Dynamic pyroelectric energy harvesting from lithium tantalum oxide (LiTaO3

Pyroelectric effect is one of the phenomena that can convert wasted thermal energy into useful electric energy. Using dynamic method a pyroelectric material can harvest heat radiation from surrounding environment as an input into necessary circuits that needs resources. To improve this conversion efficiency, an AC/DC converter between a pyroelectric harvester and the load needs to be implemented. In this experiment, direct current (d.c.) on the order of 10-9A and voltage (d.c.) on the order of 10-1V are measured for a given 10 M⊕ load, by providing cyclic temperature fluctuations of around 0.4K/s on a single crystal lithium tantalum (LiTaO3). Analysis and experimental research were conducted over a range of resistive load and chopping frequencies in order to optimize the energy harvesting process. The range thus identified was used for optimization of the converter. The generated pyroelectric current is converted from a.c. to d.c. and rectified by a voltage doubler. Later, the pyroelectric energy was stored in a 100muF load capacitor. It was observed that lower frequency provides larger energy storage capability for capacitors although frequency range for generating maximum power from the pyro-electric material might be different. In this experiment, chopping frequency range between 2Hz-6Hz is optimum for highest power generation from LiTaO3 material with an area of 0.001964 m2.