Design of a Magnetic Cooling Device Using Gadolinium Alloy and Permanent Magnets

2016 ◽  
Author(s):  
Amanie N. Abdelmessih ◽  
Paul W. Bartholomae ◽  
Matthew L. Casillas ◽  
Rocky E. DeLyon ◽  
Joshua F. Flaherty ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetocaloric Effect ◽  
Temperature Change ◽  
Permanent Magnets ◽  
Operating Cost ◽  
Heat Pumps ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Vapor Compression ◽  
Magnetic Cooling

Traditionally, heat pumps and refrigerators utilize the vapor compression cycle to achieve cooling. These vapor compression cycles use hydrochlorofluorocarbons (R134a) as the cycle’s working fluid. This refrigerant contributes to global warming and is expected to be phased out. Consequently, new refrigerants as well as new refrigeration methods need to be developed. The research detailed in this article attempts to implement the magnetocaloric effect of gadolinium alloy in a designed apparatus to lower the temperature of air. Gadolinium alloy has a noticeable magnetocaloric effect within a strong magnetic field (5 T). This research is aimed at producing a noticeable temperature change (2–3 °C) in a relatively smaller magnetic field (1 T) produced with permanent magnets. This work tests the feasibility of magnetic cooling by introducing the design of a magnetic cooling apparatus, using Gadolinium alloy (Gd5Si2Ge2). Small pebbles were used as opposed to a solid plate in order to have an increased surface area to enhance the convection heat transfer process. Permanent magnets were used in the apparatus, to decrease the operating cost. The maximum temperature change encountered in the heat exchanger of the apparatus built was 2.3 °C in a 1 T magnetic field.

Bulk Transition Elements Based Materials for Magnetic Cooling Application

2011 ◽  
Vol 170 ◽  
pp. 248-252 ◽  
Author(s):  
Mohamed Balli ◽  
Osmann Sari ◽  
L. Zamni ◽  
A. Robert ◽  
J. Forchelet ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Composite Material ◽  
Powder Metallurgy ◽  
Magnetocaloric Effect ◽  
Temperature Change ◽  
Room Temperature ◽  
Test Bench ◽  
Transition Elements ◽  
Magnetic Systems ◽  
Magnetic Cooling

In this paper we investigate the performances of two bulk magnetocaloric refrigerants based on La(Fe,Co)13-xSix and prepared by powder metallurgy. Both materials were developed especially for a magnetic cooling machine. We have determined the magnetocaloric effect in term of temperature change under magnetic field using a test-bench with practical running conditions. ΔT was measured under 2 T and close to room temperature range. The obtained results will be compared with those of some reference materials reported in the literature. In addition, a composite material based on La(Fe,Co)13-xSix is proposed for magnetic systems using Ericsson and AMR cycles for refrigeration close to room temperature.

Design and Fabrication of a Magnetocaloric Microcooler

2005 ◽  
Author(s):  
Sangchae Kim ◽  
Bharath Bethala ◽  
Simone Ghirlanda ◽  
Senthil N. Sambandam ◽  
Shekhar Bhansali
Keyword(s):  
Magnetic Field ◽  
Ambient Temperature ◽  
Temperature Change ◽  
Entropy Change ◽  
Temperature Sensors ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Alternative Technology ◽  
Temperature Conditions ◽  
Si Wafer

Magnetocaloric refrigeration is increasingly being explored as an alternative technology for cooling. This paper presents the design and fabrication of a micromachined magnetocaloric cooler. The cooler consists of fluidic microchannels (in a Si wafer), diffused temperature sensors, and a Gd5(Si2Ge2) magnetocaloric refrigeration element. A magnetic field of 1.5 T is applied using an electromagnet to change the entropy of the magnetocaloric element for different ambient temperature conditions ranging from 258 K to 280 K, and the results are discussed. The tests show a maximum temperature change of 7 K on the magnetocaloric element at 258 K. The experimental results co-relate well with the entropy change of the material.

Magnetocaloric as Solid-State Cooling Technique for Energy Saving

2020 ◽  
pp. 226-252
Author(s):  
Ciro Aprea ◽  
Adriana Greco ◽  
Angelo Maiorino ◽  
Claudia Masselli
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
External Magnetic Field ◽  
Magnetocaloric Effect ◽  
Intrinsic Property ◽  
Thermodynamic Cycle ◽  
Refrigeration Cycle ◽  
Vapor Compression ◽  
Cooling Technology ◽  
Active Regeneration

Magnetocaloric is an emerging cooling technology arisen as alternative to vapor compression. The main novelty introduced is the employment of solid-state materials as refrigerants that experiment magnetocaloric effect, an intrinsic property of changing their temperature because of the application of an external magnetic field under adiabatic conditions. The reference thermodynamic cycle is called active magnetocaloric regenerative refrigeration cycle, and it is Brayton-based with active regeneration. In this chapter, this cooling technology is introduced from the fundamental principles up to a description of the state of the art and the goals achieved by researches and investigations.

