APL’s CHESS Thin Films Nearly Double Refrigeration Efficiency

APL’s CHESS thin films nearly double refrigeration efficiency. The scalable materials could transform cooling and energy-harvesting technologies.

Scientists at the Johns Hopkins Applied physics Laboratory (APL) in Laurel, Maryland, have created a new solid-state thermoelectric refrigeration system that is simple to manufacture and twice as efficient as devices built with standard bulk thermoelectric materials. As the global need for compact, reliable, and energy-efficient cooling technologies continues to rise, this development provides a promising alternative to conventional compressor-based refrigeration.

In a study published in Nature Communications, researchers from APL, working with refrigeration engineers at Samsung Research, demonstrated notable improvements in heat-pumping efficiency and cooling capacity. These gains were made possible thru high-performance nano-engineered thermoelectric materials developed at APL, known as controlled hierarchically engineered superlattice structures (CHESS).

The CHESS platform represents the culmination of a decade of APL research on advanced nano-engineered thermoelectrics and their applications. Originally designed for national security purposes, the material has since been adapted for othre uses, including noninvasive cooling therapies for prosthetics, and was recognized with an R&D 100 award in 2023.

New Material Dramatically Boosts Thermoelectric Cooling Efficiency

Researchers have achieved a significant breakthrough in thermoelectric cooling technology, potentially paving the way for more energy-efficient refrigerators and air conditioners. A team at the Applied Physics Laboratory (APL) developed a new material, dubbed CHESS (Compositionally Heterostructured Energetic and Structural Solids), that dramatically improves cooling efficiency compared to conventional materials.

To test the new material, researchers compared refrigeration modules using traditional bulk thermoelectric materials with those using CHESS thin-film materials in standardized refrigeration tests. They measured and compared the electrical power needed to achieve various cooling levels in the same commercial refrigerator test systems. Samsung Research’s Life Solution Team, led by executive vice president Joonhyun Lee, collaborated with APL to validate the results through detailed thermal modeling. This modeling quantified heat loads and thermal resistance parameters, ensuring accurate performance evaluation under real-world conditions.

The results were striking.Using CHESS materials,the APL team achieved nearly 100% improvement in efficiency over traditional thermoelectric materials at room temperature (around 80 degrees Fahrenheit,or 25 C). They then translated these material-level gains into a near 75% improvement in efficiency at the device level in thermoelectric modules built with CHESS materials, and a 70% improvement in efficiency in a fully integrated refrigeration system. Each improvement represents a significant leap over state-of-the-art bulk thermoelectric devices. These tests were completed under conditions that involved significant amounts of heat pumping to replicate practical operation.

built to Scale

Beyond improving efficiency,the CHESS thin-film technology uses remarkably less material-just 0.003 cubic centimeters, or about the size of a grain of sand, per refrigeration unit.This reduction in material means APL’s thermoelectric materials could be mass-produced using semiconductor chip production tools, driving cost efficiency and enabling widespread market adoption.

“This thin-film technology has the potential to grow from powering small-scale refrigeration systems to supporting large building HVAC applications, similar to the way that l