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Hasse Diagram Technique–A Useful Tool for Life Cycle Assessment of Refrigerants

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Destruction of the polar ozone layer and global climate change are proven consequences of various man-made volatile compounds of which substances used for air-conditioning systems or refrigeration units are important contributors. The Montreal and Kyoto Protocol regulate the phase-out of ozone-depleting substances and the reduction of greenhouse gas emissions. In the present work, the main focus is laid on emissions from air-conditioning (A/C) systems depending on the used refrigerants, and the comparison of life cycle assessment results by means of the Hasse Diagram Technique. Five refrigerants were ranked according to three parameters. Two Hasse Diagrams were drawn; one using the energy consumption during refrigerant production and compression of the refrigerants during operation of the A/C system, the other one additionally including the direct emissions during the total life cycle of the A/C system. According to this study, the refrigerants R152a and R290 have the smallest environmental impact. The two Hasse Diagrams clearly show that direct emissions of refrigerants are crucial within the life cycle of an A/C system. Due to its small GWP100, carbon dioxide (R744) has a better direct emission balance than hydrofluorocarbons and hydrocarbons. Next to energy and emissions values, other properties (e.g. toxicology, safety, energy efficiency…) are of importance when deciding which refrigerant can be recommended as substitute. But the more parameters are included, the more likely is it that incomparabilities in the Hasse Diagrams occur. Thus, when applying the Hasse Diagram Technique to LCA, not more than three parameters should be considered. Further studies are planned to examine the relative importance with re-spect to energy efficiency, environmental and human health of the various properties.
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... Another direction is the further development of the concept of stability fields, where still many questions (e.g. how to relate different stability fields if the G-space is more than two-dimensional) are open and must quickly be solved, as the application may have direct consequences for better substitutes of refrigerants (Restrepo et al., 2007;Weckert et al., 2007). We conclude that partial order is a general applicable tool just because of its conceptual simplicity, and it seems that the concepts derived from partial order fit very well to chemical problems, as typical questions in chemistry are answered in the form of series, nephelauxetic series, soft and hardness series, series of electronegativity, etc. ...
... Another direction is the further development of the concept of stability fields, where still many questions (e.g. how to relate different stability fields if the G-space is more than two-dimensional) are open and must quickly be solved, as the application may have direct consequences for better substitutes of refrigerants (Restrepo et al., 2007;Weckert et al., 2007). We conclude that partial order is a general applicable tool just because of its conceptual simplicity, and it seems that the concepts derived from partial order fit very well to chemical problems, as typical questions in chemistry are answered in the form of series, nephelauxetic series, soft and hardness series, series of electronegativity, etc. ...
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TEWI Analysis for Future A/C Systems Selection
  • C Petitjean
  • M B Yahia
  • G Guyonvarch
  • R Beauvis
Petitjean, C., Yahia, M.B., Guyonvarch, G., Beauvis, R. (1999): TEWI Analysis for Future A/C Systems Selection. Alternate Refrigerant Forum, June 30, Phoenix USA.