Mechanical engineers at Georgia Tech have combined two commonly found salts to create an efficient thermal energy storage system. This innovation could significantly reduce buildings’ reliance on fossil fuels and aid in the battle against climate change.
As the world faces the twin challenges of climate change and increasing energy consumption, researchers at Georgia Tech’s George W. Woodruff School of Mechanical Engineering are developing groundbreaking thermal energy storage solutions using common salts. This innovative approach could help reduce our dependence on fossil fuels and pave the way for a more sustainable future.
Storing Heat for a Greener Tomorrow
In the quest for efficient heating systems that do not rely on traditional, polluting fuels, Georgia Tech researchers have demonstrated that combining two commonly found salts can effectively store clean energy as heat.
This stored heat can then be utilized for warming buildings or even integrated with heat pumps to provide cooling.
The study, published in the Journal of Energy Storage under the title “Thermochemical Energy Storage Using Salt Mixtures With Improved Hydration Kinetics and Cycling Stability,” showed promising potential for the salts in question.
The Science Behind Salt-Based Energy Storage
The mechanics of heat storage employed by the researchers hinge on a simple reversible chemical reaction. The forward reaction absorbs and stores heat, while the reverse reaction releases it, making the stored heat available for use in a building.
Assistant Professor Akanksha Menon, a key figure in this research, began her journey into thermal energy storage during her doctoral studies. Upon joining Georgia Tech and establishing the Water-Energy Research Lab (WERL), Menon delved deeper into both the technology and materials for energy storage, striving to integrate them into building systems.
“I realized there are so many things that we don’t understand, at a scientific level, about how these thermo-chemical materials work between the forward and reverse reactions,” she said in a news release.
Innovative Combination of Salts
Menon’s team discovered that different salts, when combined, could complement each other’s strengths and weaknesses.
They determined that magnesium chloride and strontium chloride serve as an effective pair. Magnesium chloride’s tendency to overhydrate was balanced by strontium chloride’s slow hydration process.
“We didn’t plan to mix salts; it was just one of the experiments we tried,” Menon added. “Then we saw this interactive behavior and spent a whole year trying to understand why this was happening and if it was something we could generalize to use for thermal energy storage.”
Future Directions and Broader Impact
Supported by a National Science Foundation CAREER Award and a U.S. Department of Energy’s Energy Earthshots project, Menon and her team are exploring various applications for these salt-based systems.
One promising concept involves filling drums with salts in a packed bed reactor, where hot air dehydrates the salts to store energy and humid air rehydrates them to release the stored heat.
“Our research spans the range from fundamental science to applied engineering thanks to funding from the NSF and DOE,” Menon added. “This positions Georgia Tech to make a significant impact toward decarbonizing heat and enabling a renewable future.”
With the potential to utilize widely available and cost-effective materials such as salt, this research could lead to climate-friendly energy solutions, helping buildings reduce their carbon footprints and contribute to the fight against climate change.