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Energy, markets, and society
Published in Peter M. Schwarz, Energy Economics, 2023
Externalities from energy use that damage ecological systems could call for strong sustainability. In the 1980s, there was concern about a growing hole in the ozone layer, attributable to emissions of chlorofluorocarbons (CFCs) used in air conditioners and refrigerators. Preserving the ozone layer calls for strong sustainability, as humans have not achieved an alternative way of achieving this protection. However, the Montreal Protocol signed in 1987 was a global agreement to phase out CFCs. Fortunately, DuPont and other chemical companies were able to substitute other chemicals for CFCs in the refrigerating process, allowing the ozone hole to shrink over time. Unfortunately, substitutes such as hydrofluorocarbons (HFCs) are greenhouse gases that contribute to climate change.
Historical context
Published in John K. Pearson, Richard G. Derwent, Air Pollution and Climate Change, 2022
John K. Pearson, Richard G. Derwent
In 1985, Joe Farman of the British Antarctic Survey published evidence of the appearance of a ‘hole’ in the stratospheric ozone layer over Antarctica during each spring since his measurements began during the 1970s. A combination of aircraft flights over Antarctica and laboratory investigations subsequently revealed the causal mechanism behind the formation of the Antarctic ozone ‘hole’ to involve the exceedingly low temperatures found in the stratosphere over the Antarctic, polar stratospheric clouds and the chlorine liberated from the destruction of man-made CFCs in the upper stratosphere. Under the Montreal Protocol, CFCs were phased out and were replaced as refrigerants and foam blowing agents by hydrochlorofluorocarbons (HCFCs). But as the Antarctic ozone ‘hole’ grew larger in size each spring and ‘holes’ began to appear each spring in the Arctic ozone layer, these also had to be phased out. Hydrofluorocarbons (HFCs) were selected as replacement refrigerants and air-conditioning fluids, but they are potent greenhouse gases and are thus adding to global climate change.
Mechanism behind Sources and Sinks of Major Anthropogenic Greenhouse Gases
Published in Moonisa Aslam Dervash, Akhlaq Amin Wani, Climate Change Alleviation for Sustainable Progression, 2022
Tariq Mehmood, Muhammad Azher Hassan, Xinghua Li, Anam Ashraf, Sadia Rehman, Muhammad Bilal, Raphael M Obodo, Beenish Mustafa, Mehak Shaz, Saira Bibi, Awais Shakoor
Retrofit facilities, toxicological and environmental acceptability of HCFCs and HFC replacements, regulatory recycling scheme facilitating productive investment in development, rapid distribution and acceptance of technologies have replaced CH3CCI3. Hydrofluorocarbons (HFCs) are also known as greenhouse gases. They have a range of GWP owing to their relevant and positive radiative forcing effects. These gases possess comparatively very high GWP as compared to CO2, for instance, HFC-23 has GWP over 11,700. Since these gases have very little concentration in the atmosphere, their collective greenhouse effect is very less compared to CO2 (Kershaw, 2017).
Numerical simulation of condensation from isobutane vapour – air mixture
Published in International Journal of Ambient Energy, 2023
A. Charef, M. Feddaoui, M. Najim, A. Nait Alla, M. Hissouf
Combined heat and mass transfer problems are of importance in many engineering applications and have received a considerable amount of attention (Krishna, Anand, and Chamkha 2019; Krishna and Chamkha 2019, 2020; Krishna, Ahammad, and Chamkha 2021; Khan, Rasheed, and Salahuddin 2020, 2021a, 2021b; Jan et al. 2019; Hussain et al. 2021, 2022). Engineering applications involving condensing two-phase flow phenomena take place in heat pumps, air-conditioning, refrigeration and cooling systems. Most of the used HydroFluoroCarbon (HFC) refrigerants have a great Global Warming Potential (GWP). Consequently, HFC refrigerants having higher GWP will be substantially reduced or eliminated (Calleja-Anta et al. 2020). Hence, owing to the environmental problems and climatic changes, hydrocarbons have been increasingly recognised as the working fluid in several applications like refrigerator and heat pumps systems. The increasing awareness of environmental protection has led to a demand for natural refrigerants in the refrigeration and air conditioning industries. Hydrocarbons, in particular such as isobutane (R600a), are well known as perfect refrigerants. It has been verified to be employed as a long-term alternative refrigerant due to its less impact environmental and its good cooling performance.
A reactive molecular dynamics study of the pyrolysis mechanism of C6F12O
Published in Molecular Physics, 2021
Haoran Xing, Yuan Cheng, Song Lu, Neng Tao, Heping Zhang
As global environmental issues are becoming increasingly serious [1], ozone-depleting substances (ODSs) [2,3] containing chlorine and bromine including chlorofluorocarbons (CFCs), bromofluorocarbons (halons) and chlorofluorocarbons (HCFCs), once widely applied as fire suppressants and refrigerants, have been phased out under the Montreal Protocol (1987) and its subsequent adjustments and amendments. Great efforts have been made to identify the proper alternatives [2,4,5]. Hydrofluorocarbons (HFCs), as one of the most widely adopted substitutes, are not ODSs but greenhouse gases with a high global warming potential (GWP), which are restricted under the Kyoto Protocol (1997) and the Kigali Amendment to the Montreal Protocol (2016). According to the Paris Agreement (2016), which is committed to maintaining the global temperature rise within 2°C, many greenhouse gas substitutes of ODSs applied today are scheduled to be phased out [6]. The identification of suitable substitutes with negligible environmental impacts is of great significance to the industry.
Theoretical study of R32 to replace R410A in variable refrigerant flow systems
Published in International Journal of Ambient Energy, 2018
Canberk Yıldırım, Derya Burcu Özkan, Cenk Onan
Refrigerants which have been used in the heating, ventilating and air conditioning (HVAC) industry can be investigated under three categories, namely chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). CFC refrigerants cause the greatest damage than others on the ozone layer. Therefore CFC refrigerants can sustain their activity range from 75 to 120 years in soil by preserving their chemical structure. They have relatively high global warming potential (GWP) values. In addition, CFCs have high ozone depletion potential (ODP). Like CFCs, HCFCs also can react with the ozone layer as they contain chlorine. Since HCFCs contain hydrogen, their chemical stability is very poor. They cannot survive in the atmosphere without degeneration. Although HCFC refrigerants’ ODP value is very low, in other words they have low negative impact on the ozone layer, these refrigerants affect global warming very little (Koyun, Koyun, and Acar 2005). R410A, a HFC group refrigerant which has been widely used in residential heating and cooling systems, will be phased out due to its high GWP. Research efforts have been made to search for a substitute that has lower GWP and is as efficient as R410A.