![]() R32 and R125 are seldom used as single refrigerants, but only in mixtures with particularly favorable thermodynamic properties.Some comments on the refrigerants presented in the table are given below: Table 5.1 The most common refrigerants among halogenated hydrocarbons. The most common HFC refrigerants available since the ban on HCFCs are presented in Table 5.1 (see also Figure 5.4): However, their impact on global warming is very large compared with traditional refrigerants. The hydrofluorocarbons are refrigerants that contain no chlorine and are not harmful to the ozone layer (ODP = 0, see section 5.3). Examples of hydrochlorofluorocarbons include R22, R123 and R124 (see Figure 5.3). The HCFCs contain less chlorine than CFCs, which means a lower ODP (see section 5.3). The hasty actions of the European Union that culminated in the ban of HCFCs, immediately for refrigeration and soon (2004 at the latest) for air conditioning, has upset the industry's programs and plans. However, and more importantly, it also shows the problems and indecisiveness surrounding the availability of HCFCs, which were officially indicated as temporary (until 2030) substitutes for CFCs. The slow phase-out of CFCs shows it is a costly process. On the contrary, the illegal market for this type of refrigerants flourishes worldwide, and it is estimated that no more than 50% of CFC systems worldwide have been upgraded. The conversion of equipment and systems using CFCs has not yet been completed. They have been banned since the beginning of the 90's because of their negative environmental impacts. CFC = ChloroFluoroCarbonsĬhlorofluorocarbons are refrigerants that contain chlorine. ![]() In the following section, different groups of refrigerants are discussed, some examples are given and their fields of application are described. The process is not easy, and although there are alternatives to old refrigerants, the new ones are usually not flawless. Following the discovery that some of these chemical compounds may be harmful to the environment, they are being replaced with more environmentally friendly alternatives (see Figure 5.2). Refrigerants are divided into groups according to their chemical composition. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |