Currently the algae are being used to feed livestock, produce textiles and biofuel. These plant organisms are also being used in construction as an environmentally responsible solution. The Professor of Architectural Composition and Director of the Master’s Degree in Advanced Project of Architecture and City of the UAH, Mª Rosa Cervera, explains the characteristics of this new element.
How is algae used in construction?
Research on algae is a field of growing interest, development and experimentation in the world and is presented as a valuable alternative to meet the needs of humanity in the 21st century. Introducing living matter as part of construction is a promising path that is now beginning its journey.
Building enclosure surfaces are increasingly versatile places to make their enclosure function compatible with others such as producing energy and capturing CO2. This vision of multifunctionality of architecture has a double contribution since it benefits society by using architecture for a function of energy and environmental value, which adds to its usual constructive missions, and benefits construction by providing greater isolation of the building. The great innovation of the project is the combination of two fields, the constructive and the biological, in a highly disruptive and unique way to achieve a sustainable city, with a holistic vision of energy, by cultivating algae in architecture.
In this way, a green technology, which provides extraordinary aesthetic value, becomes a global awareness, making the R & D & I investment for a better future tangible.
What is its function in a building?
Architectural photobioreactors consist of water conduction systems with microalgae, nutrients and CO2, whether these are closed tubular, sandwich laminar or open pond, always with materials that allow light to pass for the photosynthesis process (glasses, methacrylates and various plastics, EFTE, etc.) and with the particular characteristic of being integrated or having as support the construction surfaces, both of buildings and pavements of the city or urban elements.
In short, it is a novel reinterpretation of industrial algae photo-bioreactors to turn them into ‘skin’ or architectural construction surface. That is, spend the ‘back-stage‘productive to’front-row‘, converting what has so far been industrial into a new type of exterior layer of the architectural enclosure with important added values at the energy and environmental level.
What benefits do they provide in the building?
The cultivation of microalgae in architecture, on the one hand, contributes or produces and, on the other, reduces or minimizes. What it contributes is biomass, biomass that can be used to obtain various products depending on the cultivation conditions and its subsequent treatment. Micro algal biomass can be the basis for the production of biogas and also electricity through cogeneration; it can be transformed into value-added products, such as medicines, cosmetics and human and animal nutrition; It can be used as a biofertilizer and bio-stimulant in agriculture and, finally, with a more elaborate process and still not very competitive, in biofuel.
The fundamental subtractive or minimizing action of algae and the one that distinguishes this technology from the rest of renewable energies is its ability to capture CO2 and its sink effect, a subject on which we are deepening our research. Other qualities to be taken into account are those that refer to the ability of algae to purify water, thus contributing to its cycle, and for its help in saving energy by insulation and by thermal regulation as a living organism.
All this makes architectural photobioreactors already today a real, economic, ecological alternative, with a very valuable image, which is competitive for medium and large spaces, being especially suitable for two market segments such as public institutions and large companies.
What type of algae are used?
We are currently working with two common species such as algae Spirulina and the seaweed Scenedesmus, since both grow well in our climate. The first is grown in the spring and summer months and the second in the autumn and winter months. We are currently designing various photobioreactor models and proceeding to calculate the harvested biomass and captured CO2, all based on the variables of temperature and light, pH, characteristics of the algae species and their concentration and the conditions of the Used materials. The next, and immediate step, is the construction of the models for the verification of the data obtained.
In the near future, using this technology will be an efficient way to capture CO2 and increase the production of bioenergy and other valuable products. And from the point of view of architecture, the incorporation of photobioreactors to it will be a creative way of introducing nature so that cities become more ecological and go from being consumers to being energy producers, inverting the current unsustainable model.