First things first. How did you build up the network?
I first heard about COST in 2008, while working at the Dublin Institute of Technology. I was analysing solar energy technologies with a focus on the overlap with thermal energy storage. We needed a better understanding before pitching our FP7 projects ideas, so that was when the Head of Research in Engineering, Dr Marek Rebow, introduced me to COST. It was a perfect opportunity to bring together all the experts on materials, modelling and renewable energy systems to discuss our work building on an interdisciplinary approach. This was excellent in terms of expertise and development – also the impetus for the COST Action.
How did this new interdisciplinary collaboration help you overcome the COST Action’s challenges?
We mainly looked at increasing energy efficiency in renewable energy systems buildings, which consume around 40% of the total energy in Europe. We were working on ways to reduce that. We looked at renewable energy technologies and noticed a clear need for improvement, since their efficiency levels equal or are even lower than our fossil alternatives. By using thermal energy storage, we can try to overcome some efficiency losses. By incorporating thermal energy storage with renewable energy storage, we are able to use more of the free energy available. We can also use thermal energy storage for a range of different applications – the materials we are investigating work in different temperature ranges, which is why they can be used to control temperature in various applications. We were trying to see how we could use the wasted heat energy in phase change material, store it and reuse it in an application for the building itself.
By researching new materials and new modelling techniques, we were trying to improve renewable energy storage efficiencies. The engineers engaged with materials experts to define which temperature ranges and what type of materials we needed. This also helped us understand the difficulties in materials’ synthesis and in developing the application itself, i.e. the technology.
What about market and regulation challenges?
We are still striving to tackle regulation. Some countries have building regulations that do not allow for the use of these materials. To counter this issue, we tried to undertake some standardisation of measurement of phase change material. Round robin tests on characterisation of materials were undertaken and showed different answers depending on the technique. We tried to standardise some materials-related methodologies. Researchers in Switzerland were looking at fire regulations, trying to determine their effect. Technology is proceeding and knowledge is growing, but there is a gap towards applying it directly in materials. We do have some products but they are usually encapsulated material products. We have not solved all the challenges just yet.
You mentioned standardisation as one of your COST Action’s aims. What else did you aim for?
The main aim was to develop new materials for renewable energy storage applications in terms of heating and cooling, particularly renewable applications. This did not necessarily mean coming up with new modelling techniques, but more accurate ones, by finding ways to incorporate phase change materials or thermal energy storage processes into software readily available. That way building specifiers can model of thermal energy storage easily and can determine if a certain application was useful. There are very different temperature differentials between various sections of these materials, but if we want market uptake we need a very simplified method so users can quickly determine their usefulness. We developed a handbook for architects and engineers offering an introduction to materials and where they have been used in renewable energy storage applications.
What was it about defining better techniques that you found most difficult?
The interdisciplinary interaction allowed by COST Actions proved most challenging: getting the conversation going between chemical, mechanical, civil engineers, chemists and physicists from 31 countries, half of which were Inclusiveness Target Countries (Bulgaria, Croatia, Czech Republic, Cyprus, Estonia, Latvia, Lithuania, Malta, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Türkiye). They were not used to working in such an interdisciplinary way. Getting everyone to collaborate would mean determining what technology was needed on the application side, what the temperature range was, what specific heat capacity was required for these types of applications, the melting range and communicating these details to experts in materials field.
This dialogue would not have happened before the COST Action: being able to explain to materials experts what is best in the application context and the application experts understanding the limitations behind materials. Everyone was modelling theoretical systems trying to design from currently available materials, which were not always the best. In the end, some materials researchers were looking at thermal conductivity, a different area they hadn’t focused on before.
Using a phase change material means heating the material to charge it, the application is usually in the storage of its latent heat but it is very important that the material is discharged to allow this cyclical process to continue.
The material’s conductivity is important in defining how fast heat can travel through the material. With current PCM they often have a low conductivity and this is still a challenge that researchers are working on. We were able to identify all these difficulties, and this is how we kicked off a number of FP7 projects, a Marie Curie network and a Horizon 2020 project.
We were also looking at social acceptance – the technology is there but people are not using it. We looked at better ways of communicating this so that people would start installing these systems. Current materials are difficult to retrofit, and that is costly. Products, however, are not commercially available yet. Materials are, and they can be integrated in wallboards for buildings, but products already integrated in the buildings or in the RES are scarce.
A company spinning off from the COST Action produced The Warmer Wedge by Dr Mick McKeever at the Dublin Institute of Technology. It is a package placed around people’s water tank at home, replacing the existing insulation around the tank. Dr Mick McKeever stated: “The Warmer Wedge system makes it possible to heat all the hot water needed daily at night. It uses phase change material to absorb and hold heat and the product’s novel design maximises the transfer of heat from tank water to PCM and back again.”
What are the COST Action achievements you are most proud of?
We managed to accelerate and advance phase change material research with RES. The COST Action was the start for many people and it made researchers look at materials and applications in broader context. It also helped fund several research projects nationally and internationally. And the research continues beyond the COST Action.
What is more, one of our Working Group leaders, Prof Luisa F. Cabeza from University of Lleida, just got awarded Horizon 2020 funding for a PhD network in the area of thermal energy storage. INPATH-TES is made up of a network of universities some collaborators from the COST Action as well as industry. It will enable students to get joint PhD TES qualifications from different universities.
Did your COST Action help you secure the ERC Starting Grant?
The COST Action focused on thermal energy storage, while my ERC grant is focusing on the solar technology part of the sustainable energy generation, which will lead to building integrated solar devices. The COST Action gave me a chance to meet other experts, look at the small-scale buildings aspects, and helped me understand how we can integrate these renewable energy systems. This is precisely one of the ERC grant focuses: bringing small-scale technology into building facades. The COST Action was ideal for thinking through some of the larger issues, which helped through the evaluation of the project proposal.
Were there early career investigators involved? How did you get them on board?
I was an early career investigator myself, as Chair of the COST Action, so my objective was to engage all the others. When young investigators were given the opportunity, they worked extremely well. COST encourages everyone to participate.
Did you have any particularly successful training schools or short-term scientific missions?
I found short-term scientific missions particularly useful since they can kick-start collaboration. We started small on experimentation (10x10m) and we looked at characterising a large (1x1m) solar panel system. A student went to the University of Ulster and used the solar simulator there. We then sent the system for tests in Greece, where we did comparisons with local systems. We were able to go from laboratory scale to a real application we developed.
Where do you go from here? What are your long-term plans?
I am now supervising a number of PhD students. Graduating them is very much key to sending the next generation of specialists into the workplace.
As part of the ERC project, I am investigating ways of using diffuse solar radiation in northern latitude climates as well as improving solar device efficiencies globally through luminescence. Through this work achieving real building devices is the main deliverable, rather than laboratory scale.
As for the COST Action, a lot of us are continuing collaboration. I recently participated at a meeting on building integrated solar thermal systems, held by COST Action TU1205. The Chair had also started his introduction to COST through TU0802. One of the main advantages of COST is that researchers develop a long-lasting network of expertise and colleagues as well as friends!