This article is part of the Alternative Refrigerants special issue. In this issue of the Journal of Chemical& Engineering Data (JCED) we are pleased to present a collection of manuscripts showcasing new trends in refrigerants for application in improved cooling systems. The Montreal protocol has had an indisputable positive impact on the protection of the ozone layer by phasing out the manufacture and supply of ozone depletion potential (ODP) active agents such as chlorofluorocarbons (CFCs). However, the subsequent substitution of these substances with hydrofluorocarbons (HFCs) has created a second challenge, due to high global warming potentials (GWP) for most of the HFCs. As a result, new regulations and policies have appeared that aim to move toward more sustainable refrigeration systems. The European Union (EU) Regulation No. 517/2014 has prohibited all new commercial refrigerators and freezers containing fresh HFCs with GWPs higher than 2500 since the beginning of 2020, with the GWP limit reducing to 150 by 2022. The United States (US) is incentivizing the production of low GWP refrigerants (US-EPA, 2012) and restricting the use of abundant third generation commercial coolers (US-EPA, 2015). In addition, Kigali’s Amendment to the Montreal Protocol, signed in 2016, forces countries to phase out all high GWP refrigerants, starting in 2019 for the most developed countries. To comply with these policies, alternative low-GWP refrigerants, as well as new recycling technologies to reuse existing ones, are being sought in an attempt to mitigate the impact that these compounds have in climate change. Indeed, this is not an easy task, as the desired new refrigerants must have the right thermophysical properties, they must be intrinsically safe, and they must meet the environmental requirements when used in different cooling equipment. Hydrofluorolefins (HFOs) were recently introduced in the market as promising alternatives, given their attractive thermophysical properties and low GWP. However, as some of them are mildly flammable, their use as single compounds may be limited depending on the exact application. To mitigate this problem, the combination of HFOs and HFCs may be a viable option. Other systems, including carbon dioxide (CO₂) or other nonfluorinated substances, are also possibilities as the community searches for the right combination of thermophysical, environmental, and safety properties. Appropriate thermophysical properties, safety, and environmental impact are not the only requirements for improved operational refrigeration systems. The design of new refrigerants and the improvement of current ones require researchers to ascertain compatibility with lubricant oils. Lubrication oils are regularly used in the compressor of refrigeration cycles to minimize friction, diminish noise, and act as corrosion inhibitors. Oils frequently come in contact with refrigerants due to leakage affecting the efficiency or coefficient of performance (CoP), which depends on the gas–oil miscibility. Another important concern is related to the end of life of the refrigeration equipment and the need for developing efficient recovery techniques, so as to allow the recycling of substances. The need to understand the physicochemical behavior of all new or modified refrigeration systems and the urgency provided by the new and stricter regulations appearing worldwide have revitalized the field of refrigerants. Detailed knowledge of the thermophysical properties, either by experimental measurements or by means of simulation and modeling techniques, is a requirement for the design of optimal conditions in engineering applications of refrigeration cycles. In this JCED issue, you will find a review on refrigerant evolution, a wide variety of new experimental data for novel systems based on HFOs and blends involving other compounds, such as CO₂, and some additional contributions based on the analysis of lubricant compatibility and the study of alternative solvents for recovery and recycling. Indeed, it is a pleasure to introduce in this Special Issue, a series of relevant manuscripts that combine accurate experimental data with modern theoretical techniques, dealing with the development and understanding of alternative refrigerants. Views expressed in this editorial are those of the author and not necessarily the views of the ACS. This article has not yet been cited by other publications.

