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1、制冷剂的发展趋势与环境的可持续发展摘要： 论述了当前使用的制冷剂以及其存在的问题，指出现行制冷剂对臭氧层的破坏作用及引起的温室效应，将严重影响了环境的可持续发展。总结了当前制冷剂的替代工作及取得的成果。在论述可持续发展概念的基础上分析了制冷剂的替代研究与环境的可持续发展的关系，得出了是环境的可持续发展的要求推动了制冷剂的替代研究工作，并为替代研究指明了方向，同时制冷剂的替代进一步促进了环境的可持续发展。总结了在环境可持续发展要求下的制冷剂的发展趋势。关键词： 制冷剂替代 可持续发展1引言目前制冷空调行业中使用的制冷剂多为CFC（氯氟烃的统称）和HCFC（含氢氯氟烃）。这些物质由于对臭氧层具有破
2、坏作用并产生温室效应，因此其替代研究已成为热点课题1。本文在回顾制冷剂发展的历史中，发现制冷剂的替代发展有两条主线。一条是提高系统的能效比，另一条就是可持续发展的环境观。随着人们环保意识的增强，可持续发展的观点越来越深入人心。因此作者认为，在当前的制冷剂替代研究中，应首先考虑对环境的可持续发展。2当前的制冷剂与制冷剂的替代2.1 当前的制冷剂及其存在的问题制冷剂的发展经历了三个阶段：第一阶段，从1830年到1930年，主要采用NH3、CO2、H2O等作为制冷剂，它们有的有毒，有的可燃，有的效率低，用了约100年的时间。第二阶段，从1930年到1990年，主要采用CFCs和HCFCs制冷剂，使用
3、了约60年。第三阶段，从1990年至今，进入了以HFCs（含氟烃）为主的时期。由于行业发展的惯性，目前使用较多的制冷剂是CFCs和HCFCs，其次是HFCs。（对于CFCs发达国家已于1996年1月1日起禁止生产和使用，但一些发展中国家仍然在使用。）CFCs的禁用是因为CFCs会在大气中分裂并释放出破坏臭氧层的氯原子。据UNEP(联合国环境规划署)提供的资料，如果平流层的臭氧总量减少1，预计到达地面的有害紫外线将增加2。保护臭氧已经引起了各国的高度重视，成为一项全球性的紧迫任务。而HCFCs与CFCs同样能够破坏臭氧，两者只不过是所含的氯原子多少不同而已。同时CFCs、HCFCs和新一代HFC
4、s制冷剂都被认为是温室气体，它们对全球气候变暖影响的大小，取决于它们吸收红外能量的能力和它们在大气中延续的时间，可用GWP(全球变暖潜值)来度量它们对全球变暖作用的大小，其大小是相对于CO2的温室效应而言的，规定CO2的GWP值为1。物质对于臭氧层破坏能力的大小是以ODP（大气臭氧层损耗潜能值）来衡量的，以CFC11为基准，规定CFC11的ODP值为1。部分制冷剂的ODP和GWP值见表：物质ODPGWPCFC11(R11)11500CFC12(R12)14500HCFC22(R22)0.05510HFC32(R32)0CFC113(R113)0.82100CFC114(R114)15500HC
5、FC123(R123)0.0229HCFC124(R124)0.02150HFC125(R125)0860HFC134a(R134a)0420HCFC141b(R141b)0.08150HCFC142b(R142b)0.08540HFC143a(R143a)01800HC600a(R600a)015由于温室效应将引起气候变化，目前国际社会所讨论的气候变化问题，主要是指温室气体增加产生的气候变暖问题。近年来，世界各国出现了几百年来历史上最热的天气，给各国造成了巨大经济损失。人类对气候变化，特别是气候变暖，所导致的气象灾害的适应能力是相当弱的，需要采取行动防范，因为现行的制冷剂对环境的巨大的破坏作
6、用，促使着人们积极的寻求能够与环境的可持续发展相适应的新型替代制冷剂。2.2 制冷剂的替代根据蒙特利尔议定书CFCs在发达国家已经被禁用，HCFCs因为对臭氧仍具有破坏作用也即将被淘汰。由于GWP较高，京都议定书将替代CFCs和HCFCs的HFCs物质列入限控物质清单中，要求发达国家控制HFCs的排放。所有这些都对制冷剂的替代研究提出了更高的要求。因此理想的替代制冷剂除应有较低的ODP值和GWP值外，还应具有良好的安全性、经济性、优良的热物性等优点，争取做到既环保又节能。新型的替代制冷剂主要包括人工合成型和天然型两大类，有单一工质和混合工质两个方面，混合工质又可分为共沸混和物、近共沸混和物和非
7、共沸混和物三种。目前合成制冷剂方面主要有以下几种：1）R134aR134a的ODP0，GWP420，不可燃，无毒，无味，使用安全，其热物性质与R12十分接近，可用来替代R12，用于汽车空调和家用冰箱等领域。但使用R134a，会使能耗增大，且与CFC12用的润滑油不相溶，与材料的兼容性方面也不同CFC-12。另外它还是一种温室效应气体，所以仍然存在一定的缺陷。2）R152a从物化性方面看HFC-152a也与CFC-12接近，用R152a替代R12后能耗可降低37，但其在空气中含量达4.816.8时具有可燃性，因此推广使用收到一定的限制。而它可与其它物质混合，组成非共沸混合物来替代CFC-12。3
8、）R410AR410A是近共沸混合制冷剂，是由质量分数为50R32和50R125组成。ODP0，主要用来替代R22，单位容积制冷量较大，传热性能及流动性能较好，但同温度下压力值比R22高约60。4）R407CR407C是非共沸混合制冷剂，是由质量分数为23的R32、25的R125和51的R134a组成，ODP0，单位容积制冷量大，但传热性能较差。天然制冷剂方面主要有：5）碳氢化合物6目前作为制冷剂应用的碳氢化合物主要是丙烷（R290）、丁烷（R600）和异丁烷（R600a）等，其中R600a已在欧洲和一些发展中国家广泛用于冰箱中，并且它符合京都议定书的要求，ODP0，GWP15，环保性能好，成
9、本低，运行压力低，噪声小，但其易燃，易爆。此外R290和R600a组成的混合制冷剂也有一定的发展使用。6）氨（R717）氨已被使用达120年之久而至今仍在使用。其ODP=0、GWP=0，具有优良的热力性质，价格廉且容易检漏。不过氨有毒性而且可燃，应当引起注意，不过一百多年的使用记录表明，氨的事故率是很低的，今后必须找到更好的安全办法，如减少充灌量，采用螺杆式压缩机，引入板式换热器等等。然而，其油溶性、与某些材料不容性、高的排气温度等问题也需合理解决。看来，NH3会有更大的市场份额。7）二氧化碳（R744）CO2是自然界天然存在的物质， ODP0， GWP=1。来源广泛、成本低廉，CO2安全无毒
10、，不可燃，适应各种润滑油常用机械零部件材料，即便在高温下也不分解产生有害气体。CO2的蒸发潜热较大，单位容积制冷量相当高，故压缩机及部件尺寸较小；绝热指数较高K=1.30，压缩机压比约为2.53.0，比其它制冷系统低，容积效率相对较大，接近于最佳经济水平，有很大的发展潜力。3.1制冷剂的替代中的可持续发展观当前环境变暖引起的气候变化，臭氧层空洞等已成为全球性的环境问题，如果任其发展下去将对人类的生存和发展构成严峻的挑战。因此在制冷剂的替代研究过程中应该加强对生态环境的保护意识，不能只看到眼前的利益，而同时要注重生态环境与人类的协调的，可持续的发展。可持续发展的核心是经济发展与保护资源、保护生态
