Anton L. Cottrill, Albert Tianxiang Liu, Yuichiro Kunai, Volodymyr B. Koman, Amir Kaplan, Sayalee G. Mahajan, Pingwei Liu, Aubrey R. Toland, Michael S. Strano.
Ultra-high thermal effusivity materials for resonant ambient thermal energy harvesting.
Nature Communications, 2018; 9 (1)
> Materials science has made progress in maximizing or minimizing the thermal conductivity of materials; however, the thermal effusivity—related to the product of conductivity and capacity—has received limited attention, despite its importance in the coupling of thermal energy to the environment. Herein, we design materials that maximize the thermal effusivity by impregnating copper and nickel foams with conformal, chemical-vapor-deposited graphene and octadecane as a phase change material. These materials are ideal for ambient energy harvesting in the form of what we call thermal resonators to generate persistent electrical power from thermal fluctuations over large ranges of frequencies. Theory and experiment demonstrate that the harvestable power for these devices is proportional to the thermal effusivity of the dominant thermal mass. To illustrate, we measure persistent energy harvesting from diurnal frequencies, extracting as high as 350 mV and 1.3 mW from approximately 10 °C diurnal temperature differences.
This isn't really as novel as they're making it sound.
The atmos clock which works on the same principle of temperature and pressure variation has been around for a few hundred years. They've just changed it to some modern solid state electronics.
It just doesn't generate enough power to warrant anything.
I suspect the research that goes into utilizing ambient radio waves for energy will fill virtually any niche this does, but better.