scholarly journals Giant electrocaloric materials energy efficiency in highly ordered lead scandium tantalate

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Youri Nouchokgwe ◽  
Pierre Lheritier ◽  
Chang-Hyo Hong ◽  
Alvar Torelló ◽  
Romain Faye ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Electric Field ◽  
Temperature Change ◽  
Adiabatic Temperature ◽  
Vapor Compression ◽  
Adiabatic Temperature Change ◽  
Direct Measurements ◽  
Cooling Devices ◽  
Efficient Alternative ◽  
Working Bodies

AbstractElectrocaloric materials are promising working bodies for caloric-based technologies, suggested as an efficient alternative to the vapor compression systems. However, their materials efficiency defined as the ratio of the exchangeable electrocaloric heat to the work needed to trigger this heat remains unknown. Here, we show by direct measurements of heat and electrical work that a highly ordered bulk lead scandium tantalate can exchange more than a hundred times more electrocaloric heat than the work needed to trigger it. Besides, our material exhibits a maximum adiabatic temperature change of 3.7 K at an electric field of 40 kV cm−1. These features are strong assets in favor of electrocaloric materials for future cooling devices.

Electrocaloric and electrostrictive effect of polar P(VDF–TrFE–CFE) terpolymers

2013 ◽  
Vol 03 (02) ◽  
pp. 1350015 ◽  
Author(s):  
Sheng-Guo Lu ◽  
Hui Xiong ◽  
Aixiang Wei ◽  
Xinyu Li ◽  
Qiming Zhang
Keyword(s):  
Electric Field ◽  
Temperature Change ◽  
Vinylidene Fluoride ◽  
Dielectric Material ◽  
Entropy Change ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Change ◽  
Poly Vinylidene Fluoride ◽  
Electrostrictive Effect ◽  
Rigid Ion Model

The electrocaloric effect (ECE) is the adiabatic temperature change or isothermal entropy change caused by the polarization change of a dielectric material when subjected to a change of external electric field. The electrostrictive effect is a form of elastic deformation of a dielectric induced by an electric field, associated with those components of strain which are independent of reversal field direction. It was found that both the ECE, e.g., adiabatic temperature change, and the electrostrictive strain in poly(vinylidene fluoride–trifluoroethylene–chlorofluoroethylene) (P(VDF–TrFE–CFE)) terpolymers are proportional to the square of the electric field. The adiabatic temperature change ΔT of ECE versus electric field can be illustrated using a modified Belov–Goryaga equation. ΔT is proportional to E2 when E is small. For electrostrictive effect, the rigid-ion model assumes that the anharmonic movement of the ions leads to the quadratic strain–electric field relation. The quotient of electrostrictive coefficient Q over the phenomenological coefficient β is empirically a constant, indicating that the larger the electrostrictive coefficient, the larger the ECE, which opens a new way to find out new electrocaloric materials.

The Electrocaloric Effect in BaTiO3 Thick Film Multilayer Structure at High Electric Field

2012 ◽  
Vol 512-515 ◽  
pp. 1304-1307 ◽  
Author(s):  
Yang Bai ◽  
Kai Ding ◽  
Guang Ping Zheng ◽  
San Qiang Shi ◽  
Lie Jie Qiao ◽  
...  
Keyword(s):  
Electric Field ◽  
Thick Film ◽  
Temperature Change ◽  
Multilayer Structure ◽  
Tape Casting ◽  
Adiabatic Temperature ◽  
Ferroelectric Ceramics ◽  
Heat Absorption ◽  
Electrocaloric Effect ◽  
Adiabatic Temperature Change

We demonstrated the superior electrocaloric effect (ECE) in BaTiO3 multilayer structure. The sample fabricated by tape-casting process has 120 effective ferroelectric layers with average layer thickness of 1.7 μm. The ferroelectric hysteresis loops were measured in the temperature range from 30 to 180 oC, and then the temperature dependences of ECE adiabatic temperature change and heat absorption were obtained according to Maxwell relation. A peak ECE adiabatic temperature change of 0.027 K/V and heat absorption of 0.36 J/g were observed near the ferroelectric phase transition at 125 oC under Vmax=25 V. The BaTiO3 thick film can sustain an external electric field (>500 kV/cm) several times higher than bulk ferroelectric ceramics (~30 kV/cm). Although the EC coefficient of BaTiO3 is much lower than lead-based ferroelectric ceramics, the ultrahigh working electric field endows it a large ECE, higher than that of most reported lead-based ferroelectric ceramics. In addition, the lead-free composition provides it a promising future in solid-state cooling technology.