11、环境的协调一致，是为了让子孙后代能够享有充分的资源和良好的自然环境。通过近年来制冷剂替代工作的进展，我们可以看到人们不再只注重制冷剂的热物性，而更加注重其环保性。在蒙特利尔议定书签订以前制冷剂的研究一般以良好的热力学性质和物理、化学性质等为主，如CFC系列的R11，R12等都具有良好的热力性能和化学稳定性，且无毒，不燃，不爆等，但对臭氧层有很大的破坏作用，且能够引起温室效应。在蒙特利尔议定书签订以后，在制冷剂的研究替代中首先考虑到的是减小制冷剂对臭氧的破坏作用，比如HCFC系列的R22虽然仍对臭氧有破坏作用但比R11和R12小的多。而HFC制冷剂如R134a已对臭氧没有任何破坏作用。1997年
12、签订的京都议定书对于制冷剂的替代提出了很高的要求，也更加顺应了环境的可持续发展的要求，其不但要求替代制冷剂要有较低的ODP，而且具有较低的GWP，这样HFCs也面临淘汰的危险。从上面这些内容可以看出，在制冷剂的替代中是环境的可持续发展这只无形的大手在起着作用，它不但推动这制冷剂的替代研究工作的发展，而且也为制冷剂的发展指明了发展方向。3.2制冷剂的发展趋势总得来说制冷剂的发展趋势应该满足生态环境可持续发展的要求，并且推动其进一步发展。根据可持续发展中经济发展与保护资源、保护生态环境的协调一致的核心要求，制冷剂的发展方向有两个：一个是环保，使用绿色环保的制冷剂已经是大势所趋，绿色环保制冷剂可以是
13、合成的，也可以是天然的，虽然合成的环保制冷剂也对臭氧不会造成破坏，但从地球生态的可持续发展来看天然制冷剂是最理想的选择，因为天然制冷剂本来就是地球生态系统中存在的，无论是使用还是排放到环境中，取之于自然回之于自然，对环境的影响比合成制冷剂都小的多，相信随着技术的不断进步，天然制冷剂必将大有发展。第二个是节能，随着人们生活水平的提高制冷空调等设备越来越普及，同时其消耗的大量的能源也越来越引起人们的注意，今夏我国18个省市出现电力紧缺问题，中国电监会的一项调查显示，供需矛盾加剧造成今夏电力吃紧，其中空调制冷负荷快速增长是不可忽视因素。今夏我国华东、华中、华南地区持续高温，空调制冷负荷猛增。华东电网
14、、南方电网、华中电网空调制冷负荷比重已超过30，个别省电网甚至接近40。而电能的产生又要消耗大量的化石燃料，如煤、石油等，不但造成大量的不可再生能源的消耗，而且燃烧产物如CO2等还可引起温室效应等环境问题。因此除了改进制冷技术外还可从制冷剂上下手，通过研制新型节能制冷剂降低制冷空调设备的能耗也是一个发展方向。综上所述，制冷剂的发展是与环境保护和地球生态环境的可持续发展密切相关的，制冷剂的发展趋势体现了环境的可持续发展的要求。The evelopment trend of refrigerant and environmental sustainable developmentAbstract:
15、 the paper discusses the current refrigerants and its existing problems, points out that the destruction of the ozone layer and the refrigerant to cause the greenhouse effect, will seriously affect the sustainable development of environment. Summarizes the current alternative refrigerant and achieve
16、ments. Based on the discussion of the concept of sustainable development on the analysis of the relationship between sustainable development and environment research of alternative refrigerants, the environmental sustainability of requirements to promote the work of research on alternative refrigera
17、nts, and pointed out the direction for the research on alternative refrigerant replacement, and further promote the sustainable development of environment. Development trend of refrigerant in the environment under the requirements of sustainable development of the.Keywords: alternative refrigerant f
18、or sustainable development1 IntroductionRefrigerant currently used in refrigeration and air conditioning industry is CFC (chlorofluorocarbons collectively) and HCFC (hydrochlorofluorocarbons). These substances because of the damage to the ozone layer and make the greenhouse effect, so the substituti
19、on research has become a hot topic in 1. Based on the review of the history of the development of the refrigerant, found that there are two main refrigerant alternative development. One is the energy efficiency ratio of the system increased, the other one is the concept of sustainable development en
