US Scientists, Samsung Team Hit 100% Cooling Efficiency With

Refrigerators and air conditioners have become necessities in modern life, but the technology driving them hasn’t changed much in decades until now. In a groundbreaking collaboration, Samsung and researchers at the Johns Hopkins Applied Physics Laboratory (APL) are turning the page on traditional cooling methods by developing solid-state, thermoelectric-based refrigeration that could render compressor-based systems obsolete.

Globally, most cooling systems rely on compressor-based refrigeration, where heat is absorbed and expelled by circulating chemical refrigerants through coils. While effective, this method is bulky, energy-hungry, and often harmful to the environment due to the use of greenhouse gases. With rising global temperatures and an ever-increasing demand for cooling, there is a pressing need for a sustainable alternative.

This is where thermoelectric cooling steps in. Instead of relying on compressors and harmful chemicals, thermoelectric coolers move heat using electrons traveling through specially designed semiconductor materials. The result is a system with no moving parts, no refrigerants, and a potential for miniaturization and scalability.

Until recently, thermoelectric cooling faced limitations—it lacked the efficiency needed to compete with traditional systems. That changed with the introduction of CHESS (Controlled Hierarchically Engineered Superlattice Structures), a breakthrough in nanoengineering developed by APL researchers.

Initially designed for national security applications and noninvasive medical cooling, the CHESS thin-film technology is now being reimagined in partnership with Samsung for large-scale refrigeration.

“It marks a significant leap in cooling technology,” said Rama Venkatasubramanian, chief technologist for thermoelectrics at APL. “It sets the stage for translating advances in thermoelectric materials into practical, large-scale, energy-efficient refrigeration applications.”

In rigorous testing, the CHESS-enhanced modules demonstrated double the efficiency of traditional bulk thermoelectric materials at room temperature. Compared to current compressor systems, they are 75% more efficient at the module level and 70% more efficient in a fully integrated refrigeration system.

One of the most impressive aspects is the minimal material requirement. A single cooling unit was made using just 0.003 cubic centimeters of material, roughly the size of a grain of sand, making it highly cost-effective and scalable.

And how did the team manufacture such intricate nano-materials? Interestingly, they turned to a tried-and-true technique used in solar and LED industries—metal-organic chemical vapor deposition (MOCVD).

“We used MOCVD to produce the CHESS materials,” said Jon Pierce, senior research engineer at APL.
“[It’s] scalable, cost-effective, and capable of large-volume manufacturing.”

Looking ahead, the researchers believe this thin-film thermoelectric technology could scale up just like lithium-ion batteries did—from tiny consumer electronics to large-scale infrastructure like building HVAC systems.

“This thin-film technology… could grow to support large building HVAC applications,” Venkatasubramanian noted.