外文翻译--制冷技术发展的历史-精品
制冷空调技术的发展与应用
制冷空调技术的发展与应用随着经济的快速发展和人民生活水平的不断提高，空调越来越成为人们生活中不可或缺的一部分。
在炎热的夏季，空调为人们带来了极大的舒适和便利，其中制冷空调技术扮演了至关重要的角色。
本文将对制冷空调技术的发展与应用进行探讨。
一、制冷空调技术的发展历程（一）初期阶段早期的制冷空调技术，最早可追溯到19世纪末20世纪初。
1902年，美国工程师Willis H. Carrier成功发明了第一台现代意义上的空调系统，为制冷空调技术的发展奠定了基础。
（二）机械式制冷空调技术的兴起机械式制冷空调技术是目前最常用的制冷技术之一，它利用压缩制冷循环对空气进行降温处理。
机械式空调的发展受到第二次世界大战的影响。
战前，空调大多用于电影院、办公室、地下商场等大型建筑场所，用于控制室内的温度和湿度。
战争期间，战斗机和轰炸机运用制冷技术避免雷达等电子设备受热影响。
（三）新型制冷剂的应用到了20世纪60年代，由于氟利昂（CFC）的广泛应用，环境问题引起人们的关注。
80年代开始，联合国和其他国际组织开展了一系列研究，证实氟利昂（CFC）是对大气臭氧层造成破坏的主要物质之一。
于是，随着环保意识的提高，制冷剂的特点开始引起重视。
制冷空调行业的改革创新也随之而来，相关行业开始积极探索新型制冷剂的应用，研制出更加环保、高效的制冷空调系统。
（四）智能化技术的运用智能化制冷空调技术以其高效、环保、节能、智能等特点广受人们青睐。
智能空调采用了先进的可控技术，使得空调可以根据室内外环境传感器、空气品质传感器、热负荷等数据自动地进行调节和优化，达到更舒适的室内环境，消耗更少的能源和环保的目的。
二、制冷空调技术的应用现状随着消费者环保意识的提高与科技创新的加速，制冷空调技术的应用范围也愈加广泛。
目前主要的应用领域如下：（一）家庭用空调目前，家用空调已形成分体、中央空调、窗式空调三种类别。
分体空调采用室内外分开设计，可以更加灵活、省空间地布局。
冷库制冷技术发展历程
冷库制冷技术发展历程冷库，作为冷链物流系统的重要组成部分，扮演着保鲜、储存和运输食品的关键角色。
而冷库制冷技术的发展历程也是一个不断创新和演进的过程。
一、初期冷库制冷技术冷库制冷技术的起源可以追溯到19世纪末，当时人们主要采用冰块或冰雪来进行食品储存。
这种方法虽然简单，但存在着存储时间短、不易控制温度等问题。
二、机械制冷技术的引入20世纪初，机械制冷技术的引入为冷库制冷技术的发展带来了革命性的变化。
人们开始使用压缩机和蒸发器等设备，通过制冷剂的循环来实现冷库的制冷效果。
这种技术使得冷库的制冷能力大幅提升，储存时间也得到了延长。
三、氨制冷技术的应用随着对环境污染和能源消耗的关注，人们开始寻求更加环保和高效的制冷技术。
氨制冷技术由此应运而生。
氨是一种无毒、无污染的制冷剂，具有良好的制冷性能和高效的制冷效果。
氨制冷技术的应用使得冷库制冷更加环保可持续，并且在大规模冷库中得到了广泛应用。
四、冷库自动控制技术随着计算机和自动控制技术的不断发展，冷库制冷技术也得到了进一步提升。
现代冷库普遍采用自动控制系统，通过传感器实时监测冷库内的温度、湿度等参数，并通过控制阀门、压缩机等设备来自动调节制冷效果。
这种技术不仅提高了冷库的稳定性和精确度，还降低了人工操作的需求。
五、新型制冷技术的应用近年来，随着科技的不断进步，新型制冷技术也逐渐应用于冷库制冷领域。
例如，吸附式制冷技术利用吸附剂吸附和释放制冷剂来实现冷库的制冷效果，具有低能耗、低噪音等优点。
另外，磁制冷技术、超导制冷技术等也在冷库制冷中得到了尝试和应用。
六、冷库能源管理技术随着能源问题的日益突出，冷库能源管理技术成为了制冷行业发展的重要方向。
通过对冷库能源消耗的监测和优化，提高制冷效率，减少能源浪费。
智能化的能源管理系统可以根据需求进行灵活调控，实现节能效果。
冷库制冷技术经历了从简单的冰块储存到机械制冷、氨制冷、自动控制等多个阶段的发展。
新型制冷技术的应用和冷库能源管理技术的发展也为冷库制冷提供了更加高效和可持续的解决方案。
外文翻译--空调与制冷技术
附录附录A 外文翻译Air Conditioning and Refrigeration TechnologyAir conditioning has rapidly grown over the past 50 years, from a luxury to a standard system includedin most residential and commercial buildings. In 1970, 36% of residences in the U.S. were either fullyair conditioned or utilized a room air conditioner for cooling (Blue, et al., 1979). By 1997, this numberhad more than doubled to 77%, and that year also marked the first time that over half (50.9%) ofresidences in the U.S. had central air conditioners (Census Bureau, 1999). An estimated 83% of all newhomes constructed in 1998 had central air conditioners (Census Bureau, 1999). Air conditioning has alsogrown rapidly in commercial buildings. From 1970 to 1995, the percentage of commercial buildings withair conditioning increased from 54 to 73%.Air conditioning in buildings is usually accomplished with the use of mechanical or heat-activatedequipment. In most applications, the air conditioner must provide both cooling and dehumidificationto maintain comfort in the building. Air conditioning systems are also used in other applications, suchas automobiles, trucks, aircraft, ships, and industrial facilities. However, the description of equipment inthis chapter is limited to those commonly used in commercial and residential buildings.Commercial buildings range from large high-rise office buildings to the corner convenience store.Because of the range in size and types of buildings in the commercial sector, there is a wide variety ofequipment applied in these buildings. For larger buildings, the air conditioning equipment is part of atotal system design that includes items such as a piping system, air distribution system, and cooling tower.Proper design of these systems requires a qualified engineer. The residential building sector is dominatedby single family homes and low-rise apartments/condominiums. The cooling equipment applied in thesebuildings comes in standard “packages” that are often both sized and installed by the air conditioningcontractor.The chapter starts with a general discussion of the vapor compressionrefrigeration cycle then movesto refrigerants and their selection. Chillers and their auxiliary systems are then covered, followed bypackaged air conditioning equipment.Even though there is a large range in sizes and variety of air conditioning systems used in buildings, mostsystems utilize the vapor compression cycle to produce the desired cooling and dehumidification. Thiscycle is also used for refrigerating and freezing foods and for automotive air conditioning. The first patenton a mechanically driven refrigeration system was issued to Jacob Perkins in 1834 inLondon, and the firstviable commercial system was produced in 1857 by James Harrison and D.E. Siebe (Thevenot 1979).Besides vapor compression, there are two less common methods used to produce cooling in buildings:the absorption cycle and evaporative cooling. These are described later in the chapter. With the vaporcompression cycle, a working fluid, which is called the refrigerant, evaporates and condenses at suitablepressures for practical equipment designs.The four basic components in every vapor compression refrigeration system are thecompressor, condenser, expansion device, and evaporator. The compressor raises the pressure of therefrigerant vapor so that the refrigerant saturation temperature is slightly above the temperature of thecooling medium used in the condenser. The type of compressor used depends on the application of thesystem. Large electric chillers typically use a centrifugal compressor while small residential equipmentuses a reciprocating or scroll compressor.The condenser is a heat exchanger used to reject heat from the refrigerant to a cooling medium. Therefrigerant enters the condenser and usually leaves as a subcooled liquid. Typical cooling mediums usedin condensers are air and water. Most residential-sized equipment uses air as the cooling medium in thecondenser, while many larger chillers use water.After leaving the condenser, the liquid refrigerant expands to a lower pressure in the expansion valve.The expansion valve can be a passive device, such as a capillary tube or short tube orifice, or an activedevice, such as a thermal expansion valve or electronic expansion valve. The purpose of the valve is toregulate the flow of refrigerant to the evaporator so that the refrigerant is superheated when it reachesthe suction of the compressor.At the exit of the expansion valve, the refrigerant is at a temperature below that of the medium (air orwater) to be cooled. The refrigerant travels through a heat exchanger called the evaporator. It absorbsenergy from the air or water circulated through the evaporator. If air is circulated through the evaporator,the system is called a direct expansion system. If water is circulated through the evaporator, it is calledachiller. In either case, the refrigerant does not make direct contact with the air or water in the evaporator.The refrigerant is converted from a low quality, two-phase fluid to a superheated vapor under normaloperating conditions in the evaporator. The vapor formed must be removed by the compressor at asufficient rate to maintain the low pressure in the evaporator and keep the cycle operating.All mechanical cooling results in the production of heat energy that must be rejected through thecondenser. In many instances, this heat energy is rejected to the environment directly to the air in thecondenser or indirectly to water where it is rejected in a cooling tower. With some applications, it ispossible to utilize this waste heat energy to provide simultaneous heating to the building. Recovery ofthis waste heat at temperatures up to 65°C (150°F) can be used to reduce costs for space heating.Capacities of air conditioning are often expressed in either tons or kilowatts (kW) of cooling. The tonis a unit of measure related to the ability of an ice plant to freeze one short ton (907 kg) of ice in 24 hr.Its value is 3.51 kW (12,000 Btu/hr). The kW of thermal cooling capacity produced by the air conditionermust not be confused with