20、vironment. With increasing awareness of environmental protection, sustainable development view more and more win support among the people. The author thinks that, in the study of alternative refrigerant current, should first consider the sustainable development of environment.2 current refrigerants
21、and refrigerant2.1 the refrigerant and its existing problemsThe refrigerant has gone through three stages of development:The first stage, from 1830 to 1930, mainly NH3, CO2, H2O as refrigerant, some of them are toxic, combustible, and some low efficiency, for about 100 years.The second phase, from 1
22、930 to 1990, the main use of CFCs and HCFCs refrigerant, use about 60 years.The third phase, from 1990 to date, access to the HFCs (fluorinated hydrocarbon) dominated period.Due to the development of the industry of inertia, the refrigerant is currently using more CFCs and HCFCs, followed by HFCs. (
23、for CFCs developed countries in January 1, 1996 to ban the production and use, but some developing countries are still in use.)CFCs disable because of chlorine atoms in the atmosphere of CFCs will split and release the destruction of the ozone layer. According to UNEP (UNEP) to provide information,
24、if the total ozone stratosphere is expected to reduce 1%, harmful ultraviolet rays reach the ground will increase 2%. The protection of the ozone has already caused the attention of the world, become a urgent task.While HCFCs and CFCs can also destroy the ozone, which is only a chlorine atom contain
25、s many different. At the same time, CFCs, HCFCs and a new generation of HFCs refrigerant is considered a greenhouse gas, their impact on the global climate warming in size, depending on their ability to absorb infrared energy and they continue in the atmosphere of the time, available GWP (global war
26、ming potential) to measure their effects on global warming, the size, the size of relative to the greenhouse effect of CO2, CO2 GWP 1. The material for the destruction of the ozone layer capacity is ODP (atmospheric ozone depletion potential) to measure, based on CFC11, CFC11 ODP 1. ODP and GWP port
27、ion of the refrigerant value table:物质ODPGWPCFC11(R11)11500CFC12(R12)14500HCFC22(R22)0.05510HFC32(R32)0CFC113(R113)0.82100CFC114(R114)15500HCFC123(R123)0.0229HCFC124(R124)0.02150HFC125(R125)0860HFC134a(R134a)0420HCFC141b(R141b)0.08150HCFC142b(R142b)0.08540HFC143a(R143a)01800HC600a(R600a)015Because of
28、 the greenhouse effect will be caused by climate change, climate change is the discussion of international community, is mainly refers to the increase of greenhouse gases generated by climate warming. In recent years, the world has hundreds of years history of the hot weather, causing huge economic
29、losses to the country. Human impact on the climate change, especially climate warming, meteorological disasters caused by the ability to adapt is very weak, need to take action to prevent, because of the great effect of the current refrigerants damage to the environment, encourage people to actively
