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As of October 2024, Roel Loonen has joined the EIRES Management Team. The Associate Professor at the Unit Building Physics and Services of the Department of the Built Environment leads the focus area Energy Transition in the Built Environment, together with Lenneke Kuijer. ‘The research in our focus area is crucial to realizing the energy transition in a way that appeals to society.’

Ever since he was in high school, Roel Loonen has wanted to make buildings comfortable for the people living or working in them. ‘Besides being solid and safe, I also want buildings to provide a good and healthy living environment. That is why I decided to enroll in what later turned out to be the final cohort of the bachelor program Building Services here at ºÚÁϸ£ÀûÍø.’ When he started studying here twenty years ago, a lot of attention was paid to saving energy without sacrificing comfort. ‘Even though that is still essential, in the meantime, the role of sustainable energy generation, storage and distribution has become increasingly prominent.’

Loonen has always been interested in developing new things, and thinking outside the box. That is why, after obtaining his master’s degree, he decided to pursue a PhD and stay in academia. ‘At university, I have the freedom to deep dive into the mechanisms underlying a building’s level of comfort, and to explore how the built environment impacts its environment.’

Adaptive facades

The golden thread in his research is the development and application of modeling and simulation strategies to provide decision support for designing buildings that combine high indoor quality with low or no impact on the environment. Many of Loonen’s research projects deal with building-integrated renewable energy technologies and so-called adaptive facades. ‘Adaptive facades are walls, roofs or windows that are able to change some of their functions, features or properties over time, to improve the building‘s performance and increase its energy efficiency,’ Loonen explains. As an example, he mentions a project he worked on together with . This company, which started as a spin-off from the Department of Chemical engineering and Chemistry, develops solar shading glass: glass that can be dimmed between bright and dark states to ensure optimal natural light conditions in the building. ‘We performed simulations to evaluate the possible energy savings and the indoor comfort experienced by the inhabitants of the building. In the end, our models help to establish the optimal amount of glass to be installed.’

Smart windows

In another project called , Loonen and his team, together with colleagues from TNO, are using the SolarBEAT facility on top of the Vertigo building to experiment with insulated glazing units that integrate solar shading with bifacial photovoltaics. These windows aim to mediate between achieving high performance in daylight and shading, thermal comfort, visual connection, and energy generation. Aside from the typical electricity generated by photovoltaics as the sun faces the front side of the solar cells, the novel contribution of these windows is that as part of the light is admitted through the window, it is reflected off the venetian blinds and redirected to the back side of the solar cell to contribute to additional electricity harvesting.
‘These types of innovations enable buildings to be constructed with a lot of glass to maximize the amount of daylight coming in, without introducing the need to install a lot of additional heating or cooling installations. At ºÚÁϸ£ÀûÍø, we use models and simulations to find the optimal balance between capturing sunlight for electricity generation and ending up with enough daylight. In addition to that, we study the effects of different configurations and control mechanisms for different types of buildings and orientations.’

Linking research and education

Loonen has been connected to EIRES from the start, since all of his research is directly linked to energy management. ‘Research wise, I am involved in the BEHeaT program, where I have two collaborative projects with Lenneke, called MIESDOC and JUST PREPARE. And when it comes to education, I am part of the interdepartmental master course Sustainable Energy Technology. As a new member of the EIRES Management Team it is my personal mission to further strengthen the links between the energy-related research and education at ºÚÁϸ£ÀûÍø.’

‘If we want to make a true impact on the energy transition, we need to look beyond the borders of disciplines,’ Loonen states. ‘We not only need to develop new materials, new devices and new systems, but we also need to build a thorough understanding of the behavior of our end users. That is where EIRES can really make a difference: in establishing connections between the different fields of research that are needed to develop technology that can successfully be implemented in practice.’

Loonen knows that realizing the energy transition in the built environment is not an easy task. ‘There are no quick fixes. In the end, we will need a combination of applications and specializations. The researchers that are united within the focus area Energy in the Built Environment have the knowledge and methods that are necessary to develop solutions that comply with daily practices. But in order for us scientists to come up with useful ideas, we need to be in close contact with the stakeholders, like municipalities, building companies, installation companies, grid operators and inhabitants. That is where EIRES plays an important role. As an individual researcher, it is impossible to keep track of all developments. EIRES both acts as a single point of entry for people from the outside, and as a funnel to collect and guide societal developments to the right area of expertise within university. In the end, it is all about collaboration and integration. That is exactly where an interdisciplinary institute like EIRES makes all the difference.’