Low-temperature superconductivity and space exploration urgently require compact， highly reliable， and long-lifespan cooling technologies that operate in the liquid-helium temperature range. Multistage Stirling-type pulse tube cryocoolers are a promising solution. In this study， a thermally coupled three-stage Stirling-type pulse tube cryocooler was designed and constructed. The system employs a two high-frequency （70 Hz） Stirling cryocooler （model TC3130， Lihan） to precool the third stage， thus providing cooling capacities of 5 W and 2 W at 70 K and 32 K， respectively. For the third stage， simplified models were first established using Sage to determine the key operating parameters， including the operating frequency， average pressure， and precooling temperature. The third stage was fully simulated， followed by the final design and experimental set up. Experimental results show that under an average pressure of 1.4 MPa， a frequency of 21 Hz， and a total input power of approximately 370 W， the lowest no-load temperature reached 5.16 K， with typical cooling capacities of 50 mW and 102 mW at 6 K and 7 K， respectively.
Heating and ventilation. Air conditioning, Low temperature engineering. Cryogenic engineering. Refrigeration
The objective of research is to develop a low-temperature system and to test a refrigeration unit with a cascade cooling system using a mixture of refrigerants R134a/R23 to provide temperatures down to –70 °C in the cooled volume. The purpose of the low-temperature system is to study the processes of refrigeration treatment and low-temperature storage of food products and materials, enzyme-endocrine raw materials, as well as climatic tests of materials, mechanical devices, and process fluids. Research was conducted at the Scientific and Educational Center Refrigeration, Cryogenic Engineering and Technology of the Federal State Budgetary Educational Institution of Higher Education Kemerovo State University. Based on the design development results, an experimental prototype of the low-temperature system was manufactured, implemented in the form of a chest with a cooled volume of 360 liters. The fundamental, design diagram, and external appearance of the cascade low-temperature system operating on a mixture of refrigerants R134a/R23 are presented. The operability and efficiency of the proposed design of the low-temperature system are proven. The ratio of mass fractions of components in the mixture of refrigerants was selected: 70 % for R134a and 30 % for R23. This ratio ensures the required cooling capacity of the low-temperature system at a refrigerant boiling point in the evaporator of –80 °C, allowing it to reach the specified temperature within a specified time interval of 3 hours at an excess refrigerant discharge pressure of less than 14 atm. The refrigeration unit has been tested. The test results are presented. The low-temperature system reaches a temperature of –70 °C within 3 hours. Moreover, the operating temperatures and pressures ensure stable operation of the unit over an extended period. The presented design solution can be used for low-temperature processing and low-temperature storage of materials at temperatures in the cooled volume down to –70 °C. It is effective for use in biotechnology and pharmaceutical production, as well as for climatic testing of various devices and materials.
The period 1980-2000 saw the impressive development of applied superconductivity in high-energy particle accelerators, from single components to long strings of superconducting magnets and high-frequency acceleration cavities. Large and powerful cryogenic systems were designed ancillary to superconducting devices operating generally close to the normal boiling point of helium, but also above 4.2 K in supercritical and below 2 K in superfluid. Low-temperature operation in accelerators also involves considerations of ultra-high vacuum, limited stored energy and beam stability. We recall the rationale for cryogenics in high-energy particle accelerators and review its development over the period of interest, with reference to the main engineering domains of cryostat design and heat loads, cooling schemes, efficient power refrigeration and cryogenic fluid management. In view of its importance and novelty, a specific section is devoted to the developments that led to the LHC at CERN.
The comparison and advantages with other engines and other aspects of Stirling engine in household appliances, to solve the problems caused by existing household appliances, realize the optimization of energy resources and achieve sustainability. A Stirling engine can work in reverse as a heat pump for heating or cooling if supplied with mechanical power. The ultra-low temperature refrigerator using the Stirling engine breaks through the traditional compressor refrigeration method in the noise, efficiency, energy consumption, stability, and other aspects of the long-term dilemma, creating a new situation of technological refrigeration. In the late 1930s, the Philips Corporation of the Netherlands successfully used the Stirling cycle in cryogenic applications. Experiments have been conducted using wind power driving a Stirling cycle heat pump for domestic heating and air conditioning. This paper mainly describes the application of the Stirling engine in household appliances and its advantages. The paper will explore the basic principle and efficiency of the Stirling engine and the use of household appliances.
In low temperature superconducting (LTS) magnets built using (cryogenic) liquid cooled superconductors, such as those designed for particle accelerators and thermonuclear fusion reactors, the operating stability and quench (sudden transition from superconducting to normal state) is a complex phenomenon. In most cases, the quenched magnet is isolated from the rest of the cryogenic system and the cryogenic fluid (helium) is expelled from the cryostat via a pressure relief valve (PRV) to prevent over-pressurization. This loss of cryogenic coolant (release to atmosphere), as well as the associated stored refrigeration results in increased operational cost (to replenish the helium), and recovery time for the LTS magnet to be operational following a quench. A novel concept for energy and cryogenic inventory management during a LTS magnet quench using direct contact (fluid mixing) heat exchange in a cryogenic buffer volume has been proposed and demonstrated. Development of a semi-analytical, one-dimensional, transient model to predict the boil-off flow generated during a quench, and the subsequent energy absorption (and pressurization) in the cryogenic buffer volume is discussed. The developed model can be used as a simplified tool for process and mechanical design of such a system.
