The first designers of refrigeration machines, Jacob Perkins in 1834, and others later in the 19th century, used ethyl ether (R-610) as the first commercial refrigerant. The reason is easy to understand if one has ever spilt this liquid on the hand and felt the effect. In fact, it was not particularly suitable to the purpose, however, being dangerous as well as requiring an excessive compressor volume. Other and more appropriate refrigerants, e.g. ammonia (R-717), carbon dioxide (R-744), ethyl chloride (R-160), isobutane (R-600a), methyl chloride(R-40), methylene chloride (R-30) and sulfur dioxide (R-764) were soon introduced, including air (R-729). Three of these refrigerants became very popular,i.e.,ammonia for refrigerators and other small units,sulfur dioxide for refrigerators and other small units, and carbon dioxide preferably for ships' refrigeration. A large number of substances were tried over the following years, with varying success.(制冷機(jī)的第一位設(shè)計(jì)者珀金斯(1834年)和后來者們(19世紀(jì))使用乙二乙醚(R610)作為第一代商業(yè)制冷劑?理由很簡(jiǎn)單,如果你曾經(jīng)將這種液體濺在手上,你就會(huì)感覺到這種效果?然而事實(shí)上二乙醚不是特別適合于做制冷劑,它不僅要求過多的壓縮機(jī)容積,而且還很危險(xiǎn)?進(jìn)而出現(xiàn)了更為合適的制冷劑,如氨(R717),二氧化碳(R744),氯乙烷(R160),異丁烷(R600a),氯甲烷(R40),二氯甲烷(R30)以及二氧化硫(R764),其中也包括空氣(R729)?這些制冷劑當(dāng)中有三種被普遍使用,即氨用于冷庫和其它小型制冷裝置,二氧化硫用于冰箱和其它小型制冷裝置,二氧化碳用于船用制冷裝置?后來,大量的物質(zhì)也被嘗試,并取得了不同程度的成功?)

In the early 1930s, the introduction of chlorofluorocarbons (CFCs) was revolutionary compared with the natural substances. In addition to their uses as refrigerants in refrigeration and air-conditioning systems, CFCs have been utilized as foam-blowing agents, aerosol propellants and cleaning solvents since 1950. The main arguments put forward in their favor were complete safety and harmlessness to the environment. Both of these claims have been proved wrong. Many accidents have occurred due to suffocation in the heavy gas, without warning, in below threshold spaces. It was evident that CFCs and related compounds contribute tremendously to the destruction of the stratospheric ozone layer and to the greenhouse effect (i.e., global climate change) which are considered among the most significant environmental problems. In fact, CFCs are greenhouse gases which give a combined contribution to incremental global warming of the same magnitude. The most abundant greenhouse gas is CO2?and the others are CH4, N2O, CFCs,etc. The effect of CFCs on global climate change may vary considerably, roughly contributing in the range 15–20% as compared to 50% for CO2. The interesting point is that in order to minimize global climate change, making reductions in CFC utilization seems to be easier than reducing fossil fuel use.Therefore,a full ban on these substances was essential.(在20世紀(jì)30年代初期,相對(duì)于自然工質(zhì)而言,氯氟烴(CFCs)被用作制冷劑是具有革命性的?自1950年以來,氯氟烴除被用作制冷系統(tǒng)和空調(diào)系統(tǒng)中的制冷劑外,它還被用作為發(fā)泡劑?氣溶膠噴射劑和洗滌劑?對(duì)其有利的主要論據(jù)是完全安全并對(duì)環(huán)境無害的?這兩種論據(jù)被證明是錯(cuò)誤的?在沒有得到任何警示的情況下,許多在有限空間內(nèi)因重氣體窒息死亡的事件發(fā)生?很顯然,CFCs和相關(guān)的混合物對(duì)臭氧層有極大的破壞作用,并有助于導(dǎo)致溫室效應(yīng)(即全球性氣候變化,被認(rèn)為是最嚴(yán)重的環(huán)境問題之一)?實(shí)際上,CFCs只是對(duì)全球性變暖有同樣貢獻(xiàn)的溫室氣體?量最大的溫室氣體是二氧化碳,其他的還包括CH4?N2O?CFCs等?CFCs對(duì)全球性氣候變化的影響變化非常大,大致貢獻(xiàn)比例在15-20%范圍內(nèi),而二氧化碳的貢獻(xiàn)比例為50%?有趣的是,為了使全球性氣候變化減到最小,減少CFC的利用比減少礦物燃料的使用似乎更容易?所以,對(duì)CFCs類物質(zhì)的全面禁止使用是至關(guān)重要的?在過去十年里,由于CFCs對(duì)臭氧層和全球氣候變化的影響,它在全世界范圍被禁止使用,盡管它曾經(jīng)是應(yīng)用最為廣泛的化學(xué)物質(zhì)?)