the amount of electrical power (also expressed in kW) required to producethe cooling effect.Refrigerants Use and SelectionUp until the mid-1980s, refrigerant selection was not an issue in most building air conditioning applicationsbecause there were no regulations on the use of refrigerants. Many of the refrigerants historicallyused for building air conditioning applications have been chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons(HCFCs). Most of these refrigerants are nontoxic and nonflammable. However,recent U.S. federal regulations (EPA 1993a; EPA 1993b) and international agreements (UNEP, 1987) haveplaced restrictions on the production and use of CFCs and HCFCs. Hydrofluorocarbons (HFCs) are nowbeing used in some applications where CFCs and HCFCs were used. Having an understanding ofrefrigerants can help a building owner or engineer make a more informed decision about the best choiceof refrigerants for specific applications. This section discusses the different refrigerants used in or proposedfor building air conditioning applications and the regulations affecting their use.The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) has astandard numbering system (Table 4.2.1) for identifying refrigerants (ASHRAE, 1992). Many popularCFC, HCFC, and HFC refrigerants are in the methane and ethane series of refrigerants. They are calledhalocarbons, or halogenated hydrocarbons, because of the presence of halogen elements such as fluorineorchlorine (King, 1986).Zeotropes and azeotropes are mixtures of two or more different refrigerants. A zeotropic mixture changessaturation temperatures as it evaporates (or condenses) at constant pressure. The phenomena is calledtemperature glide. At atmospheric pressure, R-407C has a boiling (bubble) point of –44°C (–47°F) and acondensation (dew) point of –37°C (–35°F), which gives it a temperature glide of 7°C (12°F). An azeotropicmixture behaves like a single component refrigerant in that the saturation temperature does not changeappreciably as it evaporates or condenses at constant pressure. R-410A has a small enough temperatureglide (less than 5.5°C, 10°F) that it is considered a near-azeotropic refrigerant mixture.ASHRAE groups refrigerants (Table 4.2.2) by their toxicity and flammability (ASHRAE, 1994).Group A1 is nonflammable and least toxic, while Group B3 is flammable and most toxic. Toxicity isbased on the upper safety limit for airborne exposure to the refrigerant. If the refrigerant is nontoxicin quantities less than 400 parts per million, it is a Class A refrigerant. If exposure to less than 400 partsper million is toxic, then the substance is given the B designation. The numerical designations referto the flammability of the refrigerant. The last column of Table 4.2.1 shows the toxicity and flammabilityrating of common refrigerants.Refrigerant 22 is an HCFC, is used in many of the same applications, and is still the refrigerant ofchoice in many reciprocating and screw chillers as well as small commercial and residential packagedequipment. It operates at a much higher pressure than either R-11 or R-12. Restrictions on the productionof HCFCs will start in 2004. In 2010, R-22 cannot be used in new air conditioning equipment. R-22cannot be produced after 2020 (EPA, 1993b).R-407C and R-410A are both mixtures of HFCs. Both are considered replacements for R-22. R-407Cis expected to be a drop-in replacement refrigerant for R-22. Its evaporating and condensing pressuresfor air conditioning applications are close to those of R-22 (Table 4.2.3). However, replacement of R-22with R-407C should be done only after consulting with the equipment manufacturer. At a minimum,the lubricant and expansion device will need to be replaced. The first residential-sized air conditioningequipment using R-410A was introduced in the U.S. in 1998. Systems using R-410A operate at approximately50% higher pressure than R-22 (Table 4.2.3); thus, R-410A cannot be used as a drop-in refrigerantfor R-22. R-410A systems utilize compressors, expansion valves, and heat exchangers designed specificallyfor use with that refrigerant.Ammonia is widely used in industrial refrigeration applications and in ammonia water absorptionchillers. It is moderately flammable and has a class B toxicity ratingbut has had limited applications incommercial buildings unless the chiller plant can be isolated from the building being cooled (Toth, 1994,Stoecker, 1994). As a refrigerant, ammonia has many desirable qualities. It has a high specific heat andhigh thermal conductivity. Its enthalpy of vaporization is typically 6 to 8 times higher than that of thecommonly used halocarbons, and it provides higher heat transfer compared to halocarbons. It can beused in both reciprocating and centrifugal compressors.Research is underway to investigate the use of natural refrigerants, such as carbon dioxide (R-744)and hydrocarbons in air conditioning and refrigeration systems (Bullock, 1997, and Kramer, 1991).Carbon dioxide operates at much higher pressures than conventional HCFCs or HFCs and requiresoperation above the critical point in typical air conditioning applications. Hydrocarbon refrigerants,often thought of as too hazardous because of flammability, can be used in conventional compressors andhave been used in industrial applications. R-290, propane, has operating pressures close to R-22 and hasbeen proposed as a replacement for R-22 (Kramer, 1991). Currently, there are no commercial systemssold in the U.S. for building operations that use either carbon dioxide or flammable refrigerants.From:Composite Index Ashrae Handbook Series空调与制冷技术过去50年以来，空调得到了快速的发展，从曾经的奢侈品发展到可应用于大多数住宅和商业建筑的比较标准的系统。
制冷英文-
制冷英文Refrigeration is an essential process for many industries and applications. It is the process of lowering the temperature of a substance or space below its ambient or initial temperature, in order to preserve, store, transport or process various products. The use of refrigeration has revolutionized the food industry, healthcare, and many other areas where temperature control is critical. In this article, we will discuss the principles and applications of refrigeration, from its history to the latest technological advances.History of RefrigerationThe history of refrigeration dates back to ancient times, when people in the Middle East and Asia stored ice in underground pits or caves, where the temperature would remain below freezing point throughout the year. This practice continued until the 18th century, when artificial refrigeration technology was developed. In 1748, William Cullen, a Scottish physician and chemist, demonstrated the principles of refrigeration by evaporating a small amount of ether in a vacuum, which caused the surrounding temperature to drop.Years later, Michael Faraday, a British scientist, also experimented with refrigeration by compressing and expanding gases. However, it was not until the late 19th century that refrigeration technology became widespread, thanks to the invention of mechanical refrigeration systems by Carl von Linde, a German engineer. His invention allowed for the production of artificial cold which spurred the development of the refrigeration systems and technologies we use today.Principles of RefrigerationThe principles of refrigeration are based on two basic thermodynamics principles, namely the first and second law of thermodynamics. The first law states that energy cannot be created or destroyed but can be converted from one form to another. The second law states that energy will always flow from a higher to a lower temperature. These two principles provide the foundation of refrigeration technology.The refrigeration cycle consists of four main components: a compressor, condenser, expansion valve and an evaporator. The compressor compresses the refrigerant gas and raises its temperature, which is then cooled in