scholarly journals Calculated and experimental evaluation heat pump distiller on pentane as working substance

2020 ◽  
Vol 324 ◽  
pp. 02007
Author(s):  
Gennady A. Ilyn ◽  
Ilya I. Malafeev ◽  
Vladimir B. Sapojnikov
Keyword(s):  
High Temperature ◽  
High Efficiency ◽  
Recovery Phase ◽  
High Energy ◽  
Heat Pumps ◽  
Working Fluid ◽  
Vapor Compression ◽  
The Cost ◽  
Reliable Methods ◽  
High Temperature Vapor

One of the most common and reliable methods of water treatment is the method of thermal distillation. Despite the reliability of the method, its application is constrained by high energy intensity. The most effective way to reduce the cost of production of distillate is the use of thermal transformers, providing regenerate and heat recovery phase transformations of the distillate. The use of working fluid with the most favorable thermodynamic properties is of paramount importance for the creation of high efficiency thermotransformers. The work is considered working fluid for high-temperature heat pumps and the results of the calculation-experimental study of high-temperature vapor compression heat-pumping distiller on natural working substance n-pentan.

Modeling of Thermo-Magnetic Phenomena in Active Magnetic Regenerators

2013 ◽  
Author(s):  
Paulo V. Trevizoli ◽  
Jader R. Barbosa ◽  
Armando Tura ◽  
Daniel Arnold ◽  
Andrew Rowe
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Solid Phase ◽  
Porous Matrix ◽  
Cooling Capacity ◽  
Working Fluid ◽  
Active Magnetic Regenerator ◽  
Flow And Heat Transfer ◽  
Magnetic Cooling ◽  
Matrix Heat Exchanger

The active magnetic regenerator (AMR) is at the heart of the thermo-magnetic Brayton cooling cycle. It consists of a porous matrix heat exchanger whose solid phase is a magnetocaloric material (solid refrigerant) that undergoes a reversible magnetic phase transition when subjected to a changing magnetic field. The cooling capacity of the cycle is proportional to the mass of solid refrigerant, operating frequency, volumetric displacement of the working fluid (generally an aqueous solution) and regenerator effectiveness. AMRs can be modeled via a porous media approach and a model has been developed to simulate the time-dependent fluid flow and heat transfer processes. Gadolinium (Gd) is usually adopted as a reference material for magnetic cooling at near room temperature and, in this study, its magnetic temperature change and physical properties were accounted for using a combination of experimental data and the Weiss-Debye-Sommerfeld theory. In this paper, the influence of the applied magnetic field waveform and of demagnetizing effects on the AMR performance is investigated numerically. An evaluation of the model is also carried out in the light of a comparison against experimental data for a regenerator containing spherical Gd particles.

scholarly journals Fluid Retrofit for Existing Vapor Compression Refrigeration Systems and Heat Pumps: Evaluation of Different Models

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2417
Author(s):  
Dennis Roskosch ◽  
Valerius Venzik ◽  
Burak Atakan
Keyword(s):  
Selection Procedure ◽  
Heat Pumps ◽  
Working Fluid ◽  
Plant Design ◽  
Vapor Compression ◽  
Working Fluids ◽  
Simulation Tools ◽  
Pump Test ◽  
Vapor Compression Refrigeration ◽  
Very High

The global warming potential of many working fluids used nowadays for vapor compression refrigeration systems and heat pumps is very high. Many of such fluids, which are used in currently operating refrigerators and heat pumps, will have to be replaced. In order to avoid a redesign of the system, it would be very helpful if efficient and ecological alternative working fluids for a given plant could be found. With modern process simulation tools such a selection procedure seems possible. However, it remains unclear how detailed such a model of a concrete plant design has to be to obtain a reliable working fluid ranking. A vapor compression heat pump test-rig is used as an example and simulated by thermodynamic models with different levels of complexity to investigate this question. Experimental results for numerous working fluids are compared with models of different complexity. Simple cycle calculations, as often used in the literature, lead to incorrect results regarding the efficiency and are not recommended to find replacement fluids for existing plants. Adding a compressor model improves the simulations significantly and leads to reliable fluid rankings but this is not sufficient to judge the adequacy of the heat exchanger sizes and whether a given cooling or heating task can be fulfilled with a certain fluid. With a model of highest complexity, including an extensive model for the heat exchangers, this question can also be answered.

