scholarly journals Giant multiple caloric effects in charge transition ferrimagnet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoshihisa Kosugi ◽  
Masato Goto ◽  
Zhenhong Tan ◽  
Daisuke Kan ◽  
Masahiko Isobe ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Entropy Change ◽  
Vapor Compression ◽  
Cooling Systems ◽  
Environment Friendly ◽  
Temperature Changes ◽  
First Order ◽  
Vapor Compression Cooling ◽  
Future Technologies ◽  
Kbar Pressure

AbstractCaloric effects of solids can provide us with innovative refrigeration systems more efficient and environment-friendly than the widely-used conventional vapor-compression cooling systems. Exploring novel caloric materials is challenging but critically important in developing future technologies. Here we discovered that the quadruple perovskite structure ferrimagnet BiCu3Cr4O12 shows large multiple caloric effects at the first-order charge transition occurring around 190 K. Large latent heat and the corresponding isothermal entropy change, 28.2 J K−1 kg−1, can be utilized by applying both magnetic fields (a magnetocaloric effect) and pressure (a barocaloric effect). Adiabatic temperature changes reach 3.9 K for the 50 kOe magnetic field and 4.8 K for the 4.9 kbar pressure, and thus highly efficient thermal controls are achieved in multiple ways.

scholarly journals Reversibility of the Magnetocaloric Effect in the Bean-Rodbell Model

2021 ◽  
Vol 7 (5) ◽  
pp. 60
Author(s):  
Luis M. Moreno-Ramírez ◽  
Victorino Franco
Keyword(s):  
Magnetic Field ◽  
Thermal Hysteresis ◽  
Entropy Change ◽  
Second Order ◽  
Zero Field ◽  
First Order ◽  
Magnetic Field Change ◽  
Magnetocaloric Materials ◽  
Moderate Magnetic Field ◽  
The Magnetic Field

The applicability of magnetocaloric materials is limited by irreversibility. In this work, we evaluate the reversible magnetocaloric response associated with magnetoelastic transitions in the framework of the Bean-Rodbell model. This model allows the description of both second- and first-order magnetoelastic transitions by the modification of the η parameter (η<1 for second-order and η>1 for first-order ones). The response is quantified via the Temperature-averaged Entropy Change (TEC), which has been shown to be an easy and effective figure of merit for magnetocaloric materials. A strong magnetic field dependence of TEC is found for first-order transitions, having a significant increase when the magnetic field is large enough to overcome the thermal hysteresis of the material observed at zero field. This field value, as well as the magnetic field evolution of the transition temperature, strongly depend on the atomic magnetic moment of the material. For a moderate magnetic field change of 2 T, first-order transitions with η≈1.3−1.8 have better TEC than those corresponding to stronger first-order transitions and even second-order ones.

Spin reorientation transition: phase diagrams and entropy change

2011 ◽  
Vol 1310 ◽  
Author(s):  
Vittorio Basso ◽  
Carlo P. Sasso ◽  
Michaela Kuepferling
Keyword(s):  
Magnetic Field ◽  
Easy Axis ◽  
Entropy Change ◽  
Rotating Magnetic Field ◽  
Spin Reorientation ◽  
Temperature Dependent ◽  
First Order ◽  
Crystalline Anisotropy ◽  
The Magnetic Field ◽  
Magneto Crystalline Anisotropy

ABSTRACTIn this paper we review the phase diagram and derive the entropy change for spin reorientation transitions by considering first order magnetization process theory with temperature dependent magneto-crystalline anisotropy constants. We derive the magnetic field-induced entropy change Δs for a transition between easy axis and easy plane, showing that for alternating magnetic field, Δs has a change of sign at the reorientation temperature, while for rotating magnetic field its sign is definite. We apply the model to CoZn W-type barium ferrite.

scholarly journals SISTEM KONTROL SUHU PENYIMPAN BUAH-SAYUR PADA MESIN PENDINGIN TERMOELEKTRIK

2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Rofan Aziz ◽  
Muh Tanwirul Afkar ◽  
Sunanto Sunanto ◽  
Karsid Karsid
Keyword(s):  
Control System ◽  
Temperature Control ◽  
Fruits And Vegetables ◽  
Coefficient Of Performance ◽  
Temperature Control System ◽  
Vapor Compression ◽  
Cooling Systems ◽  
High Coefficient ◽  
Conventional Cooling ◽  
Vapor Compression Cooling

Conventional cooling systems based on vapor compression have a high coefficient of performance (COP). However shortage of vapor compression cooling systems still using refrigerants that have detrimental effects on the environment. For that purpose, the research of fruit and vegetable storage machine using thermoelectric system TEC1-12706 with temperature control system using arduino. In this study the temperature in the cabin can be stable at 15° C and still feasible for use as a storage of fruits and vegetables.