the condenser by removing heat from the refrigerant to the environment. The cooled refrigerant is then passed through the expansion valve, which reduces its pressure and causes it to evaporate in the evaporator. The heat from the substance or space being cooled is absorbed during this process, and the low-pressure gas is then sent back to the compressor to begin the cycle again.Applications of RefrigerationThere are many applications of refrigeration technology in various industries, some of which include the following:1. Food and Beverage Industry: Refrigeration is essential for preserving, storing and transporting perishable food items such as fresh fruits and vegetables, meat, dairy products and beverages. This has a direct impact on the quality, safety, and shelf life of these products.2. Healthcare Industry: Refrigeration is also vital in furnishing medical services to ensure that vaccines, drugs, and other temperature-sensitive medical supplies are transported and stored under the appropriate conditions to avoid contamination and degradation.3. Agriculture Industry: Refrigeration technology has revolutionized the agriculture industry by allowing farmers to store their produce for longer periods, ensuring that it remains fresh and in good condition until it reaches the market.4. Chemical Industry: Refrigeration is used in the chemical industry to cool raw materials, allowing them to be processed more effectively.5. Automotive Industry: Refrigeration is used to cool the engine and air conditioning systems in vehicles.Technological Advances in RefrigerationRefrigeration technology has come a long way from the early days of ice storage. The latest technological advancements in refrigeration include the following:1. Smart Refrigeration Systems: The use of advanced sensors and control systems has made it possible to monitor and adjust the temperature and humidity of refrigerated spaces to ensure optimal conditions.2. Alternative Refrigerants: Due to the environmental impacts of traditional refrigerants, new alternative refrigerants such as carbon dioxide, ammonia and hydrocarbons are being developed.3. Magnetic Refrigeration: This technology uses magnetic fields to cool substances, which is more energy-efficient and environmentally friendly than traditional refrigeration.4. Cryogenic Refrigeration: This technology is used to cool substances to extremely low temperatures using liquid nitrogen or other cryogens.ConclusionRefrigeration is an essential process that has revolutionized various industries and applications. From the early days of ice storage to the latest technological advancements, refrigeration technology has come a long way. With the development of smart refrigeration systems, alternative refrigerants, magnetic refrigeration and cryogenic refrigeration, refrigeration technology is poised for even greater advances and applications, which will have a significant impact on industries and society as a whole.。
制冷技术(英文版)Ch2-090528
Part 2. The Principles of Refrigeration ( 116 pages)Chapter 2. Thermodynamic Analysis of refrigeration cycle2-1) The Laws of Thermodynamics and Their Relation to RefrigerationThermodynamics are primarily concerned with two forms of energy: heat and work. Therefore Engineering Thermodynamics is the study of the interrelation between heat, work, and internalenergy.There are two important concepts of thermodynamic analysis: System and Environment.A system（系统、体系）is defined as any quantity of matter or region of space to which attentionis directed for purpose of analysis;and everything outside the system boundary is referred to as the environment（环境）.[1,2] （1）The 0th Law of ThermodynamicsThe Zeroth Law of Thermodynamics states: 热平衡定律—温度定义1.If two systems are each equal in temperature to a third system, then the temperatures of the twosystems themselves are equal.2.If two closed systems (together isolated), with different temperatures are brought into thermalcontact, then the temperatures of the two systems will change to approach the same temperature.That is, the temperature of the system which is at a higher temperature will decrease and thetemperature of the system with the lower temperature will increase. They will eventually have the same temperature.热力学第零定律的重要性在于它给出了温度的定义和温度的测量方法。
制冷原理(中英文对照)
制冷原理培训教材Refrigeration principletraining material一：制冷原理简介Refrigeration principle本系统属于蒸汽压缩式制冷循环,主要包括压缩机、冷凝器、毛细管、干燥过滤器、蒸发器5个部件，经过压缩、冷凝、节流、蒸发四个过程不断循环,制冷剂周期性的发生从蒸汽变为液体，从液体变为蒸汽的状态变化，不端的把冰箱内的热量转移到冰箱外部，从而达到制冷目的。
The appliance incorporates a vapor compressor refrigeration system that consists of compressor，condenser, capillary, filter drier and evaporator and accomplishes the refrigeration through the cycle of compression, condensation, throttling, and evaporation. The process repeats and extracts the heat from the fridge compartment by having the refrigerant evaporated in the evaporator and liquefied in the condenser。
二：主关件简介：Main components（一)：压缩机Compressor制冷系统的“心脏”,起压缩和输送制冷剂的作用，目前所用为往复活塞式压缩机.Serving as the heart of the refrigeration system，the compressor functions through compressing and passing the refrigerant. A reciprocal compressor is adopted in the system。
制冷技术的发展历史
制冷技术的发展历史嘿，咱今儿就来聊聊制冷技术的发展历史。
你想想啊，在很久以前，那时候可没有冰箱空调这些玩意儿。
夏天热得要命，人们只能用扇子扇扇风，或者找个阴凉地儿躲躲。
要是有个大冰块儿，那可就跟宝贝似的。
最早的制冷方法，那真的是超级原始呢！就跟咱小时候玩的土办法似的。
据说有人会用硝石溶于水来吸热制冷，这可真是够有创意的呀！后来呢，慢慢地有了一些更厉害的发明。
就像蒸汽机的出现，那可给制冷技术带来了新的突破。
这就好比给制冷技术这匹小马套上了更有力的缰绳，让它能跑得更快更远啦。
再到后来，压缩式制冷机出现啦！这可真是个大宝贝呀！它就像一个超级英雄，拯救了我们在夏天被热得死去活来的命运。
有了它，我们可以随时享受到清凉的感觉，食物也能更好地保存啦。
哎呀，你说这制冷技术的发展是不是特别神奇？从一开始的简单尝试，到后来越来越先进，越来越好用。
这就好像一个小孩子慢慢长大，变得越来越厉害。
而且啊，制冷技术可不只是给我们带来了凉快和食物的保鲜这么简单哦。
你想想看，医院里的很多药品、疫苗都需要低温保存，要是没有制冷技术，那得有多少人得不到及时的治疗呀！还有那些科研实验，很多都需要在特定的温度下进行，没有制冷技术的支持，那很多科研成果可能都出不来呢！现在的制冷技术啊，那真的是五花八门，各式各样。
有家用的冰箱、空调，还有大型的冷库、冷藏车。
这就像是一个庞大的制冷家族，每个成员都有自己独特的本领和用处。
咱再想想未来，制冷技术肯定还会有更大的发展。
说不定以后的冰箱可以自己识别食物，自动调节温度呢！或者空调可以根据人的体温和心情来调整温度和风速，哇，那可真是太酷啦！总之啊，制冷技术的发展历史就是一部人类追求舒适和便利的历史。
它让我们的生活变得更加美好，更加丰富多彩。
咱可得好好感谢那些为制冷技术发展做出贡献的人们呀！就这么着吧！。
冷冻技术的历史 雅思
冷冻技术的历史雅思The history of freezing technology dates back to ancient times when people used natural ice and snow to preserve food. However, the development of modern freezing techniques has revolutionized the food industry, medicine, and various other fields. The process of freezing involves lowering the temperature of a substance to below its freezing point, thereby preserving it by inhibiting the growth of microorganisms and slowing down chemical reactions. This essay will delve into the historical evolution of freezing technology, its impact on society, and the future potential of this innovation.Freezing as a method of food preservation has been practiced for centuries. In ancient civilizations, people stored food in ice caves or used snow and ice to keep food fresh. However, the invention of the first artificial refrigeration system in the 19th century marked a significant milestone in the history of freezing technology. This breakthrough allowed for the mass production and distribution of frozen food, transforming the way people consumed and preserved food. The ability to freeze food on an industrial scale not only extended theshelf life of perishable items but also enabled the transportation of food over long distances, reducing food waste and ensuring a more stable food supply.The impact of freezing technology extends beyond the realm of food preservation. In the field of medicine, freezing techniques such as cryotherapy have been utilized for various purposes, including the removal of abnormal tissue, treatment of skin conditions, and preservation of biological samples. The ability to freeze and store biological materials has revolutionized medical research and organ transplantation, as it allows for the long-term preservation of tissues and organs, thereby saving countless lives.Moreover, freezing technology has also played a crucial role in the development of the aerospace