Air conditioners, refrigerators, and heat pumps help keep our homes, food, and electronics cool.
But the refrigerants they use can cause several problems.
These specialized fluids can leak into the environment, contribute to greenhouse gas emissions, and in some cases are flammable. Recovering and recycling used refrigerants is also difficult.
Scientists have long been searching for cleaner alternatives, and a team at the University of Notre Dame may have found a promising solution.
The researchers have developed a new cooling technology based on thermoelectric materials.
Their study, published in Materials Horizons, describes a low-cost way to manufacture these materials using a special ink and printing process.
Thermoelectric cooling works very differently from traditional air conditioning. Instead of using gases and compressors, thermoelectric devices move heat using electricity and solid materials.
They have no moving parts and require no refrigerant gases, which means there is no risk of leaks.
Professor Yanliang Zhang believes this technology could significantly improve the environmental impact of cooling systems.
One reason thermoelectric cooling has not become widespread is cost. Traditional methods of making thermoelectric devices can be expensive and difficult to scale up for mass production.
To overcome this challenge, Zhang and his team developed an ink-based manufacturing process that is both simple and affordable.
The process is surprisingly similar to printing images on T-shirts. The researchers created a special ink containing silver and selenium. The ink can be spread onto surfaces using techniques such as blade coating or screen printing, methods that are already widely used in industry.
After printing, the materials undergo additional processing and become thermoelectric components capable of moving heat.
During development, the team made an unexpected discovery. When silver and selenium powders were mixed together, they reacted very quickly to form a compound called silver selenide. This rapid reaction speeds up production and could lower manufacturing costs.
The researchers then carefully adjusted the proportions of silver and selenium to achieve the best possible cooling performance.
The printed materials performed remarkably well during testing. Their performance at room temperature was comparable to some of today’s leading thermoelectric materials.
Creating a complete thermoelectric cooling device requires two different types of materials, known as P-type and N-type semiconductors. The team’s earlier work focused on developing the P-type material. Their new silver-selenium ink provides the N-type component needed to complete the system.
The researchers are now working on combining these materials with metal electrodes to create fully functional cooling devices.
If successful, the technology could have many applications.
Compact thermoelectric coolers could help cool electronics, medical devices, automobiles, data centers, and even buildings. Because the systems are solid-state and contain no refrigerant gases, they could offer a cleaner and more sustainable alternative to today’s cooling technologies.
The researchers ultimately hope their printing method will make thermoelectric cooling affordable enough for widespread adoption. If that happens, future air conditioners and cooling systems may no longer depend on refrigerant gases at all, making cooling technology both greener and simpler.
