Thermomechanical Cycle for Thermal and/or Mechanical Energy Conversion Using Ferroelectric Materials
BACKGROUND
Rising awareness in sustainable and efficient energy technologies has stimulated efforts in harvesting energy that would otherwise be wasted. The Olsen cycle, performed on pyroelectric materials, utilizes time-dependent temperature oscillations to convert thermal energy directly into electricity. And although it produces large energy densities, the Olsen cycle requires that source material be hotter than its Curie temperature to generate energy. Moreover, its power density is limited by slow thermal relaxation processes.
INNOVATION
UCLA researchers in the Department of Mechanical Engineering have developed a new technology that takes thermal and/or mechanical energy, and converts it directly into electrical energy. This new thermomechanical cycle can harvest what is typically waste heat from internal combustion engines, heat pumps and refrigeration systems. Potential mechanical energy sources include vibrations from roads and various transportation systems. This system improves upon the Olsen cycle in several ways. It can generate energy at lower temperatures, the maximum power output is greater, and the new cycle can yield efficiencies higher than the Olsen cycle.
APPLICATIONS
Harvest waste heat energy and convert it to usable electricity.
- Solar radiation
- Power cycles (e.g., gas turbines, combustion engines)
- Refrigeration cycles (e.g., refrigerators, AC units)
- Heat pumps
Harvest mechanical energy and convert it to usable electricity
- Vibrations from transportation systems and various mechanical systems
- Waste mechanical energy from moving objects (e.g., cars, trains, elevators, cranes)
ADVANTAGES
By combining heating and mechanical work, this new cycle can:
- Directly generate electricity, even at low temperatures
- Achieve greater maximum power output than the Olsen cycle while maintaining high energy density
- Achieve high energy conversion efficiencies
STATE OF DEVELOPMENT
These new cycles have been reduced to practice on pyroelectric single crystals in Professor Pilon’s laboratory.