Pyroelectric Power Research Articles

Interlaboratory Comparison of Power Measurements at Millimetre- and Sub-Millimetre-Wave Frequencies

The aim of this paper is to compare the power measurement capabilities in millimetre- and sub-millimetre-wave frequency bands of several national metrology institutes and one research institute. The first comparison, in WR-6.5 waveguide (110 GHz to 170 GHz), involved NPL, TUBITAK UME and PTB. The second comparison, in WR-1.5 waveguide (500 GHz to 750 GHz), involved NPL, METAS, TUBITAK UME, LNE, WAT, GUM and VDI. Two types of travelling standards were used for these comparisons: a thermoelectric power sensor in the WR-6.5 band and a calorimetric power sensor in the WR-6.5 and WR-1.5 bands. The thermoelectric power sensor was characterised by the participants against their own standards and a generalised effective efficiency was calculated. The calorimetric power sensor operating in the WR-6.5 band was measured to observe its behaviour during the comparison and was also measured in the WR-1.5 band after being fitted with a suitable waveguide taper and used in conjunction with a frequency multiplier. The participants measured the output of the calorimetric power sensor and their own power sensor standard. A normalised power ratio method was used as a comparison parameter for the WR-1.5 band measurements. In addition, a pyroelectric power standard was used by METAS to measure absolute power, and a frequency of 650 GHz was used as a link between the absolute power and the power ratios. Finally, all but two of the measurement points compared between the participants achieved agreement in terms of En scores less than 1. For the first time, an interlaboratory comparison of power measurements at sub-millimetre frequencies has been performed and, overall, good agreement was achieved between the different laboratories.

Exploiting the Potential of Pyroelectric–Piezoelectric Hybrid Devices for Low‐Grade Thermal Energy Harvesting

This study proposes a separate and combined (pyroelectric + piezoelectric) energy harvesting system using a bimetallic beam. Hybrid energy harvesting is achieved by waste thermal energy using thermal expansion mismatch of the bimetallic beam. In this regard, four types of design are proposed, along with various heating/cooling cycles. Auxetic layers in a bimetallic beam are used to enhance the power. The best‐performing design and heating/cooling cycle are considered for further power increment. Two models are simulated based on low (model C3) and high heat consumption (model C5). The load resistance, frequency, bimetallic beam and pyroelectric/piezoelectric layer thickness are varied and maximum power is obtained at 175 MΩ (C3), 75 MΩ (C5), 0.02 Hz (C3 and C5) and 0.4 mm (C3 and C5) as 20 μW (C3) and 40 μW(C5), respectively. The piezoelectric, pyroelectric and combined power variation is the effect of stress and temperature fluctuations on H‐PEH layer. Additionally, five well‐known higher pyroelectric/piezoelectric coefficient materials are studied and found that La‐NBT‐BT‐Ta gives the maximum power of 0.811 and 1.99 mW for combined (pyroelectric + piezoelectric) effect in low (C3) and high (C5) heat consumption model, respectively. The stress generated in both models is analyzed to look at practical feasibility.

Enhancement of a pyroelectric body energy harvesting scheme employing pulsed electric fields.

This research utilizes waste heat energy as a sustainable energy source to enhance pyroelectric power output by combining pyroelectric nanogenerators with an external pulsed electric field. When the surface temperature of the pyroelectric body varies, applying different pulses of the external electric field results in maximum power accumulation. A novel power-generating experimental setup was developed to measure and compute pyroelectric power generation. A standard Fuji ceramic C-9 sample was used to generate pyroelectric energy in a 20 °C temperature range from 120 to 140 °C. The continuous temperature variation frequency was 0.05Hz, and the pulsed electric field was applied when the temperature rose. Pulses of the electric field with widths of 10, 50, 100, and 200ms were applied to the sample under different pulse amplitudes, and the amplitude of each pulse was 250, 500, 1000, or 1500 V/mm. The maximum power generated through the application of an external pulsed electric field under the above-mentioned conditions was evaluated. This system had the highest power density of 0.204 mJ cm-2 °C-1kV-1. In addition, for the lowest input power, the maximum power generation condition was a 10ms pulse width and an amplitude of 250Vmm-1 in the applied electric field. This state might power smart sensor modules, IoT devices, automobiles, and other waste heat energy applications. Nano-pulse electric field applications may reduce input power to its lowest level, dependent on net-producing power. Therefore, new researchers can use net-generation power efficiency to create a large-scale power source using multiple pyroelectric arrays.