Giant adiabatic temperature change in FeRh alloys evidenced by direct measurements under cyclic conditions

2016 ◽  
Vol 106 ◽  
pp. 15-21 ◽  
Author(s):  
A. Chirkova ◽  
K.P. Skokov ◽  
L. Schultz ◽  
N.V. Baranov ◽  
O. Gutfleisch ◽  
...  
Keyword(s):  
Temperature Change ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Change ◽  
Direct Measurements

Large electrocaloric response with superior temperature stability in NaNbO3-based relaxor ferroelectrics benefiting from crossover region

2020 ◽  
Author(s):  
Ling Zhang ◽  
Chunlin Zhao ◽  
Ting Zheng ◽  
Jiagang Wu
Keyword(s):  
Temperature Change ◽  
Temperature Stability ◽  
Relaxor Ferroelectrics ◽  
Adiabatic Temperature ◽  
Next Generation ◽  
Crossover Region ◽  
Adiabatic Temperature Change

Electrocaloric refrigeration emerges as a newly-developing technology with potential to be the next generation of coolers. However, the combination of large adiabatic temperature change (ΔT) and good temperature stability remains...

scholarly journals Tunable Magnetocaloric Properties of Gd-Based Alloys by Adding Tb and Doping Fe Elements

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2877 ◽  
Author(s):  
Lingfeng Xu ◽  
Chengyuan Qian ◽  
Yongchang Ai ◽  
Tong Su ◽  
Xueling Hou
Keyword(s):  
Magnetic Field ◽  
Curie Temperature ◽  
Temperature Change ◽  
Indirect Measurement ◽  
Adiabatic Temperature ◽  
Doping Content ◽  
Adiabatic Temperature Change ◽  
Magnetocaloric Properties ◽  
Capacity Calculation ◽  
Low Magnetic Field

In this paper, the magnetocaloric properties of Gd1−xTbx alloys were studied and the optimum composition was determined to be Gd0.73Tb0.27. On the basis of Gd0.73Tb0.27, the influence of different Fe-doping content was discussed and the effect of heat treatment was also investigated. The adiabatic temperature change (ΔTad) obtained by the direct measurement method (under a low magnetic field of 1.2 T) and specific heat capacity calculation method (indirect measurement) was used to characterize the magnetocaloric properties of Gd1−xTbx (x = 0~0.4) and (Gd0.73Tb0.27)1−yFey (y = 0~0.15), and the isothermal magnetic entropy (ΔSM) was also used as a reference parameter for evaluating the magnetocaloric properties of samples together with ΔTad. In Gd1−xTbx alloys, the Curie temperature (Tc) decreased from 293 K (x = 0) to 257 K (x = 0.4) with increasing Tb content, and the Gd0.73Tb0.27 alloy obtained the best adiabatic temperature change, which was ~3.5 K in a magnetic field up to 1.2 T (Tc = 276 K). When the doping content of Fe increased from y = 0 to y = 0.15, the Tc of (Gd0.73Tb0.27)1−yFey (y = 0~0.15) alloys increased significantly from 276 K (y = 0) to 281 K (y = 0.15), and a good magnetocaloric effect was maintained. The annealing of alloys (Gd0.73Tb0.27)1−yFey (y = 0~0.15) at 1073 K for 10 h resulted in an average increase of 0.3 K in the maximum adiabatic temperature change and a slight increase in Tc. This study is of great significance for the study of magnetic refrigeration materials with adjustable Curie temperature in a low magnetic field.

scholarly journals Dynamics of the magnetoelastic phase transition and adiabatic temperature change in Mn1.3Fe0.7P0.5Si0.55

2019 ◽  
Vol 477 ◽  
pp. 287-291 ◽  
Author(s):  
M. Fries ◽  
T. Gottschall ◽  
F. Scheibel ◽  
L. Pfeuffer ◽  
K.P. Skokov ◽  
...  
Keyword(s):  
Phase Transition ◽  
Temperature Change ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Change

Reversibility in the adiabatic temperature-change of Pr0.73Pb0.27MnO3

2013 ◽  
Vol 565 ◽  
pp. 139-143 ◽  
Author(s):  
Selda Kılıç Çetin ◽  
Mehmet Acet ◽  
Ahmet Ekicibil ◽  
Cengiz Sarıkürkçü ◽  
Kerim Kıymaç
Keyword(s):  
Temperature Change ◽  
Adiabatic Temperature ◽  
Adiabatic Temperature Change
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