Every successful project starts with a framework. A vision statement. A blueprint. The editors of Engineered Systems are proud to present The Blueprint — a monthly Q&A interview with HVACR engineering’s leading voices. These one-on-one discussions will examine the trade’s history, current industry trends, the factors shaping the sector’s future, and more.

Exergyn, a creative clean-tech company, is a pioneer in the commercial-scale application of shape memory alloys (SMA). The company designs and develops SMA core technology to enable its global partners to transform their product offering, without compromising on cost, size, weight, or efficiencies.

In this interview, Herb Woerpel, editor-in-chief of Engineered Systems, sat down with Kevin O’Toole, co-founder and managing director of Exergyn Ltd., who discusses SMA technology, its use in America, and abroad, and much more.

Engineered Systems: Kevin, please take a moment and introduce yourself and Exergyn.

O’Toole: I’m Kevin O’Toole, co-founder and managing director of Exergyn Ltd. I’m a mechanical engineer with an honors degree from the Technical University of Dublin, Ireland, and I hold a Ph.D in shape memory alloy (SMA) applications. I have spent the last 15 years working with SMA in the energy space, founding Exergyn in the process. Exergyn focuses on the use of SMA in solid-state thermal management applications — cooling and heat pumping. Our central innovation is our highly efficient solid-state “SMA stack.” Our platform technology can be adopted for various applications across the HVACR industry as well as the automotive and aerospace industries. 

Engineered Systems: Exergyn touts SMA as the “future of sustainable energy.” Seeing that you are a doctor on the subject, can you please introduce us to SMA and explain how it works?

O’Toole: SMA is a unique metal alloy that exhibits two unique behaviors — the shape memory effect and superelasticity. Primarily made up of nickel and titanium, the alloy has two distinct metallic states — austenite and martensite. Our thermal management solutions are based on superelasticity, where an external force — typically generated by a hydraulic ram or electric actuator — compresses the SMA material. This results in an internal phase change from austenite to martensite. In doing so, the material releases a large amount of latent heat. The reverse is true during unloading in that the SMA absorbs a large amount of latent heat. This behavior mimics that of a refrigerant gas, but we are doing so with no negative impact on the environment. This is quite unlike refrigerant gases which are the leading contributor to climate change. Since both our phases are metallic, we don’t suffer leaks and are thus global warming potential (GWP)-free. (For reference, one unit of GWP is equivalent to the warming impact of one unit of CO2. Most refrigerant gases have GWPs in the hundreds or thousands, and so are extremely bad from a climate change perspective).
The inherent advantage of SMA is that we are changing the ratios of the chemical elements in the matrix, meaning we can optimize the material for different applications. So, an SMA stack for refrigeration looks almost identical to an SMA stack for, say, a district heating application, with the only difference being the chemical ratios in the microstructure. This means we have a very high commonality of components across the full spectrum of applications, quite unlike the current HVACR landscape.

Engineered Systems: Is SMA expensive to own, operate, and maintain?

O’Toole: Not at all. SMA is made from nickel and titanium, mostly, both of which are common materials and relatively ubiquitous. Our unique approach means we can use the lowest grade of material possible, which keeps the system costs as low as possible in terms of Capex. We have had independent third parties assess our system manufacturing costs at high volumes, and they expect us to be in line with today's traditional cooling systems and, in some cases, significantly cheaper. From an opex perspective, we have demonstrated the equivalent of 40-plus years of operation in accelerated testing of the SMA, which will ensure maintenance of the SMA stacks is kept to a minimum. The balance of the plant is all made of standard items and engineering materials and, as such, is subject to standard maintenance and its associated costs. 

Engineered Systems: What applications is SMA best geared for?

O’Toole: SMA found its initial home in the biomedical arena. Heart stents, dental braces, and even eyeglasses, which can be deformed and return to their original shape, are all examples of SMA in biomedical products. They are also becoming more popular as actuators in the automotive arena on the back of recent advances in manufacturing technology. However, I believe that the biggest impact of SMA will be felt in the energy space where Exergyn operates. It offers the perfect alternative to refrigerant gases and can match performance at the right cost.  There exists no other material or system today that I am aware of, other than SMA, that can achieve this — and at zero GWP. My hope and expectation is that SMA will lead the way in the impending cooling revolution. 

Engineered Systems: How should consulting/specifying HVACR engineers consider including it in their commercial facilities?

