit for purpose.
Why Use CFD For Air Conditioning Design Work?
(1) To Optimize Air Conditioning Systems
With simulation, designers can build detailed virtual models of existing and new air conditioning units, even importing complex geometries from existing CAD designs, before analyzing airflow and heat transfer in explicit detail. In turn, they can gain a greater understanding of intakes and returns, age-of-air, and any issues with stagnation or fluctuations. Such an approach not only reduces and limits traditional inefficiencies in prototyping at the design stage, but also improves performance once a system is installed.
(2) To Predict Air Conditioning System Performance
Simulation enables designers to predict how an air conditioning unit or system will perform in a particular environment - something that is particularly useful for HVAC engineers managing client consultancy projects. The ability to predict how an air conditioning system will perform is ideal for those working in the built environment, who are looking to make choices early in the design process and potentially save costs down the line.
What Are The Benefits For Air Conditioning Design Engineers?
Overall, the benefits of using simulation for air conditioning include:
- Uptime: Designers can better understand failure scenarios and reduce areas of system redundancy.
- Operational Costs: By simulating various scenarios, optimal operational costs can be achieved.
- Capital Costs: Designers can make large investment decisions with full confidence and information.
- Maximise Available Space: Designers can optimize use of their available equipment and systems.
- Satisfy Legislation: Through simulation, designers can satisfy legal standards and legislation around thermal comfort.
Air Conditioning Design Applications
Atrium Designs, Concert Halls & Auditoriums
Thermal comfort and safety are the key reasons for adopting CFD tools in atria, concert halls and auditoriums. CFD tools help to create a uniform temperature throughout and can also be used to assist with fire safety and smoke prediction.
Operating Rooms & Clean Rooms
With contamination an ever-present concern, CFD simulation is widely used in operating and clean rooms around the world. Understanding how air flows and interacts with surgeons, researchers, patients and objects is a vital component in the safe operation of practices within this sensitive environment.
Residential & Commercial Buildings (Apartments & Office Blocks)
Keeping occupants of both residential and commercial buildings is essential to comply with safety legislation and ensure productivity. CFD tools can be used by developers and businesses to simulate such environments and create optimal conditions.
Manufacturing Facilities & Factories
Manufacturing facilities or factories are environments that require careful understanding when it comes to their HVAC systems. CFD tools can help businesses to meet temperature requirements, simulate airflow, and eradicate contamination.
Vertical Farming Facilities
The way we farm is changing. Vertical and container farming practices require optimal environmental conditions in order to meet growth outputs, and CFD tools prove a useful way in which to simulate a particular grow environment and understand the performance of existing or proposed HVAC systems.
Restaurants & Hotels
Ensuring the comfort of occupants is essential for restaurants and hotels, and as such CFD tools can help to create optimal temperatures throughout a building, simulating airflow and identifying the performance of existing HVAC systems.
Aircraft, Boat & Cars
With AC loads accounting for more than 5% of the fuel used annually for light-duty vehicles in the United States alone, it's hardly surprising that HVAC engineers are turning to CFD tools for more effective air conditioning design. Additionally, research by Mitsubishi shows AC loads to significantly impact electric, plug-in electric vehicle, and hybrid electric vehicle performance by up to 50%. Cabin climate conditioning is one of the main problems for long distance trucks during driver rest periods and is another key area of application where CFD tools can help to analyze the performance of air conditioning design allowing for crucial changes to have a desired effect.
Air Conditioning Design: Chilled Beams
The use and effectiveness of chilled beams is a particularly hot topic at present, particularly across North America. This was highlighted in a recent paper presented at the ASHRAE 2018 Winter Conference by Abdullah Karimi, of Southland Industries, Dulles, Virginia.
Diagram demonstrating how a chilled beam system works
He noted that chilled beams performance was determined by several parameters, including placement, primary supply airflow, mixed-air throw angle, and the effective rate of induced air. These combine to make the design optimization of active chilled beams particularly challenging when employing conventional one-dimensional calculations, and performing experimental tests for many design variables is cost-prohibitive.
Karimi introduced CFD as a cost-effective and accurate design-optimization tool, specifically employing large eddy simulations (LES), which – with proper flow-resolving computational grids – can give a more accurate prediction of the flow distribution. The placement of cool beams can then be decided with greater confidence. He provided a case study of a typical office space application, validating against experimental data. Read the paper here.
EXN/Aero: Accessible CFD
- Pay as you go: EXN/Aero is accessed on-demand on a pay-as-you-go model, so costs much less than you may think.
- Ditch the licenses: Access simulation software on the fly, as and when needed. No more restrictive licenses.
- Easy to use: You don't need to be a CFD specialist. Our platform is easy to use and we'll support you all the way.
- High Performance Software: You'll benefit from the latest high performance software from your laptop or desktop.
EXN/Aero: CFD Simulation In The Cloud
There's no excuse to not being able to take advantage of simulation. Envenio has created the Discovery Project and Onboarding Program to further assist those air conditioning engineers and designers without CFD experience. With the Discovery Project, Envenio executes a HVAC project on the client's behalf, returning engineering data and results according to an agreed set of objectives. With the Onboarding Program, Envenio works alongside the HVAC engineer or consultant to kick start their simulation project while training them fully on the platform. It guarantees the client is successful in using affordable simulation software tool, EXN/Aero, and minimizes the learning curve.