Proceedings of the 20th International Cryogenic Engineering Conference

This book is the first in English being entirely dedicated to Miniature Joule-Thomson Cryocooling. The category of Joule-Thomson (JT) cryocoolers takes us back to the roots of cryogenics, in 1895, with figures like Linde and Hampson. The "cold finger" of these cryocoolers is compact, lacks moving parts, and sustains a large heat flux extraction at a steady temperature. Potentially, they cool down unbeatably fast. For example, cooling to below 100 K (minus 173 Celsius) might be accomplished within only a few seconds by liquefying argon. A level of about 120 K can be reached almost instantly with krypton. Indeed, the species of coolant plays a central role dictating the size, the intensity and the level of cryocooling. It is the JT effect that drives these cryocoolers and reflects the deviation of the "real" gas from the ideal gas properties. The nine chapters of the book are arranged in five parts. •The Common Principle of Cyrocoolers shared across the broad variety of cryocooler types •Theoretical Aspects: the JT effect and its inversion, cooling potential of coolants, the liquefaction process, sizing of heat exchangers, level of pressurization, discharge of pressure vessels • Practical Aspects: modes of operation (fast cooldown, continuous, multi-staging, hybrid cryocoolers), pressure sources, configuration, construction and technologies, flow adjustment, MEMS, open and closed cycle, cooldown process and similarity, transient behavior • Mixed Coolant cryocooling: theory, practice and applications • Special Topics: real gas choked flow rates, gas purity, clog formation, optimal fixed orifice, modeling, cryosurgical devices, warming by the inverse JT effect The theoretical aspects may be of interest not only to those working with cryocoolers but also for others with a general interest in "real" gas thermodynamics, such as, for example, the inversion of the JT effect in its differential and integral forms, and the exceptional behavior of the quantum gases. A detailed list of references for each chapter comprises a broad literature survey. It consists of more than 1,200 relevant publications and 450 related patents. The systematically organized content, arranged under a thorough hierarchy of headings, supported by 227 figures and 41 tables, and accompanied by various chronological notes of evolution, enables readers a friendly interaction with the book. Dr. Ben-Zion Maytal is a Senior Researcher at Rafael-Advanced Defense Systems, Ltd., and an Adjunct Senior Teaching Fellow at the Technion-Israel Institute of Technology, Haifa, Israel. Prof. John M. Pfotenhauer holds a joint appointment in the Departments of Mechanical Engineering and Engineering Physics at the University of Wisconsin - Madison.

This book contains the proceedings of the 16th ICEC/ICMC Conference, held in Kitakyushu, Japan, on 20th-24th May 1996. The Proceedings are presented in three volumes containing a total of 476 papers from 1484 authors. The proceedings covers the main areas of: Large Scale Refrigeration. Cryocoolers. Cryogenic Engineering. Space Cryogenics. Application of Superconductivity. Oxide Superconductors. Metallic Superconductors. Metallic Materials. Non Metallic Materials. In addition there are seven Plenary Lectures covering such diverse topics as commercialization of high-Tc superconductors, the continuing development of the Maglev system in Japan, and the Large Hadron Collider project. The Proceedings comprise an excellent and up-to-date summary of research and development in the fields of Cryogenics and Superconductivity.

This book serves as an introduction to cryocooler technology and describes the principle applications of cryocoolers across a broad range of fields. It covers the specific requirements of these applications, and describes how the advantages and disadvantages of different cryocooler systems are taken into consideration. For example, Stirling coolers tend to be used only in space applications because of their high coefficient of performance, low weight and proven reliability, whilst Gifford-McMahon coolers are used for ground applications, such as in cryopumps and MRI shield cooling applications. Joule-Thomson cryocoolers are used in missile technology because of the fast cool down requirements. The cryocooler field is fast developing and the number of applications are growing because of the increasing costs of the cryogens such as Helium and Neon. The first chapter of the book introduces the different types of cryocoolers, their classification, working principles, and their design aspects, and briefly mentions some of the applications of these systems. This introductory chapter is followed by a number of contributions from prominent international researchers, each describing a specific field of application, the cooling requirements and the cryocooler systems employed. These areas of application include gas liquefaction, space technology, medical science, dilution refrigerators, missile systems, and physics research including particle accelerators. Each chapter describes the cooling requirements based on the end use, the approximate cooling load calculations, the criteria for cryocooler selection, the arrangement for cryocooler placement, the connection of the cooler to the object to be cooled, and includes genuine case studies. Intended primarily for researchers working on cryocoolers, the book will also serve as an introduction to cryocooler technology for students, and a useful reference for those using cryocooler systems in any area of application.