Simple Set-Up for Adiabatic Measurements of Magnetocaloric Effect

2015 ◽  
Vol 644 ◽  
pp. 215-218 ◽  
Author(s):  
P. Álvarez-Alonso ◽  
J. López-García ◽  
G. Daniel-Perez ◽  
D. Salazar ◽  
P. Lázpita ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetocaloric Effect ◽  
Temperature Change ◽  
Heusler Alloy ◽  
Cost Effective ◽  
Adiabatic Temperature ◽  
Magnetic Phase Transitions ◽  
Adiabatic Temperature Change ◽  
Set Up ◽  
The Magnetic Field

We present a cost-effective and robust set-up designed to measure directly the magnetic field-induced adiabatic temperature change. The system uses a piston to introduce/remove the sample to/from the magnetic field (μ0∆His up to 1.7T) created by an ordinary electromagnet. The temperature of the sample is controlled by a double pipe heat exchanger operating by the electrical heater and air flow circulation from a Dewar with liquid nitrogen to the sample holder assembly.We have measured the adiabatic temperature change, ΔTad, of two polycrystalline samples: Gd and Ni50Mn35In15Heusler alloy. At the second-order magnetic phase transitions (18oC for Gd and 42oC for Ni50Mn35In15), ΔTadunder μ0∆H=1.7T are 3.8±0.1oC for Gd and 1.9±0.1oC for Ni50Mn35In15. The Heusler alloy shows an inverse magnetocaloric effect: ΔTadis-1.5±0.1oC on cooling and-1.6±0.1oC on heating at the martensitic transformation temperatures of ~24oC and ~29oC, respectively.

Analysis and Development of a Magnetocaloric Pump for Electronic Cooling Applications Using a Mn-Zn Ferrite Ferrofluid

2008 ◽  
Author(s):  
Jorge Gustavo Gutierrez ◽  
Miguel Riccetti
Keyword(s):  
Magnetic Field ◽  
Curie Temperature ◽  
Pressure Gradient ◽  
Temperature Change ◽  
Variable Magnetic Field ◽  
Magnetic Pressure ◽  
Working Fluid ◽  
Scaling Analysis ◽  
Field Source ◽  
Zn Ferrite

A device able to pump a fluid with no moving mechanical parts represents a very encouraging alternative since such device would be practically maintenance free. A magnetocaloric pump could achieve this purpose by providing a magnetic pressure gradient to a ferrofluid placed inside a magnetic field while experiencing a temperature change. If the temperature change is produced by extracting heat out of an element that needs refrigeration, coupling this generated heat with the magnetocaloric pump will result in a passive cooling system. For applications near ambient temperature the ferrofluid must have specific characteristics such as low “Curie temperature”, high pyromagnetic coefficient, high thermal conductivity and low viscosity. This work presents an analysis of the ferrohydrodynamic governing equations, emphasizing the importance of the Kelvin force in the magnetocaloric pump analysis. The general equations are simplified and scaled to show which parameters are important in the generation of the magnetic pressure gradient. Based on the scaling analysis, a variable magnetic field and a higher saturation magnetization is needed to generate a higher magnetic pressure gradient. The working fluid used is an aqueous Mn0.5Zn0.5Fe2O4 ferrite ferrofluid synthesized by the co-precipitation technique. This ferrite shows lower “Curie temperature” than commercially available magnetite. Important issues in the design of a magnetocaloric pump prototype with a variable magnetic field source are also discussed.

scholarly journals Identification of Existing Challenges and Future Trends for the Utilization of Ammonia-Water Absorption–Compression Heat Pumps at High Temperature Operation

2021 ◽  
Vol 11 (10) ◽  
pp. 4635
Author(s):  
Marcel Ulrich Ahrens ◽  
Maximilian Loth ◽  
Ignat Tolstorebrov ◽  
Armin Hafner ◽  
Stephan Kabelac ◽  
...  
Keyword(s):  
High Temperature ◽  
Water Absorption ◽  
Industrial Sector ◽  
Heat Pumps ◽  
Working Fluid ◽  
Large Temperature ◽  
Future Trends ◽  
Ammonia Water ◽  
Starting Point ◽  
High Temperature Operation

Decarbonization of the industrial sector is one of the most important keys to reducing global warming. Energy demands and associated emissions in the industrial sector are continuously increasing. The utilization of high temperature heat pumps (HTHPs) operating with natural fluids presents an environmentally friendly solution with great potential to increase energy efficiency and reduce emissions in industrial processes. Ammonia-water absorption–compression heat pumps (ACHPs) combine the technologies of an absorption and vapor compression heat pump using a zeotropic mixture of ammonia and water as working fluid. The given characteristics, such as the ability to achieve high sink temperatures with comparably large temperature lifts and high coefficient of performance (COP) make the ACHP interesting for utilization in various industrial high temperature applications. This work reviews the state of technology and identifies existing challenges based on conducted experimental investigations. In this context, 23 references with capacities ranging from 1.4 kW to 4500 kW are evaluated, achieving sink outlet temperatures from 45 °C to 115 °C and COPs from 1.4 to 11.3. Existing challenges are identified for the compressor concerning discharge temperature and lubrication, for the absorber and desorber design for operation and liquid–vapor mixing and distribution and the choice of solution pump. Recent developments and promising solutions are then highlighted and presented in a comprehensive overview. Finally, future trends for further studies are discussed. The purpose of this study is to serve as a starting point for further research by connecting theoretical approaches, possible solutions and experimental results as a resource for further developments of ammonia-water ACHP systems at high temperature operation.

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

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