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替代制冷剂特刊序言

本文是 替代制冷剂特刊。在本期《化学与工程数据杂志》（JCED）中），我们很高兴地提供一系列手稿，这些手稿展示了制冷剂的新趋势，可用于改进的冷却系统。蒙特利尔议定书通过逐步淘汰生产和供应诸如氯氟烃（CFC）之类的臭氧消耗潜能（ODP）活性剂，对保护臭氧层产生了无可争议的积极影响。然而，由于大多数氢氟碳化物的高全球升温潜能值（GWP），随后用氢氟碳化合物（HFC）替代这些物质带来了第二个挑战。结果，出现了旨在朝着更可持续的制冷系统发展的新法规和政策。自2020年初以来，欧洲联盟（EU）第517/2014号法规禁止使用所有新的商业冰箱和冰柜，其中包含全球升温潜能值高于2500的新鲜氢氟碳化合物，到2022年，全球升温潜能值限制将降至150。美国正在鼓励生产低全球升温潜能值的制冷剂（美国环保局，2012），并限制使用大量的第三代商用冷却器（美国环保局，2015）。此外，2016年签署的《基加利《蒙特利尔议定书》修正案》迫使各国从2019年开始对所有发达国家逐步淘汰所有全球升温潜能值高的制冷剂。为了遵守这些政策，正在寻找替代的低全球升温潜能值的制冷剂，以及新的循环技术以重复利用现有的制冷剂，以减轻这些化合物对气候变化的影响。确实，这不是一件容易的事，因为所需的新制冷剂必须具有正确的热物理特性，它们必须本质安全，在不同的冷却设备中使用时，它们必须满足环境要求。氢氟烯烃（HFOs）由于其诱人的热物理性质和低全球升温潜能值，最近已作为有希望的替代品引入市场。然而，由于它们中的一些是轻度易燃的，因此取决于确切的应用，它们作为单一化合物的使用可能受到限制。为了减轻此问题，将HFO和HFC组合使用是可行的选择。其他系统，包括二氧化碳（CO HFO和HFC的组合可能是一个可行的选择。其他系统，包括二氧化碳（CO HFO和HFC的组合可能是一个可行的选择。其他系统，包括二氧化碳（CO₂）或其他非氟化物质，因为社区正在寻求热物理，环境和安全属性的正确组合，因此也是可能的。适当的热物理性质，安全性和环境影响并不是改进运行制冷系统的唯一要求。新制冷剂的设计和现有制冷剂的改进要求研究人员确定与润滑油的相容性。在制冷循环的压缩机中经常使用润滑油，以最大程度地减少摩擦，降低噪音并充当腐蚀抑制剂。由于泄漏影响效率或性能系数（CoP），因此油经常与制冷剂接触，这取决于气-油混溶性。另一个重要的关注点涉及制冷设备的寿命终止以及开发有效的回收技术以允许物质回收的需求。了解所有新的或改装的制冷系统的理化特性的需要以及全球范围内出现的新的更严格的法规所提供的紧迫性，使制冷剂领域焕发出了新的活力。通过实验测量或通过模拟和建模技术来详细了解热物理性质是设计制冷循环工程应用中最佳条件的要求。在这个 了解所有新的或改装的制冷系统的物理化学行为的需要以及全球范围内出现的新的更严格的法规所提供的紧迫性，使制冷剂领域焕发出了新的活力。通过实验测量或通过模拟和建模技术来详细了解热物理性质是设计制冷循环工程应用中最佳条件的要求。在这个 了解所有新的或改装的制冷系统的理化特性的需要以及全球范围内出现的新的更严格的法规所提供的紧迫性，使制冷剂领域焕发出了新的活力。通过实验测量或通过模拟和建模技术来详细了解热物理性质是设计制冷循环工程应用中最佳条件的要求。在这个在JCED期刊上，您将了解制冷剂的演变，基于HFO和涉及其他化合物（例如CO _2）的混合物的新型系统的各种新实验数据，以及基于润滑剂相容性分析和研究的一些其他贡献。用于回收和再循环的替代溶剂。确实，很高兴在本期特刊中介绍一系列相关手稿，这些手稿将准确的实验数据与现代理论技术相结合，处理替代制冷剂的开发和理解。本社论中表达的观点只是作者的观点，不一定是ACS的观点。本文尚未被其他出版物引用。