Improvement of Power Recovery by Applying a Multi-Pulse Electric Field in the Thermoelectric Cycle Power Generation Process with Pyroelectric Materials

Nanogenerator energy harvesting technologies that transform thermal energies into electricity may help address the growing need for green power. Therefore, this research aims to increase power generation by combining waste heat with pyroelectric nanogenerators as a sustainable energy source. Under optimal conditions, an external multi-pulse electric field can be utilized to generate power using thermoelectric cycle power generation. The greatest power may be gathered by applying various pulses of the external electric field at temperature changes on the surface of the pyroelectric materials. To generate pyroelectric power, a C9 BZT sample was used, and the lowest temperature difference for accomplishing this was 20 °C, with all measurements made on a sample with a lower limit of 120 °C. The maximum generation density was 0.104 mJ/cm2°CkV for a pulse width of 10 ms and 20 pulses of a low voltage (250 V/mm) input electric field. A multi-pulse electric field with low input voltage increases the power generation performance ratio (η) with the pulse count. At the largest number of pulses, the greatest η value for 250 V/mm was 7.834. Finally, it was determined that the developed pyroelectric power generation system may be more effective if a low-voltage, multi-pulse electric field is used.

Phase transition enhanced pyroelectric nanogenerators for self-powered temperature sensors

Pyroelectric materials are of interest for waste heat utilization and thermal detection. However, the low output current and inefficiency reduces their effectiveness. Here, we utilize the abrupt decrease in polarization of ferroelectric BaTiO3 materials around Curie temperature to improve the output performance of a pyroelectric nanogenerator. The variation of the polarization leads to a large change in the density of surface free charges, resulting in an increase of pyroelectric current. We have designed a temperature control and recording system to realize direct measurement of the pyroelectric output current. The pyroelectric current, power and energy conversion efficiency of the device near the Curie temperature were measured to be 15.6-fold, 18-fold and 15.8-fold higher than those acquired near room temperature. Moreover, the temperature induced current and charge density enhancement can be applied to detect temperature and temperature change. The responsivity of the self-powered temperature sensor near Tc is 120 nC/cm2∙K, which 4.8 times higher than that near room temperature (25.1 nC/cm2∙K). The results confirmed the ability to exploit a ferroelectric phase transition for pyroelectric performance enhancement.

Operando structure observation of pyroelectric ceramics during power generation cycle

The microscopic origin of the pyroelectric power generation using ferroelectric ceramics for energy harvesting from time-varying waste heat can be understood by conducting operando neutron diffraction measurements. The behavior of the domain orientation and lattice strain in the lead zirconate titanate-based ceramics with a tetragonal structure during the novel power generation cycle combining the electric field and the temperature change were investigated. The [001] domains and the lattice strain of the (111) plane in the direction parallel to the electric field increase in the process of simultaneous rise in the electric field and temperature and rapidly decrease in the process of the field drop. Furthermore, larger structural changes were found in the material and cycle condition, giving higher power density. The alignment of the domain orientation by the electric field and its randomization by the higher temperature during the cycle are critical features of the current power generation system.

Examination of pyroelectric power generation over a wide temperature range by controlling the Zr:Sn composition ratio of PLZST

ABSTRACT Several studies have been conducted on energy harvesting, which involves conversion of unused environmental energy into a power source. More than half of the energy consumed is wasted as heat. Therefore, attempts are being made to increase energy efficiency by effectively utilizing the waste heat as renewable energy. In this study, we focused on the time-varying waste heat source and fabricated lead lanthanum stannate zirconate titanate (PLZST) ceramics, which are pyroelectric materials. The electrical properties and power densities of the PLZSTs with five different compositional ratios of Zr and Sn were evaluated as functions of temperature. As the proportion of Zr increased, both the maximum dielectric constant and the maximum power density at each composition ratio shifted to higher temperatures. By controlling the Zr:Sn ratio in PLZSTs, power densities of more than 8 mW/cm3 were obtained over a wide temperature range of 140–200°C. In addition, power densities of more than 10 mW/cm3 were obtained between 150°C and 180°C. Therefore, we observed that PLZST is a promising material for the recovery of power from low-grade heat sources below 200°C.

Pyroelectric power generation in PLZST material by temperature dependent phase transformation

Efforts are being made to increase the efficiency of energy consumption by effectively using the dissipated heat as a source of renewable energy. Herein, we focused on a heat source wherein the temperature varies with time and recovers electrical energy from thermal energy by the pyroelectric effect. Further, we evaluated the net power density of the (Pb, La) (Zr, Sn, Ti)O3 material that is produced by its phase transformation as a result of increase in temperature. It was measured by the Sawyer-Tower circuit that was installed a diode and switch. The results showed that when the low or high temperature side of the measurement environment is in the antiferroelectric phase, the net power density decreased or became negative. Additionally, we estimated the range of temperature wherein a high-power density could be attained by examining the changes in it due to phase transformation.