industry. The ability to preserve and store food for extended periods has been essential for space missions, enabling astronauts to have access to nutritious meals during their journeys. Furthermore, freezingtechnology has been instrumental in the storage and transportation of sensitive materials such as pharmaceuticals, chemicals, and electronics, ensuring their integrity and quality.Looking ahead, the future potential of freezing technology is vast. With ongoing advancements in cryopreservation, there is growing interest in the possibility of preserving whole organisms, including humans, at ultra-low temperatures for potential revival in the future. While this concept remains highly speculative, it raises profound ethical and philosophical questions about the nature of life and the boundaries of medical science.In conclusion, the history of freezing technology is a testament to human ingenuity and innovation. From its humble origins in ancient times to its widespread applications in the modern world, freezing technology has had a profound impact on society, revolutionizing the way we preserve food, conduct medical procedures, and explore outer space. As we continue to unlock the potential of freezing technology, it is essential to consider the ethical implications and ensure that its benefits are harnessed for the betterment of humanity.。
制冷技术的研究与发展前景
制冷技术的研究与发展前景制冷技术是现代工业、商业、家庭不可或缺的一部分，其应用涉及到诸多领域，如食品、医药制品、电子、建筑等。
为了满足不断增长的市场需求，制冷技术不断发展，向着更加智能、高效和环保的方向进行着探索。
一、制冷技术发展的历程制冷技术的历程可以追溯到古代。
古文献中对冷藏食品和水进行防腐的方法也很常见，一般是通过使用大量的冰块或者是将物品暴露在凉爽的地下室中进行保鲜。
不过，这些方法都具备一定的缺陷，无法稳定地保持低温状态。
制冷技术的大规模应用始于19世纪。
当时，西方国家的工业化和城市化迅猛发展，对制冷技术的需求急剧增加。
在这种情况下，人们开始寻求更为先进和高效的制冷方法。
最早的制冷设备采用的是蒸发制冷，即将液态氨或二氧化硫注入一个密闭的容器中，让其蒸发并吸收热量，以达到制冷的效果。
然而，这种方法存在安全隐患，经常发生泄漏爆炸事故。
20世纪后期，制冷技术取得了重大的进展。
一方面，新型的制冷剂开始广泛应用。
目前，最为常见的制冷剂是氟里昂和氨冷剂。
这些制冷剂不仅效果更好，而且更加安全环保。
另一方面，制冷设备的技术也得到了极大的提升，比如，涡旋冷却器、喷射冷却器等都是现代制冷设备的代表。
二、制冷技术发展的机遇与挑战当前，全球对制冷设备的需求正在不断提高。
一方面，气候的变化导致室内温度不断上升，为了确保舒适的生活环境，人们需要更加高效的空调设备。
另一方面，冷链物流的需求正在逐年增长，而如何保证物品在运输途中的质量安全也是制冷技术急需解决的问题。
同时，制冷技术的发展也面临着一些挑战。
一方面，不断变化的环保法规不断增加制冷设备的研发和生产成本。
另一方面，现有的制冷剂存在着对臭氧层和全球气候的影响。
如何选择、研发、使用更加环保的制冷剂成了制冷技术领域的重要课题。
三、制冷技术的发展趋势随着技术不断进步，新型的制冷设备和制冷剂正在逐步取代传统的设备和制冷剂。
例如，使用磁制冷技术的制冷设备，其工作原理是通过改变磁场的方式来实现制冷。
译文_secret
英国制冷协会1998-1999年的总结文摘建筑体系设计大学南岸大学伦敦103号街建筑环境大学诺丁汉大学英国大学公寓诺丁汉2路1999年10月25日收到摘要这篇文章是1998年10月到1999年4月英国制冷协会提供的7篇技术论文的精要概括.这篇文章的目的是为英国制冷协会的研究与发展指明更广阔的道路.它的主题包括空气调节在内的空气循环，液体压力的放大，大面积沸腾制冷剂的用运和冷冻食品最佳条件下保存的经验.。
它也包括了热力学制冷在最近的发展状况,为细胞提供制冷的可能性.这些出版物还包括了一篇由专家提出的关于提高制冷剂效率的最新研究..关键词: 制冷工业空气调节科研成果展示相关权威电话: +44-207-8157676 传真：+44-207-8157699名词术语：V/Ud2—————不扩散流动系数V ——————流入压缩机入口的流量单位: M3/SU ——————压缩机的最高速度单位:M/Sd ——————汽缸的直径单位:M1: 前言为了发展制冷科学,英国制冷协会在1899年成立.。
从那时开始,它有了一定的发展，并且做出了在最新最前沿的制冷领域有重要影响的技术论文.这些文章由协会的领导,专家,还有一些英国制冷工业的人士所写的。
.对协会作过贡献的将近有3000多个成员(他们大部分现在还健在)。
这篇文章的目的是将协会的巨大研究推到更为广阔的制冷协会的应用。
它的主题包括空气调节的空气循环，液体压力的放大，大面积沸腾制冷剂的用运和冷冻食品最佳条件下保存的经验.它也包括了热力学制冷在最近的发展状况,为细胞提供制冷的可能性.这些出版物还包括了一偏由专家提出的关于提高制冷剂效率的最新研究。
2: 过程回顾2.1 液体压力的放大MacWhirter的报告提到把液体压力放大的放大系数用运到制冷系统.专家在液体流程中把封闭式通过泵来输送制冷剂作为连续蒸汽压缩系统的例子来描述液体压力放大系统,如图—1所示。
加压泵把管道中的压力升到相当于1到1。
制冷方面英文文献翻译
应用热工程摘要:紧凑型翅片管蒸发器已被广泛应用于轻型商用制冷盒应用，这样的制冷系统空间的约束，因此，热交换器（冷凝器和蒸发器）必须有大面积体积比。
此外，这样的应用程序需要一个诱导在翅片表面的霜层的生长的冰点以下的蒸发温度，如果不使用适当的除霜策略，可能会阻止蒸发器除霜。
彻底阻止蒸发器之前，霜层消耗热交换器的性能，通过增加一个额外的热阻和也由减少空气流量风机。
彻底阻挡蒸发器之前，可以通过增加一个额外的热阻或者增加一个减少空气流量风机可以减少霜层消耗热交换器的性能。
了解这些紧凑的热霜冻形成的途径换热器和风扇由霜堵塞影响的鲁棒设计方法是强制性的制冷系统以及设计更高效的除霜方法。
在这项研究中的实验对翅片管蒸发器风扇特性考虑霜积进行了调查。
为此，专门设计，建造和校准风洞设施进行闭环。
实验测试了四种不同的执行（三波纹翅片和百叶窗翅片）蒸发器在不同的条件下，线圈。
发现结霜速率随空气流量，过冷度和散热片的密度。
霜冻积累的质量之间的相关关系，空气侧压降和冷却能力也被观察到。
也有人指出，风机特性发挥在蒸发器的热性能的重要作用，表明结霜工况下的风扇蒸发器对设计必须作为一个耦合系统。
此外，对于相同的操作条件下，该百叶窗翅片蒸发器均要比波浪翅片盘管结霜的影响更敏感。
2010爱思唯尔公司保留所有权利。
1、介绍能源资源的使用效率是现代社会中的基本问题，不仅是由于其内在环境的吸引力，而且稳步增长的成本，鼓励的方式产生能量的变化，分配和消费。
由于制冷部门负责全球消耗大量的能量，多数政府开展能源消费政策，以刺激高效制冷系统的发展。
然而，开发的这样一类的制冷机组不仅依赖于系统的组件设计（例如，高效率的压缩机，防污冷凝器，无霜蒸发器），而且它们之间的一个适当的匹配。
中背压（MBP）轻型商用制冷设备通常运行蒸发温度接近10℃时，蒸发器盘管上的霜层的温度，有利于形成。
由于换热器的性能的导热系数低，结霜层和减少风扇提供的空气流率的综合效果，累计蒸发器盘管上的霜会显着下降。
雅思阅读history of refrigeration
雅思阅读history of refrigeration摘要：I.引言- 介绍制冷技术的发展历程II.古代制冷技术- 冰窖和井水的使用- 利用动植物材料进行制冷III.工业化早期的制冷技术- 各种制冷机器的发明与改进- 制冷剂的发展与应用IV.现代制冷技术的普及- 电冰箱和空调的发明与发展- 制冷技术在日常生活中的应用V.制冷技术对人类生活的影响- 食品保存与公共卫生- 舒适生活环境的改善VI.制冷技术的可持续性发展- 制冷技术对环境的影响- 绿色制冷技术的应用与展望正文：制冷技术的发展历程可以说是人类科技进步的缩影，从古至今，人们一直在寻找各种方法来降低温度，以延长食品的保质期和创造舒适的生活环境。
在古代，人们主要依靠冰窖和井水来降低环境温度。
冰窖是一种利用地下空间储存冰块的方法，冰块的融化可以降低窖内温度。
而井水则因其较地下水温度低而成为人们消暑的良方。
此外，人们还发现动植物材料如树皮、草和棉花等具有吸热性能，可用于降低环境温度。
工业化早期，各种制冷机器的发明与改进推动了制冷技术的发展。
18 世纪，苏格兰工程师威廉·卡伦发明了第一台制冷机器，该机器使用氨和水的混合物作为制冷剂。
19 世纪，美国发明家托马斯·萨维里和英国发明家詹姆斯·杜蒙特分别发明了电冰箱的原型。
制冷剂的发展也取得了突破，例如，1895 年，查尔斯·米特兰德发明了第一个氟利昂制冷循环系统。
20 世纪以后，现代制冷技术逐渐普及。
家用电冰箱和空调的发明与发展使得制冷技术走进了千家万户。
制冷技术在日常生活中的应用不仅体现在食品保存和防暑降温上，还体现在医药、化工、建筑等多个领域。
然而，制冷技术的发展也给环境带来了挑战。
制冷剂的使用导致臭氧层破坏和全球气候变暖。
为了应对这一挑战，人们开始研究和推广绿色制冷技术，例如，使用天然制冷剂和太阳能制冷等。
总之，制冷技术的发展为人类带来了诸多便利，但也带来了环境问题。
制冷技术的
FOREWORDThe practice of refrigeration undoubtedly goes back as far as the history of mankind, but for thousands of years the only cooling mediums were water and ice. Today refrigeration in the home, in the supermarket, and in commercial and industrial usage is so closely woven into our everyday existence it is difficult to imagine life without it. But because of this rapid growth, countless people who must use and work with refrigeration equipment do not fully understand the basic fundamentals of refrigeration system operation.This manual is designed to fill a need which exists for a concise, elementary text to aid servicemen, salesman, students, and others interested in refrigeration. It is intended to cover only the fundamentals of refrigeration theory and practice. Detailed information as to specific products is available from manufacturers of complete units and accessories. Used to supplement such literature—and to improve general knowledge of refrigeration—this manual should prove to be very helpful.© 1968 Emerson Climate Technologies, Inc.All rights reserved.Section 1 Basic Refrigeration PrinciplesThermodynamics 1-1 Heat 1-1 Temperature 1-1 Heat Measurement 1-2 Heat Transfer 1-2 Change of State 1-3 Sensible Heat 1-3 Latent Heat of Fusion 1-3 Latent Heat of Evaporation 1-4 Latent Heat of Sublimation 1-4 Saturation Temperature 1-4 Superheated Vapor 1-4 Subcooled Liquid 1-4 Atmospheric Pressure 1-4 Absolute Pressure 1-5 Gauge Pressure 1-5 Pressure-Temperature Relationships, Liquids 1-5 Pressure-Temperature Relationships, Gases 1-5 Specific Volume 1-6 Density 1-6 Pressure and Fluid Head 1-6 Fluid Flow 1-7 Effect of Fluid Flow on Heat Transfer 1-7Section 2 RefrigerantsTerminology and Examples 2-1 Pure Fluid 2-1 Mixture and Blend 2-1 Azeotropic Refrigerant Mixture 2-1 Zeotropic Mixture 2-2 Near-Azeotropic Refrigerant Mixture 2-2 How are Components Chosen 2-2 Mixture Behavior 2-3 Azeotrope 2-3 Zeotrope 2-3 Near-Azeotropic Refrigerant Mixtures 2-3 What Happens to Mixture Composition During System Charging? 2-3 Temperature Glide 2-4 What Happens to Refrigerant MixtureComposition During a Leak? 2-5Types of Refrigerant 2-5 Refrigerants 2-8 Refrigerant 12 2-8 Refrigerant R-401A/B 2-8 Refrigerant R-409A 2-8 Refrigerant 134a 2-8 Refrigerant 22 2-9 Refrigerant R-502 2-9 Refrigerant R-402A 2-9 Refrigerant R-408A 2-9 Refrigerant R-404A 2-9 Refrigerant R-507 2-10 Refrigerant Saturation Temperature 2-10 Refrigerant Evaporation 2-10 Refrigerant Condensation 2-10 Refrigerant-Oil Relationships 2-10 Refrigerant Tables 2-11 Saturation Properties 2-12 Pocket Temperature-Pressure Charts 2-12 Section 3 The Refrigeration CycleSimple Compression Refrigeration Cycle 3-1 Heat of Compression 3-2 Volumetric Efficiency of the ReciprocatingCompressor 3-2 Volumetric Efficiency of the Scroll Compressors 3-4 Effect of Change in Suction Pressure 3-4 Effect of Change in Discharge Pressure 3-4 Effect of Subcooling Liquid Refrigerant with Water or Air 3-4 Effect of Subcooling Liquid Refrigerant bySuperheating the Vapor 3-4 Effect of Superheating the Vapor Leavingthe Evaporator 3-5 Effect of Pressure Drop in the Discharge Line and Condenser 3-5 Effect of Pressure Drop in Liquid Line 3-5 Effect of Pressure Drop in the Evaporator 3-5 Effect of Pressure Drop in Suction Line 3-6 Internally Compound Two-Stage Systems 3-6 Externally Compound Systems 3-6 Cascade Systems 3-10Table of Contents© 1968 Emerson Climate Technologies, Inc.All rights reserved.