Pyroelectric Harvesters for Generating Cyclic Energy

Abstract

Pyroelectric energy conversion is a novel energy process which directly transforms waste heat energy from cyclic heating into electricity via the pyroelectric effect. Application of a periodic temperature profile to pyroelectric cells is necessary to achieve temperature variation rates for generating an electrical output. The critical consideration in the periodic temperature profile is the frequency or work cycle which is related to the properties and dimensions of the air layer; radiation power and material properties, as well as the dimensions and structure of the pyroelectric cells. This article aims to optimize pyroelectric harvesters by matching all these requirements. The optimal induced charge per period increases about 157% and the efficient period band decreases about 77%, when the thickness of the PZT cell decreases from 200 μm to 50 μm, about a 75% reduction. Moreover, when using the thinner PZT cell for harvesting the pyroelectric energy it is not easy to focus on a narrow band with the efficient period. However, the optimal output voltage and stored energy per period decrease about 50% and 74%, respectively, because the electrical capacitance of the 50 μm thick pyroelectric cell is about four times greater than that of the 200 μm thick pyroelectric cell. In addition, an experiment is used to verify that the work cycle to be able to critically affect the efficiency of PZT pyroelectric harvesters. Periods in the range between 3.6 s and 12.2 s are useful for harvesting thermal cyclic energy by pyroelectricity. The optimal frequency or work cycle can be applied in the design of a rotating shutter in order to control the heated and unheated periods of the pyroelectric cells to further enhance the amount of stored energy.

Recent Advances in Pyroelectric Materials and Applications

“…There are many typical perovskite materials researched and applied, such as BaTiO 3 , [15,[52][53][54][55] BiFeO 3 , [14,[56][57][58] Pb(Ti, Zr)O 3 . [18,[59][60][61][62][63][64] By Reproduced with permission. [38] Copyright 2019, IOP Publishing Ltd. c) Variation of pyroelectric coefficient of Mn-(94.6NBT-5.4BT) crystals with different crystallographic orientations.…”

Energy Harvesting Technologies and Equivalent Electronic Structural Models—Review

“…A pyroelectric harvester [67][68][69][70][71][72] converts a temperature change into electric current or voltage. Piezoelectric effect is similar, but the ferroelectric behavior is different.…”

Wind-driven pyroelectric energy harvesting device

“…The effects of various factors including frequency of temperature change, capacitances, and resistances on stored energy were evaluated. A similar design was presented by Hsiao and Jhang [7] in which cyclic temperature fluctuations in a pyroelectric cell were induced via a motor-driven rotating disk with apertures that separate a PZT pyroelectric cell from a radiating heat lamp.…”