Frequency regime dependent figures of merit and optimization guidelines for maximizing pyroelectric power output

Traditionally, pyroelectric energy conversion research has focused on improving energy output per cycle between fixed temperature bounds; however, most end-uses have fixed power, not energy, demands. Here, we analyze pyroelectric energy harvesting systems through the lens of maximizing power output, focusing specifically on the oft-overlooked details of the average temperature amplitude of the pyroelectric material which can be far smaller than the temperature amplitude of the available thermal resource. We describe this average temperature amplitude as a function of thermophysical properties, geometry, and other system variables for two different types of thermal energy sources. Ultimately, we identify figures of merit (FOMs) for locally improving the power harvesting performance within each of three distinct frequency regimes, as well as provide guidance for maximizing the power harvesting performance under certain constraints. This combination of FOMs and maximization guidance will aid in the future design and optimization of pyroelectric energy harvesting systems.

Predicting performance of thermal-electrical cycles in pyroelectric power generation

A method is proposed to predict the power generation performance of a pyroelectric generator (PEG) for waste-heat recovery systems in which an external electric field is applied to a ferroelectric material in synchrony with rapid temperature changes. The net generated energy density ND of the PEG at any temperature and electric field is predicted for two thermal-electrical cycles (including the Olsen cycle). This is done by approximating the dependence of the polarization density on temperature and electric field using hysteresis loop measurements. The difference between the predicted and measured values of ND was less than 15%. This method could be used to screen promising candidate materials for PEGs.

Pyroelectric power generation from the waste heat of automotive exhaust gas

A waste heat recovery system is investigated basically. Original electro-thermodynamic cycle and novel system are expected to be viable in any heat sources with time dependent temperature changes instead of the spatial temperature gradient.

Temperature stability of PIN-PMN-PT ternary ceramics during pyroelectric power generation

This study addresses pyroelectric power generation through an original electrothermodynamic cycle for environmentally friendly automotive applications. Relaxor-based ternary Pb(In1/2Nb1/2)O3-Pb(Mb1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) ceramics near a morphotropic phase boundary were applied as pyroelectric materials, and their electrical properties were investigated at different temperatures. Structural disordering, depending on the PIN content, influenced the diffuse phase transition between the tetragonal and cubic structures and contributed to the power-generating behavior. The net power-generating energies (Pnet) were 2.43–3.01 mW/cm3 at temperatures above 200 °C and were maintained at above 1 mW/cm3 over a temperature range of approximately 100 °C. In the PIN-PMN-PT system, the temperature dependence of the power-generating performance was improved, and disordering of the perovskite crystal structure can be controlled to achieve pyroelectric energy conversion by the electrothermodynamic cycle over a wider range of usage temperatures.

Possible Applications of Nanomaterials for Nuclear Fusion Devices

Abstract Conditions of nuclear fusion and nuclear fusion devices were described, and some possible applications of nanomaterials for nuclear fusion devices were presented in the present article. Muon-catalyzed fusion is one of methods for nuclear fusion to cause even at room temperature or lower, and protons or heavy ions with huge energy are irradiated to metals such as beryllium or copper, which results in emission of negative or positive charged muons from the metals. An experiment using a pyroelectric power source using lithium tantalite crystal was also reported to achieve nuclear fusion in a desktop-like device. Hydrogen storage is also important for the fusion devices, and the possibility of hydrogen storage in hydrogen storage metallic alloys was studied by diffusion calculation and potential calculation of deuterium fusion. Enhancement of deuterium diffusion in the Pd alloys would be one of the key points for energy materials. Carbon(C)/copper(Cu)-based composite materials with high thermal conductivity and good stability at high temperatures were also developed by adding a small amount of titanium, which has a low enthalpy of alloy formation with C and Cu. These carbon-based materials could be a candidate material for the plasma facing components of fusion devices.

Pyroelectric power generation with ferroelectrics (1-x)PMN-xPT

ABSTRACTA novel electrothermodynamic cycle based on temporal temperature variations (dT/dt); the pyroelectric effect was investigated for its potential role in the use of waste heat as renewable energy. Here, we present improved generating performance with relaxer ferroelectric ceramics ((1-x)Pb(Mg2/3Nb1/3)O3-xPbTiO3 (PMN-xPT)), which are well known for their strong dielectric and pyroelectric properties near the morphotropic phase boundary. The theoretical potential was evaluated using hysteresis loops, and the generating properties were analyzed in the laboratory using an engine dynamometer. The experiments yielded a value of 0.48 mW/cm3, which is 3 times larger than that obtained previously, because of the high polarization properties.

