Scientists have created a new material derived from seaweed that can store heat for reuse. The material, which is made from alginate, a natural polymer extracted from brown algae, could have applications in heating, cooling and energy storage.
The researchers from the University of Birmingham in the UK and Huazhong University of Science and Technology in China found that alginate can retain up to 85% of its stored heat after 24 hours and can release it on demand by applying a small voltage or a change in pH.
The material works by exploiting the reversible gelation of alginate. When alginate is dissolved in water, it forms a viscous solution that can trap water molecules. When the solution is dried or cooled, it forms a gel that can hold a large amount of latent heat. This heat can be released when the gel is rehydrated or heated.
The researchers say that the material is biodegradable, low-cost and abundant, making it an attractive alternative to conventional phase change materials (PCMs) that are often derived from petroleum or metals. PCMs are substances that can store and release large amounts of heat by changing their physical state, such as melting and solidifying.
“Alginate is a very cheap and widely available material that has been used for decades in food, biotechnology and medicine,” said Dr. Xuewu Xu, a lecturer in chemical engineering at the University of Birmingham and one of the lead authors of the study. “We have shown that it can also be used for thermal energy storage with high efficiency and controllability.”
The researchers envision that the alginate-based material could be used in various ways, such as coating building materials to regulate indoor temperatures, creating smart textiles that can warm or cool the wearer, or designing compact devices that can store renewable energy for later use.
“This is a very exciting discovery that could lead to significant environmental and economic benefits,” said Professor Yulong Ding, director of the Birmingham Centre for Energy Storage and another lead author of the study. “We hope that our work will inspire more research on seaweed-based materials and their applications in the fields of energy and environment.”