New Hybrid Energy Harvesting System Could Revolutionize Microdevices

Researchers have designed a hybrid energy harvesting system that generates power from magnetic fields and mechanical vibrations for low-power electronics.

“In nature, nothing is lost, nothing is created, everything is transformed,” this quote is attributed to chemist Antoine-Laurent de Lavoisier who discovered the law of mass conservation in the late 18th century.

If we refer to Einstein’s most famous equation (E = mc2), mass is basically energy at rest.

Lavoisier’s principle may be true for natural energy systems, but in the case of artificial energy generating devices, a great deal of energy gets wasted.

Today, no man-made system can reach a 100 percent thermal efficiency, or even get close.

For example, in conventional vehicles, only up to a 30 percent of the fuel energy goes to the primary function of making the engine run. Between 58 to 62 percent of the energy is lost as heat, and this is not a marginal loss.

Recuperating as much from lost power as we can could bring us a long way toward increasing the overall energy efficiency and reducing the carbon footprint of modern engines and machines.

Unlike conventional systems that require energy to generate energy, energy harvesters rely on ambient sources to run and provide power to other devices.

For example, piezoelectric devices harvest mechanical energy from ambient vibrations. Other devices capture the magnetic energy, but no system is currently capable of efficiently generating power from both sources at once.

Now, mechanical engineers at the Tsinghua University in Beijing, China, propose a new hybrid energy harvesting system that simultaneously targets the magnetic field and mechanical vibrations.

For this hybrid energy recovery scheme, the team managed to integrate a piezoelectric sheet onto a magnetostrictive substrate, leading to the system being able to harvest both forms of energy at once.

“We have proposed the idea of taking advantage of two different energy harvester approaches and showing their interactions. As we know, energy harvesters have been investigated for decades and many methods are involved. However, each approach has its shortcomings. It is difficult and interesting to break through the single energy harvester limitations. Moreover, revealing the interactive relationship is important for the work as a whole,” said Fulei Chu from Tsinghua University’s Department of Mechanical Engineering.

“We plan to conduct deeper research in the energy harvester field in the future. Wind energy, wave energy, and more smart material applications in energy systems will be the focus of our research besides the further investigations of this paper.”

In the future, such hybrid systems will allow devices with low-power needs, like wireless sensors, pacemakers, and wearables, to operate without a battery or any exterior battery source.