Pyroelectricity of Pb(Zr0.52Ti0.48)O3 films grown by sol–gel process on silicon

Pyroelectric Pb(Zr0.52Ti0.48)O3 films have been grown by sol–gel process on Si(001). Intrinsic pyroelectric coefficient has been measured through ferroelectric loops recorded at different temperatures and is about −300μC/m2K. Corresponding converted pyroelectric power density is estimated to be ~1mW/cm3 for a temperature variation of 10°C every 6s. Pyroelectric response of these films has been confirmed by direct measurements of the pyroelectric current with temperature variations at zero electric field. These results are of high interest for integrated thermally-sensitive devices.

Droplet generation for thermal transient stimulation of pyroelectric PZT element

This paper investigates a new way of thermal loading of pyroelectric element. Pyroelectric devices produce a current when submitted to a temperature change over time. In order to stimulate a pyroelectric device with fast thermal transients we used a stream of droplets from non-miscible fluids having different temperature created in situ by a T-junction microfluidic circuit. The succession of droplets flowing over the pyroelectric element creates temperature transients, heating up and cooling down steps that induce a pyroelectric current. This scheme has demonstrated the generation of AC signal from non-miscible fluids at two different temperatures without any synchronized pumping. The device is made of a stack of PZT and silver electrodes obtained by screen-printing on microscope glass blade. This patterning technique allows the deposition of a large number of devices on large surface substrates. It is a first step toward pyroelectric power generation harvesting energy from waste heat.

A 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3-based pyroelectric generator and temperature sensor

We report the extremely-high pyroelectric power generation of a relaxor ferroelectric 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-0.3PT) single crystal. The pyroelectric current and voltage of PMN-0.3PT depend on the electric poling voltage, the temperature-variation rate, and the measurement temperature. Near the structural transition temperatures of the rhombohedral-tetragonal transition (~380 K) and the tetragonal-cubic transition (~410 K), the temperature-induced change in the electric polarization results in a sharp enhancement of the pyroelectric power. Near the tetragonal-cubic transition temperature, i.e., the Curie temperature, we observe a pyroelectric current of ~100 nA and voltage of ~11 V. Near room temperature, we observe a pyroelectric current of ~1.4 nA and voltage of ~0.2 V from the touch of a human finger. These results imply that the relaxor ferroelectric PMN-0.3PT should be quite useful for pyroelectric energy-harvesting and temperature-sensing applications.

High pyroelectric power generation of 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 single crystal

We report the pyroelectric power generation of a relaxor ferroelectric 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) single crystal. For a temperature variation rate of 0.5 K/s, the PMN–PT generated a closed-circuit current of 10 nA and an open-circuit voltage of 1.1 V at room temperature. The pyroelectric current and voltage of the PMN–PT single crystal were proportional to the temperature variation rate and were sharply enhanced near the structural phase-transition temperature. Additionally, the PMN–PT pyroelectric generator produced stable power for excessive thermal cycling and was highly sensitive to random thermal fluctuations. Our results indicate the potential importance of PMN–PT for high-power pyroelectric generator applications.

Highly Stretchable Piezoelectric‐Pyroelectric Hybrid Nanogenerator

A highly stretchable hybrid nanogenerator has been developed using a micro-patterned piezoelectric polymer P(VDF-TrFE), PDMS-CNT composite, and graphene nanosheets. Mechanical and thermal energies are simultaneously harvested from a single cell of the device. The hybrid nanogenerator exhibits high robustness behavior even after 30% stretching and generates very stable piezoelectric and pyroelectric power outputs due to micro-pattern designing.

Improving Pyroelectric Energy Harvesting Using a Sandblast Etching Technique

Large amounts of low-grade heat are emitted by various industries and exhausted into the environment. This heat energy can be used as a free source for pyroelectric power generation. A three-dimensional pattern helps to improve the temperature variation rates in pyroelectric elements by means of lateral temperature gradients induced on the sidewalls of the responsive elements. A novel method using sandblast etching is successfully applied in fabricating the complex pattern of a vortex-like electrode. Both experiment and simulation show that the proposed design of the vortex-like electrode improved the electrical output of the pyroelectric cells and enhanced the efficiency of pyroelectric harvesting converters. A three-dimensional finite element model is generated by commercial software for solving the transient temperature fields and exploring the temperature variation rate in the PZT pyroelectric cells with various designs. The vortex-like type has a larger temperature variation rate than the fully covered type, by about 53.9%.The measured electrical output of the vortex-like electrode exhibits an obvious increase in the generated charge and the measured current, as compared to the fully covered electrode, by of about 47.1% and 53.1%, respectively.