© 1968 Emerson Climate Technologies, Inc.All rights reserved.Most users of refrigeration products normally associate refrigeration or air conditioning with cold and cooling, yet the practice of refrigeration engineering deals almost entirely with the transfer of heat. This seeming contradic-tion is one of the most fundamental concepts that must be grasped to understand the workings of a refrigeration or air conditioning system. Cold is really only the ab-sence of heat, just as darkness is the absence of light, and dryness is the absence of moisture.THERMODYNAMICSThermodynamics is that branch of science dealing with the mechanical action of heat. There are certain fundamental principles of nature, often called laws of thermodynamics, which govern our existence here on Earth. Several of these laws are basic to the study of refrigeration.The first and most important of these laws is the fact that energy can neither be created or destroyed. It can only be converted from one type to another. A study of thermodynamic theory is beyond the scope of this manual, but the examples that follow will illustrate the practical application of the energy law.HEATHeat is a form of energy, primarily created by the trans-formation of other types of energy into heat energy. For example, mechanical energy turning a wheel causes friction and is transformed into heat energy. When a vapor such as air or refrigerant is compressed, the compression process is transformed into heat energy and heat is added to the air or refrigerant.Heat is often defined as energy in motion, for it is never content to stand still. It is always moving from a warm body to a colder body. Much of the heat on the Earth is derived from radiation from the sun. The heat is being transferred from the hot sun to the colder earth. A spoon in ice water loses its heat to the water and becomes cold. Heat is transferred from the hot spoon to the colder ice water. A spoon in hot coffee absorbs heat from the coffee and becomes warm. The hot coffee transfers heat to the colder spoon. The terms warmer and colder are only comparative. Heat exists at any temperature above absolute zero even though it may be in extremely small quantities.Absolute zero is the term used by scientists to de-scribe the lowest theoretical temperature possible, the temperature at which no heat exists. This occurs at approximately 460° below zero Fahrenheit, 273° belowSection 1BASIC REFRIGERATION PRINCIPLESzero Celsius. By comparison with this standard, the coldest weather we might ever experience on Earth is much warmer.TEMPERATURETemperature is the scale used to measure the intensity of heat, the indicator that determines which way the heat energy will move. In the United States, tempera -ture is normally measured in degrees Fahrenheit. The Celsius scale (previously termed Centigrade) is widely used in most other parts of the world. Both scales have several basic points in common, (See Figure 1-1) the freezing point of water, and the boiling point of water at sea level. At sea level, water freezes at 32°F (0°C) and water boils at 212°F (100°C). On the Fahrenheit scale, the temperature difference between these two points is divided into 180 equal increments or degrees F, while on the Celsius scale the temperature difference is divided into 100 equal increments or degrees C. The relation between Fahrenheit and Celsius scales can always be established by the following formulas:Fahrenheit = 9/5 Celsius + 32°Celsius = 5/9 (Fahrenheit -32°)Figure 1-1Further observing the two scales, note that at -40°, both the Fahrenheit and Celsius thermometers are at the same point. This is the only point where the two scales are identical. Using this information, the follow -ing formulas can be used to determine the equivalent Fahrenheit or Celsius values.Fahrenheit = ((Celsius + 40) x 9/5) - 40Celsius = ((Fahrenheit + 40) x 5/9) - 401-1© 1968 Emerson Climate Technologies, Inc.All rights reserved.HEAT MEASUREMENTThe measurement of temperature has no relation to the quantity of heat. A match flame may have the same temperature as a bonfire, but obviously the quantity of heat given off is vastly different.The basic unit of heat measurement used today in the United States is the British Thermal Unit, commonly expressed as a BTU. A BTU is defined as the amount of heat added or removed to change one pound of wa-ter one degree Fahrenheit. For example, to raise the temperature of one gallon of water (approximately 8.3 pounds) from 70°F to 80°F will require 83 BTUs.1 gallon (8.3 pounds) x (80°F - 70°F)∆T = 83 BTUsheat added8.3 pounds x 10°∆T = 83 BTUsIn the metric system, the basic unit of heat measure-ment is the Calorie. A Calorie is defined as the amount of heat added or removed to change one gram of water one degree Celsius. For example, to lower one liter of water (1000 grams) from 30°C to 20°C will require 10,000 Calories of heat to be removed.1000 grams X (30°C - 20°C)∆T = 10,000 Calories ofheat removed.HEAT TRANSFERThe second important law of thermodynamics is that heat always travels from a warm object to a colder one. The rate of heat travel is in direct proportion to the temperature difference between the two bodies.390°F400°FHeat FlowFigure 1-2Assume that two steel balls are side by side in a perfectly insulated box. One ball weighs one pound and has a temperature of 400°F, while the second ball weighs 1,000 pounds and has a temperature of 390°F. The heat content of the larger ball is much greater than the small one, but because of the temperature difference, heat will travel from the small ball to the large one (See Figure 1-2) until the temperatures equalize. Heat cantravel in any of three ways; radiation, conduction, or convection.Radiation is the transfer of heat by waves similar to light waves or radio waves. For example, the sun's energyis transferred to the Earth by radiation.One need only step from the shade into direct sunlight to feel the impact of the heat waves even though the temperature of the surrounding air is identical in both places. Another example of radiation is standing in front of a bonfire. The side of you facing the bon fire is receiving radiant heat and that side is hot. The side away from the fire may feel cool. There is little radiation at low temperatures and at small temperature differ-ences. As a result, radiation is of little importance in the actual refrigeration process. However, radiation to the refrigerated space or product from the outside environ-ment, particularly the sun, may be a major factor in the refrigeration load.Conduction is the flow of heat through a substance. Actual physical contact is required for heat transfer to take place between two bodies by this means. Conduc-tion is a highly efficient means of heat transfer as any serviceman who has touched a piece of hot metal cantestify.HOT WARM COOLFigure 1-41-2© 1968 Emerson Climate Technologies, Inc.All rights reserved.Figure 1-4 shows a flame heating one end of a metal rod. Heat is conducted to the other end by the process of conduction.Convection is the flow of heat by means of a fluid me -dium, either vapor or liquid, normally air or water. Air may be heated by a furnace, and then discharged intoa room to heat objects in the room by convection.Figure 1-5In a typical air conditioning/refrigeration application, heat normally will travel by a combination of processes. The ability of a piece of equipment to transfer heat is referred to as the overall rate of heat transfer. While heat transfer cannot take