A research team led by Arun Majumdar, Kan-Zhi Fung, and colleagues from Johns Hopkins University Applied Physics Laboratory (JHU-APL) in the United States and Samsung Electronics in South Korea has developed a new solid-state refrigeration system based on nano-engineered thin-film thermoelectric materials. The study demonstrates the viability of this technology as an alternative to traditional vapor-compression cooling, with significant improvements in performance and energy efficiency.
The project was driven by the growing global need for compact and efficient refrigeration solutions that avoid harmful chemical refrigerants such as HFCs. Researchers used metal-organic chemical vapor deposition (MOCVD) to fabricate thermoelectric modules based on CHESS (Controlled Hierarchically Engineered Superlattice Structures), achieving much higher figures of merit (ZT) than bulk thermoelectric materials. At room temperature (300 K), individual P-N couples reached ZT values of up to 1.24—around 65% higher than typical bulk devices.
System-level tests showed a 77-couple thin-film thermoelectric cooling (TFTEC) module achieved a ZT of 1.05, a 70% improvement over a standard 241-couple bulk module. In low heat load conditions, a 16-couple module delivered a coefficient of performance (CoP) of approximately 15 for a 1.3 °C temperature differential, using only 80 mW of power to move 1.2 W of heat. The high CoP at small temperature gradients supports use in distributed and portable refrigeration.
The devices rely on thin-film structures (~25 µm thick), enabling much greater cooling power density compared to bulk systems. Scalable designs ranging from 16 to 80 couples were fabricated using automated assembly techniques from the semiconductor industry. The modular approach allows flexible integration into different cooling systems.
Samsung Electronics contributed system modeling and testing using commercially available refrigerators. The TFTEC modules were embedded directly into the refrigeration system, and performance was assessed under operational conditions. Researchers also demonstrated the durability of the modules in vibration and shock tests, suggesting potential for applications from consumer appliances to aerospace.
“Realization of high ZT and high-performance devices using sputtering and solution-based techniques to create nano-engineered thin-film thermoelectric materials are future possibilities for large volume refrigeration applications,” the authors noted in the study.
The findings underscore the potential for solid-state thermoelectric refrigeration to replace or complement mechanical systems, particularly in compact or distributed applications where reliability, low material usage, and precise thermal control are critical.