Energy Harvesting from Temperature Fluctuations using High Thermal Effusivity Materials

Technology

Transient energy harvesting devices, also known as thermal resonators, have been developed as a significant improvement over prior art. These devices consist of two thermal components separated by an energy conversion device. By employing thermal diodes as thermal components and either a heat engine or thermoelectric as the energy conversion device, this technology achieves enhanced efficiency. With the thermal components exposed to ambient temperature fluctuations, the energy conversion device uses the temperature difference between the two thermal components to harvest energy. The thermal components can be tuned to perform optimally at a specific target frequency of temperature oscillations, eliminating the dependence on high-frequency conditions. The thermal resonators have monitors that communicate and process data from the environment and thermal components to achieve tuning. This advancement allows the devices to utilize a vast range and variety of ambient temperature fluctuations. Additionally, the integration of materials with ultra-high thermal effusivities and the ability to fine-tune the thermal components optimizes power generation. The adaptability and tunability of this technology make it easily integrated into existing structures such as buildings, cars, or benches, making thermal resonators a promising next step for clean power generation.  

Problem Addressed 

Current thermal energy harvesting methods can be classified into two categories: static or transient, each of which present notable drawbacks. Static energy harvesting, exemplified by solar energy, makes use of persistent renewable sources. However, the high conductivity of the materials used in static devices decreases the efficiency of energy conversion. Meanwhile, transient energy harvesting uses temperature fluctuations to convert energy. Harvesting energy using high-frequency temperature variations is considerably more efficient, but these conditions are less persistent in the environment. This technology proposes novel methods for optimizing power generation by leveraging thermal effusivity to address the limitations of existing approaches.  

Advantages

• More efficient and clean energy source. 

• Helps to reduce over-reliance on fossil fuels. 

• Overcomes a significant obstacle in transient energy harvesting: the scarceness of high-frequency temperature oscillations in the environment. 

• Thermal resonators can be conveniently placed on preexisting objects (buildings, cars, benches, etc.). 

• Tuning capabilities allow for energy harvesting at specific target frequencies of temperature oscillations. 

Publications

Cottrill, L., et al. "Ultra-high thermal effusivity materials for resonant ambient thermal energy harvesting." Nature Communications 9 (2018).

Bakytbekov, A., et al. "Multi-source ambient energy harvester based on RF and thermal energy: Design, testing, and IoT application." Energy Science & Engineering 8, no. 11 (2020): 3883-3897.

Bakytbekov, A., et al. "Synergistic multi-source ambient RF and thermal energy harvester for green IoT applications." Energy Reports 9 (2023): 1875-1885.

Cottrill, L., et al. "Persistent energy harvesting in the harsh desert environment using a thermal resonance device: Design, testing, and analysis." Applied Energy 235 (2019): 1514–1523.

Zhang, G., et al. "Persistent, single-polarity energy harvesting from ambient thermal fluctuations using a thermal resonance device with thermal diodes." Applied Energy 280 (2020): 115881.

Zhang, G., et al. "High Thermal Effusivity Nanocarbon Materials for Resonant Thermal Energy Harvesting." Small 17, no. 48 (2021): 2006752.