30、 seek to new alternative refrigerant to adapt with the sustainable development of the environment.2.2 alternative refrigerantAccording to the Montreal Protocol CFCs has been disabled in the developed countries, because HCFCs has destructive effect will be eliminated on ozone. Because the GWP is high
31、er, Kyoto Protocol substance HFCs will replace CFCs and HCFCs included the controlled substances list, requires developed countries to control the emission of HFCs. All of these alternative refrigerant research to put forward higher requirements. Therefore the ideal alternative refrigerant for its l
32、ow ODP value and GWP value, also has a good security, the economy, the thermal properties of many advantages, strive to achieve both environmental protection and energy saving.Alternative refrigerant model including synthetic and natural type two categories, there are two aspects of a single mixture
33、s, refrigerant mixture can be divided into the azeotropic mixture, near azeotropic mixture and non azeotropic mixture three.Synthesis of the refrigerant has following several:1) R134aR134a ODP = 0, GWP = 420, non flammable, non-toxic, tasteless, safe to use, its thermal properties are quite close to
34、 R12, and can be used to replace the R12, used for automobile air conditioners and refrigerators etc. But the use of R134a, the energy consumption increases, lubricating oil and CFC with 12 immiscible, is also different from the aspects of material compatibility CFC-12. And it is a greenhouse gas, s
35、o there are still some defects.2) R152aFrom material aspect of HFC-152a is similar to CFC-12, use R152a instead of R12 energy consumption reduced by 3% 7%, but the content of 4.8% - 16.8% in the air with combustible, thus promoting the use of receive certain limit. While it may be mixed with other s
36、ubstances, non azeotropic mixture instead of CFC-12.3) R410AR410A is the near azeotropic refrigerant mixture, by mass fraction of 50%R32 and 50%R125. ODP = 0, mainly used to replace R22, refrigerating capacity per unit volume is larger, better heat transfer performance and flow performance, but at t
37、he same temperature pressure value is higher than R22 60%.4) R407CR407C is a non azeotropic refrigerant mixture, by mass fraction of 23% R32, 25% R125 and 51% R134a, ODP = 0, refrigerating capacity per unit volume, but poor heat transfer characteristics.The main natural refrigerant:5) hydrocarbons 6
38、At present, as the hydrocarbon refrigerant applications are mainly propane (R290), (R600) butane and isobutane (R600a), which R600a has in Europe and some other developing countries, is widely used for refrigerator, and it accords with the Kyoto Protocol requirement, ODP = 0, GWP = 15, good environm
39、ental protection performance, low cost, low operating pressure, small noise, but the flammable, explosive. In addition, the mixed refrigerant R290 and R600a also have certain development use.6) ammonia (R717)Ammonia has been used for over 120 years and are still in use. The ODP=0, GWP=0, with therma
