Salt, or sodium chloride, is a widely available and versatile substance. It has been used for centuries in various ways such as preserving local ecosystems, de-icing roads, and industrial processes. It is also commonly used as a seasoning in cooking. Despite its abundance and long history of use, there is relatively little research and interest in exploring its potential uses beyond its traditional applications.
However, salt has many unique properties such as being affordable, easily available, antibacterial, fire-resistant, able to store humidity and heat, and effective in reflecting and diffusing light. These characteristics make it a material with great potential for a wide range of applications.
One of the significant challenges in enhancing resource efficiency in the construction industry is identifying materials that can replace scarce natural resources. Could salt, with its unique characteristics, be a viable alternative? Could it be a material of the future?
While salt has potential, its tendency to absorb moisture, susceptibility to erosion by wind and water, and potential to cause corrosion to metal components used in construction, have limited its use as a building material. However, these challenges also provide an opportunity to explore specific applications where salt could be beneficial despite these difficulties.
What are Crystallized Salt Panels?
Salt is essentially a chemical compound formed by sodium and chloride ions that, when dissolved in water, separate and become surrounded by water molecules. If the water evaporates, the ions come closer together and form a lattice structure that results in the formation of salt crystals. Crystals can form in a variety of ways, from the evaporation of seawater to underground mining and chemical reactions. As the world population grows and living standards improve, the amount of salt produced as waste through seawater desalination and potash mining has dramatically increased, meaning the resource is more abundant than ever.
Crystallized salt panels are a new technology that uses salt crystals to both harvest salt and generates electricity. The panels consist of a thin layer of salt crystals on a transparent substrate, which is then exposed to sunlight. As the salt crystals absorb the sunlight, they begin to grow, forming larger and more complex crystal structures.
The process of salt crystal growth is called crystallization, and it is a well-known phenomenon in chemistry and materials science. By controlling the conditions under which the salt crystals grow, such as temperature, humidity, and the composition of the salt solution, scientists are able to manipulate the properties of the crystals and optimize their performance for different applications.
How do Crystallized Salt Panels Work?
Crystallized salt panels work by using the process of crystallization to generate electricity. As the salt crystals grow, they create a voltage between the different layers of the crystal structure. This voltage can then be harnessed to generate electricity using a process called salt-water electrolysis.
In salt-water electrolysis, an electric current is passed through a solution of salt water, causing the water molecules to break down into hydrogen and oxygen. The hydrogen can then be used as a fuel source, while the oxygen is released into the atmosphere.
One of the benefits of using salt-water electrolysis is that it is a clean and renewable energy source. Unlike fossil fuels, salt-water electrolysis does not produce any harmful emissions or contribute to climate change.
Crystallized salt panels that grow in a farm-like system:
At Atelier Luma in the south of France, a design and research lab is utilizing salt crystallization to create new applications and support the traditional local salt industry. Based at the Luma Arles campus, the team at Atelier Luma is exploring the potential of a natural, circular process for architecture and design through their unique approach to working with salt crystallization. Project manager Henna Burney shared more about the initiative and how it aims to elevate salt as a valuable material.
Since 2017, Atelier Luma has been using the salt water from the Rhône river delta, known as Camargue, to create new materials that highlight the local resources and showcase the physical and aesthetic properties of salt. Using custom frames, the team at Atelier Luma created the first series of salt panels that were grown locally through a farm-like system, utilizing the natural crystallization process in the salt fields.
Henna Burney and Karlijn Sibbel developed a technique of growing the salt crystals on a metal mesh submerged in the salins. They conducted extensive research to understand how factors such as wind, rain, temperature, water flow, and humidity would affect the crystallization process.
Transforming salt into a material of architectural scale:
To create the salt panels, the team at Atelier Luma had to control the crystallization process and shape it into a manageable geometric form, in this case, a perfect square. By transforming a naturally abundant material into one suitable for architectural use, they were able to produce more than 4000 unique panels, which were then used as a glass-like cladding system for Frank Gehry's tower at Luma Arles. Covering an area of 560 square meters, the "Wall of Salt" project is the first large-scale application of salt as a cladding material.
According to Henna, salt was chosen for the project "because it's a naturally non-flammable material, which is a requirement when using natural materials in that area." Additionally, the crystallization process is carbon-neutral, making the panels highly eco-friendly. "The production using solar energy (crystallization) doesn't have any negative impact on the environment."
The panels can also be removed and replaced if necessary, and if damaged, they can be recrystallized and restored by placing them back into the water of the Crystallization Plant. Through careful research and following specific constraints, the salt panels have proven to be an innovative solution that reduces heat loads, resists fire, adds a unique aesthetic touch, and contributes to sustainability.
Although there are many obstacles to overcome in order to envision a future where natural resources such as salt can replace traditional materials, it is clear that "the future will be built with materials that are both new and old." By combining research, new technologies, and innovation, salt has the potential to become one of these new materials. To truly enhance sustainability and resource efficiency in the years to come, it is essential to draw inspiration from nature, support local production, and, most importantly, think creatively.