place without a temperature difference, different materials vary in their ability to conduct heat. Metal is a very good heat conductor. Fiberglass has a lot of resistance to heat flow and is used as insulation.CHANGE OF STATEMost common substances can exist as a solid, a liquid, or a vapor, depending on their temperature and the pressure to which they are exposed. Heat can change their temperature, and can also change their state. Heat is absorbed even though no temperature change takes place when a solid changes to a liquid, or when a liquid changes to a vapor. The same amount of heat is given off, rejected, even though there is no temperature change when the vapor changes back to a liquid, and when the liquid is changed back to a solid.The most common example of this process is water. It generally exists as a liquid, but can exist in solid form as ice, and as a vapor when it becomes steam. As ice it is a usable form for refrigeration, absorbing heat as it melts at a constant temperature of 32°F (0°C). As water, when placed on a hot stove in an open pan, its temperature will rise to the boiling point, 212°F (100°C) at sea level. Regardless of the amount of heat applied, the waters temperature cannot be raised above 212°F (100°C) because the water will vaporize into steam. Ifthis steam could be enclosed in a container and more heat applied, then the water vapor, steam, temperature could again be raised. Obviously the fluid during the boiling or evaporating process was absorbing heat.When steam condenses back into water it gives off ex-actly the same amount of heat that it absorbed during evaporation. (The steam radiator is a common usage of this source of heat.) If the water is to be frozen into ice, the same amount of heat that was absorbed in melting must be extracted by some refrigeration process to cause the freezing action.The question arises, just where did those heat units go? Scientists have found that all matter is made up of mol-ecules, infinitesimally small building blocks which are ar -ranged in certain patterns to form different substances. In a solid or liquid, the molecules are very close together. In a vapor the molecules are much farther apart and move about much more freely. The heat energy that was absorbed by the water became molecular energy, and as a result the molecules rearranged themselves, changing the ice into water, and the water into steam. When the steam condenses back into water, that same molecular energy is again converted into heat energy.SENSIBLE HEATSensible heat is defined as the heat involved in a change of temperature of a substance. When the temperature of water is raised from 32°F to 212°F, an increase in sensible heat content is taking place. The BTUs required to raise the temperature of one pound of a substance 1°F is termed its specific heat. By definition, the specific heat of water is 1.0 BTU/lb. The amount of heat required to raise the temperature of different substances through a given temperature range will vary. It requires only .64 BTU to raise the temperature of one pound of butter 1°F, and only .22 BTU is required to raise the temperature of one pound of aluminum 1°F . Therefore the specific heats of these two substances are .64 BTU/lb. and .22 BTU/lb. respectively. To raise the temperature of one pound of liquid refrigerant R-22, 1°F from 45° to 46°, requires .29 BTUs, therefore its specific heat is .29 BTU/TENT HEAT OF FUSIONA change of state for a substance from a solid to a liquid, or from a liquid to a solid involves the latent heat of fu-sion. It might also be termed the latent heat of melting, or the latent heat of freezing.When one pound of ice melts, it absorbs 144 BTUs at a constant temperature of 32°F. If one pound of water is to be frozen into ice, 144 BTUs must be removed from the water at a constant temperature of 32°F. In the freezing of food products, it is only the water content1-3© 1968 Emerson Climate Technologies, Inc.All rights reserved.for which the latent heat of freezing must be taken into account. Normally this is calculated by determining the percentage of water content in a given TENT HEAT OF EVAPORATIONA change of a substance from a liquid to a vapor, or from a vapor back to a liquid involves the latent heat of evaporation. Since boiling is only a rapid evaporating process, it might also be called the latent heat of boil-ing, the latent heat of vaporization, or for the reverse process, the latent heat of condensation.When one pound of water boils or evaporates, it absorbs 970 BTUs at a constant temperature of 212°F (at sea level). To condense one pound of steam to water, 970 BTUs must be extracted from the steam.Because of the large amount of latent heat involved in evaporation and condensation, heat transfer can be very efficient during the process. The same changes of state affecting water applies to any liquid, although at different temperatures and pressures.The absorption of heat by changing a liquid to a vapor, and the discharge of that heat by condensing the vapor is the keystone to the whole mechanical refrigeration process. The movement of the latent heat involved is the basic means of refrigeration.When one pound of refrigerant R-22 boils, evaporates, it absorbs 85.9 BTUs at 76 psig. To condense one pound of R-22, 85.9 BTUs must be extracted from the refrigerant vapor.LATENT HEAT OF SUBLIMATIONA change in state directly from a solid to a vapor without going through the liquid phase can occur with some substances. The most common example is the use of "dry ice" or solid carbon dioxide when used for cooling. The same process can occur with ice below the freez-ing point. This process is utilized in some freeze-drying processes at extremely low temperatures and deep vacuums. The latent heat of sublimation is equal to the sum of the latent heat of fusion and the latent heat of evaporation.SATURATION TEMPERATUREThe condition of temperature and pressure at which both liquid and vapor can exist simultaneously is termed saturation . A saturated liquid or vapor is one at its boiling point. For water at sea level, the saturation temperature is 212°F . At higher pressures, the saturation temperature increases. With a decrease in pressure, the saturation temperature decreases.The same condition exists for refrigerants. At the refrig-erants boiling point, both liquid and vapor exist simul-taneously. For example, refrigerant R-22 has a boiling point of 45°F at a pressure of 76 psig. It's boiling point changes only as it pressure changes.SUPERHEATED VAPORAfter a liquid has changed to a vapor, any further heat added to the vapor raises its temperature. As long as the pressure to which it is exposed remains constant, the resulting vapor is said to be superheated. Since a temperature rise results, sensible heat has been added to the vapor. The term superheated vapor is used to describe a vapor whose temperature is above it's boil-ing or saturation point. The air around us is composed of superheated vapor.Refrigerant 22 at 76 psig has a boiling point of 45°F. At 76 psig, if the refrigerants temperature is above 45°F, it is said to be superheated.SUBCOOLED LIQUIDAny liquid that has a temperature lower than the satura-tion temperature corresponding to its saturation pres-sure is said to be subcooled. Water at any temperature less than its boiling temperature (212°F at sea level) is subcooled.The boiling point of Refrigerant 22 is 45°F at 76 psig. If the actual temperature of the refrigerant is below 45°F at 76 psig, it is said to be subcooled.ATMOSPHERIC PRESSUREThe atmosphere surrounding the Earth is composed of gases, primarily oxygen and nitrogen, extending many miles above the surface of the Earth. The weight of that atmosphere pressing down on the Earth creates the atmospheric pressure in which we live. At a given point, the atmospheric pressure is relatively