Thermoelectric cyclic-thermal regulation: A new operational mode of thermoelectric materials with high energy efficiency

Context & scaleThermal energy has been a vital energy source throughout the progress of human civilization. Heat transfer preserves our body temperature and enables the creation of farming tools, which lead to the Agricultural Age. Heat transformation was the driving force behind machinery during the Industrial Age. Thermoelectric materials can realize the direct conversion between heat and electricity, achieving the dual purpose of heat transfer and energy transformation. A novel and more efficient heat-transfer system, which utilizes a cyclical heat-pumping arrangement between two vessels, has a rapid thermal response and a wide range of potential uses. This innovative system can save electricity consumption by 42% and increase the cycle speed by 2.3 times relative to traditional systems, indicating extremely promising applications for gas separation, temperature-driven actuators, and others.Highlights•A new operational mode, thermoelectric cyclic-thermal regulation, is first proposed•Its actual algebraic model is derived based on the finite difference method•It is employed in the gas-separation system, featuring remarkable energy efficiency•An empirical figure of merit is proposed to guide material optimization in this modeSummaryThe thermoelectric cyclic-thermal-regulation (TEcR) system was defined as cyclical heat pumping between two vessels in a transient mode, which has emerged as a new application in gas separation and temperature-driven soft robots. Here, we provided systematic theoretical fundamentals relative to the TEcR system and proposed the determining factors and performance scales. We have also designed and fabricated a thermoelectric CO2-gas-separation system based on low-temperature adsorption and high-temperature desorption, verifying the feasibility of the TEcR system. Our experiments unequivocally demonstrate the significant potential of the TEcR system, with energy consumption savings of 42% and cycle frequency improvements of 2.5 times compared with electrical heater systems. We also proposed an empirical figure of merit to guide the thermoelectric material optimization strategies for the TEcR application. Our work sheds light on the new application of thermoelectric materials, which would generate implications for a wide range of industrial applications that use multi-plate thermal energy.