Review on research of room temperature magnetic refrigeration

Room temperature magnetic refrigeration is a new highly efficient and environmentally protective technology. Although it has not been maturely developed, it shows great applicable prosperity and seems to be a substitute for the traditional vapor compression technology. In this paper, the concept of magnetocaloric effect is explained. The development of the magnetic material, magnetic refrigeration cycles, magnetic field and the regenerator of room temperature magnetic refrigeration is introduced. Finally some typical room temperature magnetic refrigeration prototypes are reviewed.     

Finite-time power limit for solar-radiant Ericsson engines in space applications

The power output and thermal efficiency of a finite-time optimized solar-radiant Ericsson heat engine is studied. The thermodynamic model adopted is a regenerative gas Ericsson cycle coupled to a heat source and heat sink by radiant heat transfer. Both the heat source and heat sink have infinite heat capacity rates. Mathematical expressions for optimum power and the efficiency at optimum power are obtained for the cycle based on higher and lower temperature bounds. The results of this theoretical work provide a base line criteria for use in the performance evaluation and design of such engines as well as for use in performance comparisons with existing extra-terrestrial solar power plants.     

热阻和非理想回热对铁电埃里克森制冷循环的(火用)经济优化性能的影响

应用有限时间炯分析法,研究热阻和非理想回热对铁电埃里克森制冷循环的炯经济优化性能的影响。基于铁电晶体的热力学特性,考虑线性传热规律,得到铁电埃里克森制冷循环的基本优化关系及其他性能参数,所得结论可为铁电埃里克森制冷循环的优化设计和性能改善提供些指导。     

顺磁质Ericsson制冷循环不具有理想回热条件

给出理想回热的判据，并应用了它证明了顺磁南Ｅｒｉｃｓｓｏｎ制冷循环不具有理想回热的条件。此外，还指出了有关研究中的一些错误。     

热阻和回热损失对埃里克森循环性能的影响

建立受热阻和回热损失影响的埃里克森循环模型,以输出功率为目标函数,导出循环的基本优化关系式,由此获得循环的特性曲线,并对特殊的工况点作了详细的讨论,从而得到一些新的结论。     

Otherwise Engaged: New Projects in Interactive Design

What are the possibilities of interactive technologies delivering a new level of social engagement in architecture? Taking 2002, with the ETH Ada project and Diller & Scofidio's Braincoat project, as an important watershed, Mark Garcia reviews the advances that have been made per se, and with four projects in particular, in socially interactive spatial design. Copyright © 2007 John Wiley & Sons, Ltd.     

Applicability of scroll expander and compressor to an external power engine: Conceptual design and performance analysis

A scroll expander and scroll compressor for a 10‐kW class Ericsson engine utilizing solar energy as heat source has been suggested. Orbiting scroll members of the expander and compressor were designed to have a base plate with double‐sided wrap structure for compact size and axial gas force cancellation. For axial compliance of the scroll machines, a back pressure chamber was created on each fixed scroll. In order to compensate for the thermal expansion, flexible coupling between the orbiting scroll base plate and the scroll plate holders and sliding keys between the fixed scroll and the supporting frame were designed. Common shafts were shared by the expander and compressor for direct power transmission. For high‐ and low‐side pressures of 6 and 2.5 MPa, respectively, and expander inlet temperature of 700°C, the proposed engine efficiency was estimated to be 7.3%. The engine efficiency strongly depends on the expander and compressor efficiencies as well as on the regenerator efficiency. The shaft output of the designed scroll expander was calculated to be 38.84 kW, while the input power for the scroll compressor was 27.97 kW, yielding 10.87 kW for the engine output. Copyright © 2011 John Wiley & Sons, Ltd.     

爱立信程控交换机维护及故障处理要点经验谈

文章从实际运行维护出发,详述了爱立信程控交换机应用中出现的常见问题及维护方法,并对常见故障的处理以及升级固件排除现有隐患进行了分析与总结。     

铁电埃里克森制冷机的基本优化关系

给出了一种铁电埃里克森制冷机模型，利用铁电晶体的热力学性质，应用有限时间热力学理论，探讨热阻及非理想回热这一类铁电埃里克森制冷机的影响，所得结论可为回热式铁电制冷机的研制和设计提供理论指导。     

Ecological optimization of an irreversible Ericsson cryogenic refrigerator cycle

The ecological optimization and parametric study of an irreversible Ericsson cryogenic refrigerator cycle with finite heat capacities of external reservoirs is studied. The ecological function is defined as the cooling load minus the loss of the cooling load (the irreversibility) due to the entropy generation rate. The ecological function is optimized with respect to working fluid temperatures and the values of the cooling load, power input, the loss rate of the cooling load and COP are calculated for a typical set of operating parameters. The effects of different operating parameters on the ecological function, cooling load, the loss rate of the cooling load and COP are studied. The loss rate of the cooling load and the power input are found to be increasing functions of the cycle temperature ratio and decreasing functions of COP while the COP is found to be a decreasing function of the cycle temperature ratio. On the other hand, there exist the optimal values of the cycle temperature ratio and COP at which the ecological function and cooling load attain their maximum values. Also the ecological function and the cooling load are found to be increasing functions of the sink‐side heat capacitance rate and the effectiveness on the source‐, sink‐, and regenerative‐side heat exchangers while the decreasing functions of the source‐side heat capacitance rate. Copyright © 2005 John Wiley & Sons, Ltd.