constant except for minor changes due to changing weather conditions. For purposes of standardization and as a basic reference for comparison, the atmospheric pres-sure at sea level has been universally accepted. It has been established at 14.7 pounds per square inch, (psi). This is equivalent to the pressure exerted by a column of mercury 29.92 inches high.At altitudes above sea level, the depth of the atmo-spheric blanket surrounding the Earth is less, therefore the atmospheric pressure is less. At 5,000 feet eleva-tion, the atmospheric pressure is only 12.2 psi., 28.84 inches of mercury.1-4© 1968 Emerson Climate Technologies, Inc. All rights reserved.unit of measurement since even inches of mercury is too large for accurate reading. The micron, a metric unit of length, is used for this purpose. When we speak of microns in evacuation, we are referring to absolute pressure in units of microns of mercury.A micron is equal to 1/1000 of a millimeter and there are 25.4 millimeters per inch. One micron, therefore, equals 1/25,400 inch. Evacuation to 500 microns would be evacuating to an absolute pressure of approximately .02 inch of mercury. At standard conditions this is the equivalent of a vacuum reading of 29.90 inches mer-cury.PRESSURE-TEMPERATURE RELATIONSHIPS, LIQUIDSThe temperature at which a liquid boils is dependent on the pressure being exerted on it. The vapor pressure of the liquid is the pressure being exerted by the tiny molecules seeking to escape the liquid and become vapor. Vapor pressure increases with an increase in temperature until at the point when the vapor pressure equals the external pressure, boiling occurs.Water at sea level boils at 212°F, but at 5,000 feet eleva-tion it boils at 203°F due to the decreased atmospheric pressure. (See Table 1-1) If some means, a compressor for example, is used to vary the pressure on the sur-face of the water in a closed container, the boiling point can be changed at will. At 100 psig, the boiling point is 337.9°F, and at 1 psig, the boiling point is 215.3°F. Since all liquids react in the same fashion, although at different temperatures and pressure, pressure provides a means of regulating a refrigerant's temperature. The evaporator is a part of a closed system. A pressure can be maintained in the coil equivalent to the saturation temperature (boiling point) of the liquid at the cooling temperature desired. The liquid will boil at that tempera-ture as long as it is absorbing heat and the pressure does not change.In a system using refrigerant R-22, if the pressure within the evaporator coil is maintained at 76 psig, the refrigerants boiling point will be 45°F (7.2°C). As long as the temperature surrounding the coil is higher than 45°F (7.2°C), the refrigerant will continue to boil absorbing heat.PRESSURE-TEMPERATURE RELATIONSHIPS, GASESOne of the basic fundamentals of thermodynamics is the "perfect gas law." This describes the relationship of the three basic factors controlling the behavior of a gas: (1) pressure, (2) volume, and (3) temperature. For allABSOLUTE PRESSUREAbsolute pressure, normally expressed in terms of pounds per square inch absolute (psia), is defined as the pressure existing above a perfect vacuum. Therefore in the air around us, absolute pressure and atmospheric pressure are the same.GAUGE PRESSUREA pressure gauge is calibrated to read 0 psi regardless of elevation when not connected to a pressure producing source. The absolute pressure of a closed system will always be gauge pressure plus atmospheric pressure. At sea level, atmospheric pressure is 14.7 psi, therefore, at sea level, absolute pressure will be gauge pressure plus 14.7. Pressures below 0 psig are actually negative readings on the gauge, and are usually referred to as inches of mercury vacuum. A refrigeration compound gauge is calibrated in the equivalent of inches of mer-cury for negative readings. Since 14.7 psi is equivalent to 29.92 inches of mercury, 1 psi is approximately equal to 2 inches of mercury on the gauge dial. In the vacuum range, below 0 psig, 2 inches of mercury vacuum is approximately equal to a -1 psig.It is important to remember that gauge pressure is only relative to absolute pressure. Table 1-1 shows rela-tionships existing at various elevations assuming that standard atmospheric conditions prevail.Table 1-1Pressure Relationships at Varying AltitudesAltitude(Feet)PSIG PSIA InchesHg.BoilingPoint ofWater0014.729.92212°F1000014.228.85210°F2000013.727.82208°F3000013.226.81206°F4000012.725.84205°F5000012.224.89203°F Table 1-1 shows that even though the gauge pressure remains at 0 psig regardless of altitude, the absolute pressure does change. The absolute pressure in inchesof mercury indicates the inches of mercury vacuum thata perfect vacuum pump would be able to reach at the stated elevation. At 5,000 feet elevation under standard atmospheric conditions, a perfect vacuum would be 24.89 inches of mercury. This compares to 29.92 inchesof mercury at sea level.At very low pressures, it is necessary to use a smaller1-5© 1968 Emerson Climate Technologies, Inc.All rights reserved.practical purposes, air and highly superheated refriger-ant vapors may be considered perfect gases, and their behavior follows this relationship:Pressure One x Volume One = Pressure Two x Volume Two Temperature One Temperature TwoThis is most commonly stated, P 2V 2T 2P 1V 1T 1= .Although the "perfect gas" relationship is not exact, itprovides a basis for approximating the effect on a gas with a change in one of the three factors. In this relation-ship, both pressure and temperature must be expressed in absolute values, pressure in psia, and temperature in degrees Rankine or degrees Fahrenheit above abso-lute zero (°F plus 460°). Although not used in practical refrigeration work, the perfect gas relation is valuable for scientific calculations and is helpful in understanding the performance of a refrigerant vapor.One of the problems of refrigeration is disposing of the heat that has been absorbed during the cooling process. A practical solution is achieved by raising the pressure of the vapor so that its saturation or condensing tem-perature will be sufficiently above the temperature of the available cooling medium (air or water) to assure efficient heat transfer. This will provide the ability of the cooling medium to absorb heat from the refrigerant and cool it below its boiling point (dew point). When the low pressure vapor with its low saturation temperature is drawn into the cylinder of a compressor, the volume of the gas is reduced by the stroke of the compressor piston. The vapor is discharged as a high pressure high temperature vapor and is readily condensed because of its high saturation temperature.If refrigerant R-22’s pressure is raised to 195 psig, its saturation temperature will be 100°F (37.8°C). If the cooling medium’s temperature is lower than 100°F, heat will be extracted from the R-22 and it will be condensed, converted back to a liquid.SPECIFIC VOLUMESpecific volume of a substance is defined as the number of cubic feet occupied by one pound (ft 3/lb). In the case of liquids and gases, it varies with the temperature and the pressure to which the fluid is subjected. Following the perfect gas law, the volume of a gas varies with both temperature and pressure. The volume of a liquid varies with temperature. Within the limits of practical re-frigeration practice, it is regarded as non-compressible. Specific volume is the reciprocal of density (lb/ft 3).DENSITYThe density of a substance is defined as weight perunit volume. In the United States, density is normally expressed in pounds per cubic foot (lb./ft 3). Since by definition, density is directly related to specific volume, the density of a vapor may vary greatly with changes in pressure and temperature, although it still remains a vapor, invisible