Magnetocaloric Properties Desired for Magnetic Refrigeration System near Room Temperature

2011 ◽  
Vol 1310 ◽  
Author(s):  
H. Wada
Keyword(s):  
Room Temperature ◽  
Composite Layer ◽  
Cooling Capacity ◽  
Magnetic Refrigeration ◽  
Experimental Results ◽  
Refrigeration System ◽  
Layer Material ◽  
Magnetic Refrigerant ◽  
Magnetocaloric Properties

ABSTRACTIn order to realize the magnetic refrigeration system, it is necessary to develop a 100 W class refrigerator with COP > 7.5. This requires us to find new magnetic refrigerant materials, of which cooling capacity is 2.5 times higher than that of Gd. In this paper, first we discuss the cooling capacity of magnetic refrigerant materials to achieve COP = 7.5. Then, we compare the experimental results of MnAsSb, MnFe(PGe) and La(FeCoSi)13 compounds with the calculated cooling capacity. It is suggested that a composite layer material of MnFe(PGe) would show excellent cooling capacity in the temperature span of 20 K.

The Magnetic Entropy Changes in Gd1-xCrx Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 2267-2270 ◽  
Author(s):  
Song Ling Huang ◽  
Dun Hui Wang ◽  
Zhi Da Han ◽  
S.K. Ren ◽  
Zheng Hua Su ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Room Temperature ◽  
Magnetic Refrigeration ◽  
Magnetic Entropy ◽  
Entropy Changes ◽  
Arc Melting ◽  
Magnetic Refrigerant ◽  
Room Temperature Magnetic Refrigeration ◽  
High Level ◽  
Curie Temperatures

A series of Gd1-xCrx (x=0.01,0.03,0.05 and 0.07) alloys have been prepared by arc melting. After introducing a small quantity of Cr into Gd, the Curie temperatures of these alloys increase. Magnetic entropy changes at the Curie temperature of Gd1-xCrx (x=0.01, 0.03, 0.05) alloys are nearly the same as that of Gd. However, compared with Gd, the magnetic entropy changes of Gd1-xCrx (x=0.01, 0.03, 0.05) alloys remain at a high level in a wider temperature range. So Gd1-xCrx (x=0.01, 0.03, 0.05) alloys are more suitable as magnetic refrigerant to be used in Ericsson Recycle for room temperature magnetic refrigeration. Our results and the fact that Cr is quite cheaper than Gd, suggest that Gd1-xCrx alloys maybe utilized as refrigerant in room temperature magnetic refrigeration.

scholarly journals Mathematical Modelling of Active Magnetic Regenerator Refrigeration System for Design Considerations

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6301
Author(s):  
Aref Effatpisheh ◽  
Amir Vadiee ◽  
Behzad A. Monfared
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Single Layer ◽  
Cooling Capacity ◽  
Magnetic Refrigeration ◽  
Maximum Pressure ◽  
Refrigeration System ◽  
Design Considerations ◽  
Active Magnetic Regenerator

A magnetic refrigeration system has the potential to alternate the compression system with respect to environmental compatibility. Refrigeration systems currently operate on the basis of the expansion and compression processes, while active magnetic refrigeration systems operate based on the magnetocaloric effect. In this study, a single layer of Gd was used as the magnetocaloric material for six-packed-sphere regenerators. A one-dimensional numerical model was utilized to simulate the magnetic refrigeration system and determine the optimum parameters. The optimum mass flow rate and maximum cooling capacity at frequency of 4 Hz are 3 L·min−1 and 580 W, respectively. The results show that the maximum pressure drop increased by 1400 W at a frequency of 4 Hz and mass flow rate of 5 L·min−1. In this study, we consider the refrigeration system in terms of the design considerations, conduct a parametric study, and determine the effect of various parameters on the performance of the system.