Abstract: Refrigeration is one of the core branch in the field of thermal engineering. In other words, we can say that the refrigeration is the sister branch of the thermal engineering or thermal science. The main purpose of refrigeration is to maintain the low temperature than the atmospheric temperature or simply room temperature. In a few decades, the new trends in the field of the refrigeration and air condition has been changed drastically. The need for the development of new refrigeration processes is to achieve possible minimum temperature by the liquefaction techniques such as linde claude system. The new field known as cryogenics is developed in recent few years whose main aim is to achieve the lowest possible temperature in order of -100 to - 1500 C. the cryogenics has a wide veriety of the applications ranging from space research to the medical science which can be supposed as a science fiction in the real life. Our research work is based on the analysis of the cryogenic treatment to the lithium ion battery to improve the performance of the battery for the long period. Keywords: Cryogenics, lithium ion batteries, manganese, density, conductivity
In order to study the evolution of the size of ice crystal during its flow in horizontal straight pipes, both experiment research and numerical simulation were performed in this study. The size distribution and evolution of ice crystals for different sub-cooling degrees, flow velocities, and Ice Packing Fractions (IPF) were studied by numerical simulation using the CFD-PBM coupling model, and the numerical simulation was then verified by experiment. The results show that the distribution of ice number density could be approximately described by Gaussian distribution at the entrance of the ice slurry pipe with an IPF of 15%. With the increase in velocity and IPF, the average size of ice crystal increases along the central axis. Additionally, the size distribution of ice crystals gets more uneven along the vertical direction. With the decrease of flow velocity and the increase of IPF, the peak value of the length number density distribution of the ice crystal’s particle size increases, and the average value of the corresponding ice crystal’s particle size decreases.
Heating and ventilation. Air conditioning, Low temperature engineering. Cryogenic engineering. Refrigeration
Superconducting electronics and spectral-spatial holographic systems are being developed for advanced digital communications. These devices must operate at cryogenic temperatures of near 4 K. Liquid helium is undesirable for mobile missions due to logistics and scarcity, and commercial low temperature cryocoolers are unable to meet size, weight, power, and environmental requirements for many missions. Creare is developing a turbo-Brayton cryocooler that provides refrigeration at 4.2 K and rejects heat at 77 K to an upper-stage cryocooler or through boil-off of liquid nitrogen. The cooling system is predicted to reduce size, weight, and input power by at least an order of magnitude as compared to the current state-of-the-art 4.2 K cryocooler. For systems utilizing nitrogen boil-off, the boil-off rate is reasonable. This paper reviews the development of the cryo-compressor, a key cryocooler component. The cryo-compressor has heritage in the cryogenic circulator used in the space-borne NICMOS cryocooler. To produce the pressure ratios and mass flow rates required by the cryocooler, the cryo-compressor must operate at much higher operating speeds than the cryogenic circulator while still at cryogenic temperatures. This operating condition presents a challenge for stable operation of gas bearings at low viscosities. The approach to overcome this challenge and the testing of the compressor at cryogenic temperatures are the focus of this paper.
This paper proposes an energy consumption-prediction method for metro heating, ventilation and air-conditioning (HVAC) systems based on an auto-regressive moving average (ARMA) model using a time-series data analysis. Firstly, stationarity analysis and white-noise analysis (also known as pure stochastic analysis) were carried out on the collected energy-consumption data from actual metro HVAC systems. Secondly, optimal model parameters were determined using the autocorrelation function (ACF), and partial autocorrelation function (PACF) and Akaike information criterion (AIC). Finally, an effective energy consumption-prediction model was established. Four different methods were employed to test the effectiveness of the established ARMA model. Meanwhile, two performance indexes, namely, mean absolute error and root mean square error, were adopted to evaluate its performance in terms of fitting the observed energy consumption data. The results demonstrate that the proposed method based on the ARMA model could extract useful information from the energy data and is thus effective for energy consumption prediction of metro HVAC systems.
Heating and ventilation. Air conditioning, Low temperature engineering. Cryogenic engineering. Refrigeration
Cryogenics is the branch of science that deals with the production, behavior, and application of materials at extremely low temperatures, typically below –150°C. A cryogenic system consists of essential components such as cryocoolers, storage vessels, transfer lines, and insulation systems, all designed to maintain and control low-temperature environments efficiently. These systems play a vital role in various scientific, industrial, and medical applications. In engineering, cryogenics is used in the liquefaction and storage of gases like oxygen, nitrogen, and hydrogen. In the medical field, cryogenic techniques are employed for cryosurgery, biological sample preservation, and medical imaging technologies such as MRI. Furthermore, cryogenic systems are integral to space exploration, superconductivity research, and particle accelerators, where maintaining ultra-low temperatures is crucial for performance and stability. Advancements in materials and refrigeration technologies continue to improve efficiency and safety in cryogenic operations. This overview highlights the fundamental principles, components, and wide-ranging applications of cryogenic systems in modern science and technology.