to the naked eye. Water vapor or steam at 50 psia pressure and 281°F temperature is over 3 times as heavy as steam at 14.7 psia pressure and 212°F.Refrigerant 22 vapor at 76 psig and at 45°F has a density of 1.66 lb/ft 3. At 150 psig and at 83°F, the refrigerants density is 3.02 lb/ft 3 or 1.82 times as heavy.PRESSURE AND FLUID HEADIt is frequently necessary to know the pressure created by a column of liquid, or possibly the pressure required to force a column of refrigerant to flow a given vertical distance upwards.Densities are usually available in terms of pounds per cubic foot, and it is convenient to visualize pressure in terms of a cube of liquid one foot high, one foot wide, and one foot deep. Since the base of this cube is 144 square inches, the average pressure in pounds per square inch is the weight of the liquid per cubic foot di-vided by 144. For example, water weighs approximately 62.4 pounds per cubic foot, the pressure exerted by 1 foot of water is 62.4 ÷ 144 or .433 pounds per square inch. Ten feet of water will exert a pressure of 10 X .433 or 4.33 pounds per square inch. The same relation of height to pressure holds true, no matter what the area of a vertical liquid column. The pressure exerted by other liquids can be calculated in exactly the same manner if the density is known.The density of liquid refrigerant R-22 at 45°F, 76 psig is 78.8 lb./ft 3. The pressure exerted by one foot of liquid R-22 is 78.8 ÷ 144 or .55 psig. A column of liquid R-22 10 feet high would then exert a pressure of 5.5 psig. At 100°F liquid temperature, the density is 71.2 lb./ft 3. A one foot column then exerts a pressure of .49 psig. A ten foot column exerts a pressure of 4.9 psig.Comparing other refrigerants at 45°F , R-404A has a den-sity of 70.1 lb./ft 3. It then exerts a pressure of .49 psig per foot of lift. R-134a has a density of 79.3 lb./ft 3, therefore it exerts a pressure of .55 psig per foot of lift.Fluid head is a general term used to designate any kind of pressure exerted by a fluid that can be expressed in terms of the height of a column of the given fluid. Hence a pressure of 1 psi may be expressed as being equivalent to a head of 2.31 feet of water. (1 psi ÷ .433 psi/ft. of water). In air flow through ducts, very small pressures are encountered, and these are commonly1-6。
制冷技术发展史
制冷技术发展史
《制冷技术发展史》
嘿，你知道吗，制冷技术这玩意儿啊，那可是有一段相当有趣的发展历程呢！
想当年啊，我记得小时候，家里还没有冰箱呢。
一到夏天，那可真是热得要命。
每次我跑出去玩得满头大汗回来，就特别渴望能有个凉飕飕的东西来降降温。
那时候，我们就只能用井水来冰西瓜。
把西瓜放进一个桶里，然后吊到井里去，等过一阵子再捞上来，哇，那西瓜吃起来也有那么点凉爽的感觉呢。
后来啊，慢慢有了那种老式的冰箱，就是那种上面冷冻下面冷藏的。
我还记得第一次看到冰箱的时候，那可真是稀奇得不行，感觉就像发现了一个神奇的宝贝。
那时候，家里人会把做好的饭菜放进去，第二天还能吃。
而且到了夏天，还能自己做冰棍呢！把糖水倒进模具里，放进冷冻室，等上一阵子，就能吃到自制的冰棍啦，那感觉，真的太棒啦！
再后来呢，冰箱的技术越来越先进啦。
什么风冷的、无霜的，各种各样的功能都有。
而且啊，不只是冰箱，空调也越来越普及了。
夏天一到，大家都躲在空调屋里，舒舒服服的，再也不用像以前那样热得难受啦。
你看，从以前只能用井水冰西瓜，到现在有这么先进的制冷技术，这变化可真是太大啦！这就是科技的力量呀，让我们的生活变得越来越凉爽、越来越舒适呢！制冷技术的发展，真的是给我们带来了太多的便利和快乐呀！
哎呀，我现在一想到以前没有制冷技术的日子，就觉得还是现在好啊，哈哈！
这就是制冷技术的发展史，一段充满变化和惊喜的历程呢！。
制冷技术的发展与应用
制冷技术的发展与应用随着科技的不断进步和人类对生活质量要求的提高，制冷技术在现代社会中扮演着越来越重要的角色。
通过制冷技术，人类能够轻松制造出适合各种环境的物品和设备，同时也能为人类带来更加舒适的生活体验。
在这篇文章中，我将会从制冷技术的历史、现状以及未来发展的角度，对制冷技术进行探讨。
一、历史要说制冷技术的历史，我们就不得不提到1805年英国物理学家William Thomson，也称作Kelvin。
Kelvin在研究热力学时发现，对于一种物质来说，在压缩时耗费的热能和扩张时获得的热能是相等的。
这一现象被称作Kelvin效应。
通过Kelvin效应，科学家们开始将压缩和膨胀应用到制冷领域。
1842年，美国物理学家John Gorrie成功地利用制冷机制造出了冰块，用以给黄热病患者敷降温药物。
但是，制冷技术的本质发展是在20世纪初期。
1902年，Willis Haviland Carrier发明了第一个实用化的空调系统，为工业生产带来了革命性的变革。
此后，随着电气技术和材料科学的快速发展，制冷技术得到了极大的进步与发展。
二、现状现在全球制冷技术的应用范围越来越广，不仅在家用电器中得到广泛的应用，同时在工业、航空、农业、医疗等多个领域都占据着重要地位。
从集中供冷、电子制冷、人体制冷等多个方面来说，现代的制冷技术已经非常成熟。
特别是近些年，随着节能技术和环保技术的发展，制冷技术也得到了极大地提高。
比如，现在冷库、制冷车和冷链物流等行业中，使用了大量的环保型制冷剂，这些制冷剂可以在循环中不断利用，不仅带来了更加可持续的发展理念，同时也更加符合人们的环保意识。
三、未来在未来的几年里，制冷技术的发展仍然会继续向前推进。
首先，因为全球气温的逐年上升，未来人们对于高效制冷系统，能够在节能与降低排放的同时，保持室内外温度平衡的需求将越来越大。
为此，科学家们正在不断探索新技术，研发新型制冷机、制冷剂以及新型的风机和电机等关键核心技术，将制冷技术不断推向更高的高度。
空调的起源及发展
空调编辑[kōng tiáo]空调即空气调节（air conditioner），是指用人工手段，对建筑/构筑物内环境空气的温度、湿度、洁净度、速度等参数进行调节和控制的过程。
一般包括冷源/热源设备，冷热介质输配系统，末端装置等几大部分和其他辅助设备。
主要包括水泵、风机和管路系统。
末端装置则负责利用输配来的冷热量，具体处理空气，使目标环境的空气参数达到要求。
中文名空调外文名air conditioner起源公元前1000年发展20世纪初期性质温度调节工具著名品牌格力、大金、海尔等目录1发展历史▪起源▪制冷剂的发展▪普及2效率评估3空调种类4组成结构▪压缩机▪冷凝器▪蒸发器▪四通阀▪毛细管组件5工作原理6拆装方法7原理▪功能降温▪其他▪分类号▪常用组合▪命名表示▪外观演变▪原则8匹数的选择▪类型的选择▪认证标志▪安装位置▪保养维护▪清洗方法▪注意事项▪故障判断1发展历史编辑起源公元前1000年左右，波斯人已发明一种古式的空气调节系统，利用装置于屋顶的风杆，以外面的自然风穿过凉水并吹入室内，令室内的人感到凉快。
空调空调19世纪，英国科学家及发明家麦可·法拉第（Michael Faraday），发现压缩及液化某种气体可以将空气冷冻，此现象出现液化氨气蒸发时，当时其意念仍留于理论化。
1842年，佛罗里达州医生约翰·哥里（John Gorrie）以压所落成的新大楼设有中央空调。
一名新泽西州Hoboken的工程师Alfred Wolff协助设计此崭新的空气调节系统，并把技术由纺织厂迁移至商业大厦，他被认为是令工作环境变得凉快的先驱之一。
1902年后期，首个现代化，电力推动的空气调节系统由威利斯·开利（1876年-1950年）发明。
其设计与Wolff的设计分别在于并非只控制气温，亦控制空气的湿度以提高纽约布克林一间印刷厂的制作过程质素。
此技术提供了低热度及湿度的环境，令纸张面积及油墨的排列更准确。
雅思阅读history of refrigeration
雅思阅读history of refrigeration
【最新版】
目录
1.制冷技术的起源和发展
2.制冷剂和制冷原理
3.制冷技术的应用
4.现代制冷技术的创新和发展
正文
一、制冷技术的起源和发展
制冷技术的历史可以追溯到公元前的中国和埃及，当时的人们已经开始利用天然冰来冷藏食物。
直到 19 世纪，制冷技术才开始得到快速的发展和广泛应用。
二、制冷剂和制冷原理
制冷剂是制冷技术的核心，其工作原理主要是利用制冷剂在不同温度下的吸热和放热特性，通过压缩和膨胀过程，将热量从低温环境转移到高温环境。
三、制冷技术的应用
制冷技术的应用领域非常广泛，包括家用冰箱、空调、冷库等。
尤其在食品工业、医药行业以及科学研究等领域，制冷技术起着至关重要的作用。
四、现代制冷技术的创新和发展
随着科技的进步和社会的发展，现代制冷技术也在不断创新和发展。
比如，节能环保的制冷技术和智能制冷技术的出现，都为制冷技术的未来发展提供了新的可能性。
总的来说，制冷技术的历史虽然悠久，但其发展却从未停止。
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制冷技术发展的历史
在史前时代，人类已经发现在食物缺少的季节里，如果把猎物保存在冰冷的地窖里或埋在雪里，就能保存更长的时间。
在中国，早在先秦时代已经懂得了采冰，储冰技术。
希伯来人，古希腊人和古罗马人把大量的雪埋在储藏室下面的坑中，然后用木板和稻草来隔热，古埃及人在土制的罐子里装满开水，并把这些罐子放在他们上面，这样使罐子抵挡夜里的冷空气。
在古印度，蒸发制冷技术也得到了应用。
当一种流体快速蒸发时，它迅速膨胀，升起的蒸汽分子的动能迅速增加，而增加的能量来自周围的环境中，周围环境的温度因此而降低。
在中世纪时期，冷却食物是通过在水中加入某种化学物质像硝酸钠或硝酸钾，而使温度降低，1550年记载冷却酒就是通过这种方法。
这就是制冷工艺的起源。
在法国冷饮是在1660年开始流行的。
人们用装有溶解的硝石的长颈瓶在水里旋转来使水冷却。
这个方法可以产生非常低的温度并且可以制冰。
在17世纪末，带冰的酒和结冻的果汁在法国社会已非常流行。
第一次记载的人工制冷是在1784年，威廉库伦在格拉斯各大学作了证明。
库伦让乙基醚蒸汽进入一个部分真空的容器，但是他没有把这种结果用于任何实际的目的。
在1799年冰第一次被用作商业目的，从纽约市的街道运河运往卡洛林南部的查尔斯顿市，但遗憾的是当时没有足够的冰来装运。
英格兰人Frederick Tuder和Nathaniel Wyeth看到了制冰行业的巨大商机，并且在18世纪上半叶，通过自己的努力革新了这个行业。
Tudor主要从事热带地区运冰，他尝试着安装隔热材料和修建冰房，从而使冰的融化量从66%减少到8%，Wyeth发明了一种切出相同冰块的方法，即快速又便捷，从而使制冰业发生了革命性变化，同时也减少了仓储业，运输业和销售业由于管理技术所造成的损失。
在1805年，一名美国发明者Oliver Evans设计了第一个用蒸汽代替液体的制冷系统，但Evans从来没有制造出这种机器。
不过美国的一位内科医生John. Gorrie制造了一个相似的制冷机器。
在1842年，弗洛雷达医院的这名美国内科医生John. Gorrie为了给黄热病患者治疗，他设计和制造了一台空气冷却装置给病房降温。
他的基本原理是：压缩一种气体，通过盘管使它冷却，然后膨胀使其温度进一步降低，这也就是今天用得最多的制冷器。
后来John. Gorrie停止仅在医院的实践，长期的深入到制冰实验中，在1851年获得关于机械制冰的第一项专利。
商业制冷被认为是起源于1856年，一名美国商人Alexander. C. Twinning 最先开创。
不久，一名澳大利亚人James Harrison检验了Gorrie和Twinning 所用的制冷机并把蒸汽压缩式制冷机介绍给了酿造和肉类食品公司。
在1859年，法国的Fredinad. Carre发明了一种更加复杂的制冷系统。
不
（氨像以前的压缩机用空气做制冷剂，Garre的设备用快速蒸发的氨做制冷剂。
比水液化时的温度低，因此可以吸收更多的热量）Garre的制冷机得到了广泛应用，并且蒸汽压缩式制冷至今仍是应用最广泛地的制冷方法。
但是当时这种制冷机成本高，体积大，系统复杂，再加上氨制冷济有毒性，因此阻碍了这种制冷机在家庭中的普遍应用。
许多家庭的冰柜仍使用当地制冷工厂提供的冰块。
从1840年开始，运输牛奶和黄油用到了空调汽车。
到1860年，制冷技术主要运用在海产品和日常用品的冷藏运输上。
1876年底特律市密歇根州的一名叫J.B Sutherland的人获得了人工制冷汽车专利。
他设计了一种带有冰室的绝热汽车。
空气从顶部流过来，通过冰室，利用重力然后在汽车内循环。
在1867年，伊利诺斯州的Parker Earle制造了第一辆用来运输水果的空调汽车，通过伊利诺斯州中央铁路运送草莓。
每个箱子里装100磅冰和200夸脱草莓。
直到1949年Fred Jones发明了一种顶置式制冷装置，并获得了专利。
1870年，在纽约的布鲁克林镇，S. Liebmanns 的太阳酿造公司开始用吸收式机械，这是美国北部酿造业广泛运用制冷机械的一个开端。
在18世纪70年代，商业制冷在啤酒厂中占主要的地位。
到了1891年，几乎所有的啤酒厂都装配有制冷机器。
天然冰供应本身已发展成为一个行业，许多公司都跻身该行业，导致价格下降。
并且冷藏用冰已相当普遍，到了1879年，在美国有35家商业制冰厂，10年之后就超过了200家，到了1909年达2000家。
所有因制冰废弃的池塘不再安全，甚至Thoreaus Walden池塘，1847年每天有1000吨的冰从那里抽取。
但是，随着时间推移，冰不仅作为冷藏的代名词，也变成了健康问题。
《热与冷》的合著者，Bern Nagengast说：“好资源越来越难找到了。
到了1890年代，由于污染物和污水的排放，天然冰成了一个问题。
”这个问题首先出现在酿造行业，然后是肉食和乳制品公司。
由机械制冰产生的机械制冷为这个问题的解决提供了方法。
卡尔保罗在1895年为生产液态空气制定了一个大型的计划，用6年时间发明了一种使液态的纯氧从液态空气中分离出来的方法，这导致大量的公司都转而开始使用氧气（例如，在钢铁制造业）。
虽然肉食品厂，啤酒厂接受制冷技术要慢，但最后他们也都采用了制冷技术。
1914年，美国几乎所有的肉联厂都安装了制冷机械的氨压缩机系统，它每天的制冷能力超过90000吨。
尽管制冷有其固有的优势，但本身也存在问题。
制冷剂，像二氧化硫和氯甲烷可以使人致死。
氨一旦泄漏，也同样具有强烈的毒性。
直到1920年，Frigidaire公司开发了几种人工合成制冷剂交氟氯甲烷或CFCS，制冷工程师才找到可接受的替代品。
这就是人们所共知的新的代替物氟利昂。
在化学上，氟利昂是甲烷(CH4)里的4个氢原子被两个氯原子和两个氟原子所代替。
除了分子量大之外，无臭无毒。
不久制冰业，酿造业和肉食业是制冷发展的主要受益者。
其他企业也深受制冷发展所带来的好处。
例如，在金属制造也里，机械制冷帮助餐具和工具冷硬成型。
因为制冷将送进高炉的空气除湿，钢铁产量增加，钢铁业得到了发展。
纺织厂把制冷用在丝光处理里，漂白，染色。
制冷对炼油厂来说很重要，同样对造纸厂、制药厂、肥皂厂、胶水厂、明胶厂、照片材料厂一样。
毛皮制品的贮存可以用冷库杀死飞蛾。
制冷可以帮助花圃和花店，满足季节性的需要，因为，剪掉的花可以持续比较长的花期。
更有甚者，在医学保存人体上的应用。
饮食行业，包括酒店、饭店、酒吧，饮料业为冰提供了很大市场。