During the past decade CFCs have been banned worldwide as a result of their alleged effect on the stratospheric ozone layer and global climate change despite the fact that CFCs have been among the most useful chemical substances ever developed. During the past decade, research activities have been expanded tremendously to conduct ozone level measurements using various types of ground based or airborne equipment; of course, more recently satellite technology has become a prominent technique to provide more accurate findings about the ozone levels indifferent locations.(在過去十年里,基于地面設(shè)備或空中設(shè)備測(cè)量臭氧含量的研究活動(dòng)被極大的拓展?當(dāng)然,最近衛(wèi)星技術(shù)成為了一個(gè)突出的技術(shù),它能從不同方位更精確的測(cè)量臭氧水平?)

It is well known that the stratospheric ozone layer acts as a shield against harmful UV solar radiation. Nearly two decades ago, researchers discovered that chlorine released from synthetic CFCs migrates to the stratosphere and destroys ozone molecules and hence the ozone layer which was recognized as ozone layer depletion,known as one of the biggest environmental problems.In1987, 24 nations and the European Economic Community signed the Montreal Protocol to regulate the production and trade of the ozone depleting substances. This is considered as a landmark in refrigeration history.(眾所周知,平流層的臭氧層是防止有害的太陽紫外線輻射的防護(hù)物?近20年以前,研究員發(fā)現(xiàn),從CFCs釋放出的氯運(yùn)動(dòng)到平流層,破壞了臭氧分子及臭氧層?因此臭氧層衰減被認(rèn)為是最大的環(huán)境問題之一?1987年,24個(gè)國家和歐洲經(jīng)濟(jì)共同體簽署了蒙特利爾協(xié)議,用以控制臭氧衰減物質(zhì)的生產(chǎn)和交易?這被認(rèn)為是制冷史上的一個(gè)里程碑?)

This is by no means a unique experience. Similar predicaments have occurred following release to the environment of many other new chemicals. The extensive use of ever more new compounds is one of the big problems of our time. In this situation it does not seem very sensible to replace the CFC/HCFCs with a new family of related halocarbons, equally foreign to nature,to be used inquantities of hundreds of thousands of tons every year.(這絕不是唯一的?相似的困境還發(fā)生在許多排放到環(huán)境中的新化學(xué)物質(zhì)之上?對(duì)更多新化合物的廣泛的使用是我們這個(gè)時(shí)代最大的一個(gè)問題?在這種情況下,拋開物質(zhì)本性不說,用一種新的鹵烴取代每年成千上萬噸使用的CFC/HCFCs看起來是不明智的?)

Ingeneral,refrigerants are well known as the fluids absorbing heat during evaporation.These refrigerants, which provide a cooling effect during the phase change from liquid to vapor, are commonly used in refrigeration,air conditioning,and heat pump systems.(一般而言,制冷劑被認(rèn)為是在蒸發(fā)過程中吸收熱的流體?這些制冷劑,在從液態(tài)向氣態(tài)轉(zhuǎn)換的過程中產(chǎn)生冷卻效果,通常在制冷?空調(diào)和熱泵系統(tǒng)中被使用?)