40、l properties, low price and easy leak detection. However, ammonia is toxic and flammable, attention should be given to more than one hundred years, but the use of ammonia records show that, the accident rate is very low, must find a safe way to a better future, such as reducing the filling quantity,
41、 the screw compressor, the heat exchanger and so on. However, the oil soluble, and some material can not be sex, high exhaust temperature and other issues also need a reasonable solution. It seems, NH3 will have a larger market share.7) carbon dioxide (R744)CO2 is a naturally occurring substances in
42、 the natural world, ODP = 0, GWP=1. Extensive sources, low cost, CO2 is safe and non-toxic, non flammable, to adapt to a variety of commonly used lubricating oil of mechanical parts materials, even in high temperature does not decompose harmful gases. CO2 the latent heat of evaporation is larger, th
43、e refrigerating capacity per unit volume is very high, so the compressor and components of small size; adiabatic index higher K=1.30, compressor pressure ratio is about 2.53.0, other than the refrigeration system is low, the volumetric efficiency is relatively large, close to the optimum level of ec
44、onomy, has great development potential.The sustainable development view in 3.1 refrigerant substitutionClimate change caused by the current environment warming, the depletion of the ozone layer has become a global environmental problem, if the situation continues to pose a serious challenge to human
45、 survival and development. Therefore in the research process of alternative refrigerant should be strengthened to protect the ecological environment consciousness, can not only see the immediate benefits, but at the same time, we should pay attention to the coordination of ecological environment and
46、 the human, sustainable development. Sustainable development is the core of the economic development and the protection of resources, coordination of the protection of the ecological environment, in order to let children can enjoy the full resources and good natural environment.In the refrigerant re
47、placement work in the recent years, we can see that people no longer focus only on the thermal properties of refrigerants, and pay more attention to the environmental protection. In the Montreal Protocol before signing on with good refrigerant thermodynamic properties and physical, chemical properti
48、es, such as the CFC series of R11, R12 has good thermal properties and chemical stability, non-toxic, non flammable, non explosive, but is very destructive to the ozone layer, And can cause the greenhouse effect. In the Montreal Protocol after signing, to consider in the research of alternative refrigerants first is to reduce the damage to the ozone of refrigerant, such as the HCFC series of R22 while still on the ozone destructive but much smaller tha