Inspenet, September 24, 2023.
Conicet and the Catholic University of Córdoba have developed and patented a modular system intended for the creation of biosolar roofs. These innovative roofs generate electricity by combining solar panels and native vegetation, with a simple and low-maintenance assembly system.
The purpose of this creation is to reduce the energy demand of a building and provide various ecosystem benefits to its occupants. In the coming months, they plan to install the first full-scale biosolar roof at the Padre Domingo Viera agrotechnical school, located in Alta Gracia, Córdoba. In addition, this project has the participation of experts from the Arteaga Technology Center (CTDA) and the Dovis & Federico design studio.
“The good thing about assembling green roofs with solar panels is that it is a partnership that benefits both. On the one hand, the humidity of the plants generates an environment that makes the panel have greater electrical performance. On the other hand, the panels shade the plants, protecting them from exposure to climatic conditions such as winds and solar radiation that are greater when being on a roof. Added to this is the energy savings obtained with the use of the panels,” explains the doctor in Agricultural Sciences Lelia Imhof, CONICET researcher at the Institute for Research in Natural Resources and Sustainability (IRNASUS) and coordinator of the team.
Researchers began exploring this topic in 2011, when they began the development of a modular green roof system, where each module covered 1 m 2 . Later, after studying the integration of green roofs with photovoltaic panels that were being developed in other countries, they chose to adapt this technology to the conditions of our territory.
Electricity through biosolar roofs
“Instead of using layers, we use a UV-resistant polyethylene tray, which fulfills the role of all the layers together. The advantage of this is that if a crack occurs in the ply system, the entire roof must be dismantled. On the other hand, with this system, you can lift only the area where you have the problem,” indicates the researcher. They also made adaptations to the trays so that they can retain moisture for longer, thinking that it can be used for arid and semi-arid climates such as the Cordoba winter.
This system offers a variety of ecological benefits, including carbon capture by plants, rainwater retention, shown in research to reach up to 70%, and energy saving efficiency, which has been measured within the university and reaches up to 40%. The substrate layer has a depth of around 15 centimeters, and the plants used in this system are native species selected by the researchers after various tests. These native plants have a greater ability to survive in adverse conditions and do not depend on fertilizers or large amounts of irrigation, which adds another advantage to the system by requiring minimal maintenance.
“The maintenance of the green roofs that we work on is almost zero. The vegetation is ready for that. Our climate is quite arid and from March to October it does not rain, so we add drip irrigation, which is minimal for plant maintenance, but does not require weeding or fertilizers. And the panel only requires cleaning like any panel, which is recommended once a year,” says Imhof.
About the development of biosolar roofs
The development of the biosolar roof project was carried out in several phases. Initially, researchers focused on drawing up the plans and designing the system. Subsequently, they proceeded to build a pilot prototype of four square meters of green roof with a solar panel on top. For these two stages, they received financing from the Agency for the Economic Development of the City of Córdoba (ADEC).
Later, they participated in the call for Federal Innovation Projects (PFI), promoted by the Federal Council of Science and Technology (COFECyT) and the Ministry of Science, Technology and Innovation (MINCYT), and managed to obtain a subsidy for the installation of biosolar roofs at the Alta Gracia school. In this case, 40 square meter green roofs will be implemented with ten solar panels on top. During the first half of the current year, the acquisition of materials, the adaptation of the roof and the construction of the necessary parts were carried out, and the installation is planned to be carried out in the coming months.
The researcher mentions that the developed technology can be shared both with public sector entities, with which they have collaborated on multiple occasions, and with private companies. The modular green roof system already has a patent held by CONICET and the UCC and they are now in the process of registering biosolar roofs with a view to exploring transfer and commercialization opportunities in the future.
Regarding the costs associated with this type of systems, Imhof explains that the initial investment can be recovered through lines of credit backed by the State, which offer lower interest rates for construction projects that incorporate the generation of clean energy. “One of the reasons why we added the panels is that it allows access to that type of credit, which perhaps does not exist for green roofs. Furthermore, there are more and more (property) developers who, although they are not required to install these systems by any ordinance, do so anyway because of the energy and environmental benefits they entail,” he states.
Currently, researchers are busy in the process of propagating the plants in the university facilities and plan to carry out the implementation between the months of October and November. “Once installed, the system will provide power to the school. We ask the company that installs the panels to also make the connection to the network so that the school can use it. And we are going to take advantage of the launch to see how it works, measure aspects that interest us a lot, such as efficiency and pollination, and see what adjustments we can make,” concluded Imhof.