O’Toole: Whilst we are still in development at the moment, the design philosophy we use is to make it as easy to retrofit as possible. We typically operate two heat exchangers (equivalent of the evaporator and condenser in a vapor compression system). In effect, the vapor compression loop and its components, such as the compressor and expansion valve, can be swapped for the solid-state loop and its components. Such components, other than the SMA stacks and their housing, are the hydraulic pump and circuit, a couple of fluid pumps, and the valve control system. It’s a simple system. Our system is designed to operate to standard conditions, such as Eurovent, so specification should be similar to traditional systems in that sense.  

Engineered Systems: Are there any drawbacks or negatives to the SMA technology?

O’Toole: Like all new technologies, there will be inevitable engineering challenges as we seek to optimize the platform for a multitude of different applications. The challenge has now shifted to considering how to roll our systems out as fast as possible to help remove refrigerants from the environment as quickly as possible. Being a new technology, this will come with some logistical difficulty, as the supply chain is not yet fully developed for very large volumes of SMA. With time that will change and with legislation driving a change in the approach to cooling, that will speed it along. But, as of today, that’s the main drawback as I see it. 

Engineered Systems: Fossil fuels are still largely favored over renewable energy options despite their lower costs and effectiveness. Why is this so?

O’Toole: In my opinion, it is a correlation of both convenience and apathy. Our daily infrastructure has evolved over 100 years to make fossil fuels convenient and easily accessible for everyone. Access to renewables is changing for the better and momentum is building now more than ever to bring online more renewable technologies and resources although challenges remain. In parallel, the slow-moving nature of climate change brings about the ‘boiling frog’ effect, where people don’t tend to notice small differences and thus downplay the impacts until it's too late. This allows for apathy to develop, which can cause some to reach out for the easiest, most accessible solution. As such, the commercial pull still isn’t quite there amongst the majority, but that is changing. 

Engineered Systems: What will it take to reverse this trend?

O’Toole: Legislation and education. Legislators in Europe are moving quickly now and have identified the issues and are moving to ban key impactors, such as high-GWP refrigerant gases, for example. This will lead to their eventual removal by force or through taxing them out of the market. In parallel, a continuation of the educational push to ensure that the general population is aware of the impact of their choices on the environment will help but alone is not sufficient. The silver lining of the recent heat waves across North America and Europe is that people are waking up to the fact that this isn’t normal and is driven by our lifestyle. This will further chip away at the apathy, and, perhaps, more informed choices will fuel an acceleration in the uptake of renewables. Hopefully it won't be too late. 

Engineered Systems: Exergyn is located in Ireland, and our magazine/audience is largely based in the U.S. Can you speak to the popularity of SMA in Ireland, and if/when we can expect to see this technology grow in popularity here in the U.S.?

O’Toole: I wouldn’t say SMA is inherently popular or unpopular in a specific locality. It’s a new technology entering field trials, so it's not a common sight presently to gain any such status. Even at mass deployment, the reality is that most end users likely won’t care about what the system is made of — so long as it works and maintains a desired, comfortable environment. However, key metrics, such as cost and performance, would certainly be noticed. Similarly, with continued awareness of climate change, I would expect a clean system, such as ours, to be significantly more attractive on that basis alone. We would hope to roll out such technology across the U.S. in the next few years with ambitions to change the trajectory of global warming through eliminating refrigerant gases completely over the next 30-40 years.
Since SMA is zero-GWP, it won't be impacted by any impending legislation. The end result is that our system will maintain performance and cost in line with today’s standards, while traditional refrigerant-based systems will not. Such systems will need to shift to using alternate refrigerant gases, which are neither as efficient nor as safe, with an associated increase in cost resulting from efforts to mitigate these issues. 

Engineered Systems: Are there any last words of advice you’d like to leave our audience with?

O’Toole: I truly believe that traditional HVACR today is probably about as good as it will get for that particular technology. The impact of legislation to clean up the industry will be felt over the next few decades and will be noticed through higher costs of operation or decreasing performance. This will lead to a revolution in space comfort within the next decade or so as end users look for alternatives. It’s inevitable — and the bare fact is that we really need to change our approach if we are to save ourselves from the worst excesses of climate change. 

Engineered Systems: What’s the best way for readers to connect with you or Exergyn?

O’Toole: Further information can be found at www.exergyn.com or on our LinkedIn company page www.linkedin.com/company/exergyn.