Performance Enhancement of Solar Air Conditioners Using Hybrid Heat Rejection System

2019 ◽  
Author(s):  
Abdul Ahad Iqbal ◽  
Ali Al-Alili
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Vapor Compression ◽  
Summer Period ◽  
Cooling Systems ◽  
Hybrid Cooling ◽  
Vapor Compression Cooling ◽  
Air Conditioning Systems ◽  
Sorption Systems ◽  
Dry Cooling

Abstract The performance of air conditioning systems is highly dependent on the environmental conditions of the high pressure side, where heat is rejected to the environment. Air conditioning systems utilize dry cooling systems which often don’t provide adequate cooling during peak cooling periods, or wet cooling systems which consume a lot of water. In this study, a novel hybrid cooling system that can provide both wet and dry cooling was modelled in TRNSYS, and used to provide cooling to closed sorption air conditioning systems. The performance of these systems with the hybrid cooling system was compared to the performance of a standard vapor compression cooling system being cooled by a dry cooling system. The COPsol of the vapor compression cooling system exhibited a decrease of almost 26% during the summer period, whereas the COPsol of the sorption systems increased by around 30%. Similarly, the cooling capacity of the vapor compression cooling system dropped by almost 5%, and for the sorption systems, it increased by around 20% during the summer period.

Hybrid sorption-vapor compression cooling systems: A comprehensive overview

2021 ◽  
Vol 143 ◽  
pp. 110912
Author(s):  
Mohamed G. Gado ◽  
Shinichi Ookawara ◽  
Sameh Nada ◽  
Ibrahim I. El-Sharkawy
Keyword(s):  
Vapor Compression ◽  
Comprehensive Overview ◽  
Cooling Systems ◽  
Vapor Compression Cooling

First-Principle Dynamic Modeling of a Linear Micro-Compressor

2013 ◽  
Author(s):  
Mahmoud Alzoubi ◽  
Guanqiu Li ◽  
TieJun Zhang
Keyword(s):  
High Performance ◽  
Electronics Cooling ◽  
First Principle ◽  
Vapor Compression ◽  
Transient Pressure ◽  
Piston Velocity ◽  
Temperature Changes ◽  
Temperature Trends ◽  
Vapor Compression Cooling ◽  
Main Component

Compressor is the main component in the Vapor Compression Cooling cycle (VCC). Comparing with scroll and screw compressors, linear compressors are used in miniature-scale VCC cycle for small and portable applications such as electronics cooling systems. Linear micro-compressors exhibit high performance because they have fewer moving components and less frictional losses than other types. In this paper, a first-principle dynamic model has been developed to characterize the transient pressure, temperature, and fluid flow inside a linear micro-compressor. A theoretical analysis and a parametric study have been performed in this research to reveal the influence of the piston motion profile on the pressure and temperature changes inside the compression chamber. Moreover, the effect of changing piston velocity on the flow rate, pressure and temperature trends has been studied in this research.

scholarly journals External-Field-Induced Phase Transformation and Associated Properties in a Ni50Mn34Fe3In13 Metamagnetic Shape Memory Wire

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 309
Author(s):  
Zhen Chen ◽  
Daoyong Cong ◽  
Shilei Li ◽  
Yin Zhang ◽  
Shaohui Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transformation ◽  
Tensile Stress ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Entropy Change ◽  
Magnetic Actuation ◽  
Recoverable Strain ◽  
First Order ◽  
First Order Phase

Metamagnetic shape memory alloys exhibit a series of intriguing multifunctional properties and have great potential for applications in magnetic actuation, sensing and magnetic refrigeration. However, the poor mechanical properties of these alloys with hardly any tensile deformability seriously limit their practical application. In the present work, we developed a Ni-Fe-Mn-In microwire that exhibits both a giant, tensile superelasticity and a magnetic-field-induced first-order phase transformation. The recoverable strain of superelasticity is more than 20% in the temperature range of 233–283 K, which is the highest recoverable strain reported heretofore in Ni-Mn-based shape memory alloys (SMAs). Moreover, the present microwire exhibits a large shape memory effect with a recoverable strain of up to 13.9% under the constant tensile stress of 225 MPa. As a result of the magnetic-field-induced first-order phase transformation, a large reversible magnetocaloric effect with an isothermal entropy change ΔSm of 15.1 J kg−1 K−1 for a field change from 0.2 T to 5 T was achieved in this microwire. The realization of both magnetic-field and tensile-stress-induced transformations confers on this microwire great potential for application in miniature multi-functional devices and provides an opportunity for multi-functional property optimization under coupled multiple fields.

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