Optimization of Regenerators for AMRR Systems

Nellis, Gregory¹  Klein, Sanford¹  Brey, William¹  Moine, Alexandra¹  Nielson, Kaspar¹ 

[1] University of Wisconsin, Madison, WI (United States)

关键词: magnetic refrigeration;    regeneration;    AMRR;    hysteresis;   

DOI  :  10.2172/1184834
RP-ID  :  DOE-UW--0003850
PID  :  OSTI ID: 1184834

学科分类：能源（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Active Magnetic Regenerative Refrigeration (AMRR) systems have no direct global warming potential or ozone depletion potential and hold the potential for providing refrigeration with efficiencies that are equal to or greater than the vapor compression systems used today. The work carried out in this project has developed and improved modeling tools that can be used to optimize and evaluate the magnetocaloric materials and geometric structure of the regenerator beds required for AMRR Systems. There has been an explosion in the development of magnetocaloric materials for AMRR systems over the past few decades. The most attractive materials, based on the magnitude of the measured magnetocaloric effect, tend to also have large amounts of hysteresis. This project has provided for the first time a thermodynamically consistent method for evaluating these hysteretic materials in the context of an AMRR cycle. An additional, practical challenge that has been identified for AMRR systems is related to the participation of the regenerator wall in the cyclic process. The impact of housing heat capacity on both passive and active regenerative systems has been studied and clarified within this project. This report is divided into two parts corresponding to these two efforts. Part 1 describes the work related to modeling magnetic hysteresis while Part 2 discusses the modeling of the heat capacity of the housing. A key outcome of this project is the development of a publically available modeling tool that allows researchers to identify a truly optimal magnetocaloric refrigerant. Typically, the refrigeration potential of a magnetocaloric material is judged entirely based on the magnitude of the magnetocaloric effect and other properties of the material that are deemed unimportant. This project has shown that a material with a large magnetocaloric effect (as evidenced, for example, by a large adiabatic temperature change) may not be optimal when it is accompanied by a large hysteresis. The trade-off between these various material properties and the proper design of an AMRR system can only be evaluated correctly using the comprehensive, physics-based model developed by this project. The development of these modeling tools and optimization studies will provide the knowledge base that is required to achieve transformational discoveries. The widespread adoption of AMRR technology will change the character of energy demand in this country and provide manufacturing jobs as well as employment associated with retrofitting existing HVAC&R applications.