Room temperature magnetocaloric properties of Ni substituted La0.67Sr0.33MnO3

2013 ◽  
Vol 19 ◽  
pp. 130-135 ◽  
Author(s):  
C.P. Reshmi ◽  
S. Savitha Pillai ◽  
K.G. Suresh ◽  
Manoj Raama Varma
Keyword(s):  
Room Temperature ◽  
Magnetocaloric Properties

Enhancement of magnetocaloric properties near room temperature in Ga-doped Ni50Mn34.5In15.5 Heusler-type alloy

2012 ◽  
Vol 111 (10) ◽  
pp. 103902 ◽  
Author(s):  
A. Y. Takeuchi ◽  
C. E. Guimarães ◽  
E. C. Passamani ◽  
C. Larica
Keyword(s):  
Room Temperature ◽  
Type Alloy ◽  
Magnetocaloric Properties

Tailoring the magnetostructural transition and magnetocaloric properties around room temperature: In-doped Ni-Mn-Ga alloys

2014 ◽  
Vol 105 (11) ◽  
pp. 112402 ◽  
Author(s):  
Linfang Zhang ◽  
Jingmin Wang ◽  
Hui Hua ◽  
Chengbao Jiang ◽  
Huibin Xu
Keyword(s):  
Room Temperature ◽  
Magnetostructural Transition ◽  
Magnetocaloric Properties

Bending Ratcheting Behavior of Zircaloy-4 Alloy at Room Temperature

2013 ◽  
Vol 690-693 ◽  
pp. 1713-1717 ◽  
Author(s):  
Hong Qiang Guo ◽  
Hua Li ◽  
Yi Chen Sun ◽  
Wei Wei Yu
Keyword(s):  
Room Temperature ◽  
Stress Amplitude ◽  
Experimental Results ◽  
Strain Level ◽  
Mean Stress ◽  
Cyclic Tests ◽  
Ratcheting Strain

In this paper, a series of bending cyclic tests under stress controlled were conducted at room temperature on Zircaloy-4 (Zr-4) to investigate its bending ratcheting behavior. The effects of mean stress and stress amplitude on the bending ratcheting behavior were experimentally studied, respectively. The experimental results show that the ratcheting strain of the material is very sensitive to mean stress and stress amplitude. It can be concluded that ratcheting strain level increases with increasing mean stress and stress amplitude.

Study on Expander-Auxiliary Compressor Unit Used in Refrigeration System

2011 ◽  
Vol 354-355 ◽  
pp. 811-818
Author(s):  
Tao He ◽  
Zhi Yuan Wang ◽  
Yu Qing Xue
Keyword(s):  
Energy Recovery ◽  
Rotation Speed ◽  
Cooling Capacity ◽  
Compressor Unit ◽  
Performance Parameters ◽  
Refrigeration System ◽  
Two Phase ◽  
Speed Up ◽  
Testing Condition ◽  
Auxiliary Unit

The throttling valve used in the refrigeration system always causes energy loss. In this paper, an energy recovery device in the refrigeration system which was composed of an expander-auxiliary compressor unit to replace the throttling valve was investigated. On the basis of thermodynamic analysis, two typical arrangements which the auxiliary compressor was connected to the main compressor of the refrigeration system were compared and the system performance parameters were discussed. A prototype of an expander-auxiliary unit was manufactured to observe the expander performance using R410A as refrigerant. The results showed the reliability of the unit working in the two-phase flow condition with the rotation speed up to 21020 rpm. And the maximum increases in the cooling capacity by 3.9% and COP by 3.2% could be obtained under the testing condition.

Structures and phase transitions in barium sodium niobate tungsten bronze (BNN)

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Thomas A. Whittle ◽  
Christopher J. Howard ◽  
Siegbert Schmid
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Tungsten Bronze ◽  
Standard Setting ◽  
Experimental Results ◽  
Temperature Structure ◽  
Sodium Niobate ◽  
Tetragonal Tungsten Bronze ◽  
Space Group ◽  
The Subject

The room-temperature structure of the filled tetragonal tungsten bronze, Ba2NaNb5O15 (BNN), has been the subject of a number of studies, and these studies have given an almost corresponding number of different results. From a group theoretical examination of the different possibilities and a review of the published experimental results we conclude that the room-temperature structure is that proposed by Labbé et al. [J. Phys. Condens. Matter (1989), 2, 25–43] in the space group Bbm2 (Ama2 in standard setting) on a 2\sqrt{2}a × \sqrt{2}a × 2c cell. Upon heating, the structure remains ferroelectric but becomes tetragonal (space group P4bm) at 550 K, then paraelectric (space group P4/mbm) at and above 860 K.

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