Microlight3D Awarded Funds to Enable Radiative Cooling Concrete with 3D Printing

As industrial society attempts to transition to more sustainable means of operating, there are countless endeavors underway to modify our existing ways of living to have a less negative impact on our ecosystem. One interesting project involves the development of concrete that could allow buildings to cool down naturally. To pull it off, the MIRACLE consortium, made up of five universities and Microlight3D, is relying on 3D printing at the nanoscale.

Urban environments are notorious for the heat island effect that generates extreme temperatures during summer months, a trend that is expected to get worse as global heat and human populations increase. If the powers that be want to continue expanding cities, they will want to address this problem. For that reason, there are a number of projects underway to reflect the heat generated by buildings back into space in the form of infrared radiation, a process known as radiative cooling.

Microlight3D’s smallest Millennium Falcon in the world at only 0.1 millimeters long. Image courtesy of Microlight3D

Microlight3D is a French manufacturer of maskless lithography for 2D printing and two-photon polymerization for 3D printing of submicron objects. On June 15, it was announced that the firm had been given the FET-Open European funding award to develop microstructured concrete. The project involves 3D printing molds rigid enough to be used for concrete, but with the sufficiently high resolution needed to create microtopographies that will enable new forms of concrete elements.

“By using microstructured concrete, buildings will be able to cool down naturally and thereby reduce the ‘urban heat islands’ that build up in cities during summer heatwaves, which can make these spaces unbearable,” said Denis Barbier, co-founder & CEO of Microlight3D. “This structural building material, which can cool down by itself, will also reduce the energy consumption used for air conditioning and benefit the climate by lowering CO2 emissions.”

With the concrete formed using these unique molds, it will be possible to insert microfibers within the microtopographies to create a “photonic metamaterial” that can convert the sun’s heat into infrared wavelengths that are then projected back into the atmosphere. In turn, buildings made from this material would theoretically be able to expel heat back into outer space without using additional energy.

Denis Barbier and Philippe Paliard present the 1st micro-structured concrete sample. Image courtesy of Microlight3D.

The MIRACLE team has pointed out that photonic concrete has applications beyond building construction:

“While the application of radiative cooling in buildings is probably the most important application, the concept of photonic meta-concrete transcends this application. Solar cell technology, for example, requires new materials/devices to cool the solar cell configuration. Here, the challenge would be to find new concretes that combine high transparency with sunlight with high emitting capacity in the atmospheric window. Similarly, MIRACLE’s technology pays attention to the infrared (IR) region of the electromagnetic spectrum, but the concept of photonic Meta-concrete provides an exceptional basis for new applications in the field of telecommunications in other regions of the electromagnetic spectrum (e.g. technologies in the GHz and THz).”

The project will take place over the next four years, led by Spanish Superior Council for Scientific Research (CSIC – Madrid), as well as members of the MIRACLE consortium: Technische Universitat Darmstadt, of Germany; Universidad Publica de Navarra, of Pamplona, Spain; Fundacion Tecnalia Research & Innovation, of San Sebastian, Spain; Katholieke Universiteit Leuven, of Belgium; Politecnico di Torino, of Italy; and Microlight3D.

Given that Microlight3D is focused on the small scale, one wonders how they will be able to increase the output of their process to tackle such large elements as concrete slabs. Perhaps a very large vat could be used to create the massive molds, but there will be the need to spread the laser pulses across that large area, potentially slowing down or increasing the complexity of the process greatly. Additionally, there will be issue of inserting the microfibers into the concrete, which will need to be automated if construction is to be performed at a reasonable pace, as well.

Nevertheless, there are numerous other ecological issues associated with concrete that will need to be dealt with, as well, not the least of which are the massive emissions used to produce concrete. About 40 percent of this comes from the energy used to manufacture the material and 50 percent from the calcination process. While the former can be addressed by powering production with renewable sources, the latter would require the use of recycled concrete, which does not yet have a sufficient infrastructure in place.

It’s also necessary to consider the energy required to produce this new form of concrete and how it compares with traditional building materials. Simpler solutions may involve painting roads and roofs white or adoring cities with rooftop gardens, in addition to rewilding as much as possible.

As we learned in our interview with a housing expert, technological solutions may not be as powerful on their surface as economic, political and social solutions. That isn’t to say that we shouldn’t be researching more sustainable materials in general, which we should, but that they are longer-term answers to immediate problems that may be better solved by utilizing existing buildings to house the growing population.