Abstract Vuilleumier machines exhibit some attractive features such as electricity independency, ability to operate environmentally friendly and long lifetime. Moreover, they can also operate continuously with low noise, low vibrations, a variety of fuels or biofuels (or no fuel at all at solar systems), at a wide range of temperatures and with inert working gases. Apart from operating as heat pumps, with the appropriate design they can additionally produce work output. At the early years of their development, the focus of the researchers was placed on refrigeration at cryogenic temperatures. The first Vuilleumier cryogenic refrigerators were built during the 1960s for space and military applications. At the same time, theoretical models for the analysis of the performance and efficiency of the machines were developed. The refrigerators that were manufactured could provide few Watts of cooling power at a temperature range of 10–77 K. During the 1980s, the interest of utilizing the Vuilleumier cycle for cryogenic refrigerating applications reduced and the use of the cycle for residential heating and cooling increased. Many research institutions and manufacturers investigated the Vuilleumier heat pumps which in the most cases used some type of hydrocarbon gas as the source of energy. Typical values of the heating or cooling power that they could provide was 20 kW and they could reject almost 1.6 times more heat than the external combustion provided. However, their cost was higher than other available technologies at that time. The development of both Vuilleumier cryogenic refrigerators and heat pumps is an ongoing process which is aided by advanced computer design and computational softwares. Concerning the refrigerators, efforts are made to accomplish temperatures below 5 K to utilize phenomena such as the superconductivity. New materials for the regenerators are investigated. For the heat pumps, the target is to manufacture an efficient and environmentally friendly machine with competitive cost and low maintenance.
Applied superconductivity has become a key technology for high-energy particle accelerators, allowing to reach higher beam energy while containing size, capital expenditure and operating costs. Large and powerful cryogenic systems are therefore ancillary to low-temperature superconducting accelerator devices – magnets and high-frequency cavities – distributed over multi-kilometre distances and operating generally close to the normal boiling point of helium, but also above 4.2 K in supercritical and down to below 2 K in superfluid. Additionally, low-temperature operation in accelerators may also be required by considerations of ultra-high vacuum, limited stored energy and beam stability. We discuss the rationale for cryogenics in high-energy particle accelerators, review its development over the past half-century and present its outlook in future large projects, with reference to the main engineering domains of cryostat design and heat loads, cooling schemes, efficient power refrigeration and cryogenic fluid management.
A turbo expander also referred as an expansion turbine, is a centrifugal or axial flow turbine through which a high pressure gas is expanded to produce work that is often used to drive a compressor. The low pressure exhaust gas from the turbine is at a very low temperature that is 120K or less depending upon the operating conditions. It is widely used as sources of refrigeration in industrial processes and liquefaction of gases such as oxygen, nitrogen, helium, argon and krypton. A cryogenic system needs many components, compressor, heat exchanger, expansion turbine, instrumentation, vacuum vessel etc. At present most of these process plants operate at medium or low pressure due to its inherent advantages. A basic component which is essential for these processes is the turbo expander. The main aim of this project to attain a minimum temperature and pressure and to study the variation of Mach number and entropy. This is done by computational fluid flow analysis of high speed rotating turbine. This involves with the three dimensional analysis of flow through a radial expansion turbine, using nitrogen as flowing fluid. The work is performed on various modules of Ansys that is BladGen, TurboGrid, CFX-Pre, CFX-Post. Bladegen is used to create the model of turbine using available data of hub, shroud and blade profile. Turbogrid is used to mesh the model. CFX-Pre is used to define the physical parameters of the flow through the Turbo expander. CFX-Post is used for examining and analyzing results. Using these results variation of different thermodynamic properties like Temperature, Pressure, Mach number, entropy etc. inside the turbine can be seen. Several graphs are plotted showing the variation of pressure, temperature, entropy and Mach number along streamline and span wise to analyze the flow through cryogenic turbine.
Cryogenics is the branch of physics and engineering that involves the study of very low temperatures (below 123 K), how to produce them, and how materials behave at those temperatures. It is frequently applied to low temperature refrigeration applications such as in the study of physical phenomena of materials at temperature approaching absolute zero and in the liquefaction of gases. Liquefied gases such as liquid nitrogen and liquid helium are used in many cryogenic applications. Using liquid nitrogen as a refrigerant reduces chloro-fluorocarbon (CFC) emission in atmosphere and it is an eco-friendly technique. This paper deals with usage of liquid nitrogen in air conditioning of motor vehicles. First the preparation of liquid nitrogen is discussed, followed by its storage and working as a refrigerant in air conditioning system. This is followed by its advantages and draw backs.