### Applications  
F-gases are widely used for several industrial and commercial applications, mainly as refrigerants in cooling systems, as blowing agents in the manufacturing of organic and inorganic foams and materials, in the manufacturing of electronics, and as part of aerosols, fire extinguishers, and solvents. The most important HFCs used today include the HFC R-134a (GWP 1430) and the HFC blends R-404A (GWP 3922) and R-410A (GWP 2088) [7]. R-404A (GWP 3922) is a blend of R-125 (GWP 3170), R-134a (GWP 1430) and R-143a (GWP 4800), and R-410A (GWP 2088) is a blend of R-32 (GWP 677) and R-125 (GWP 3170). Almost half of F-gas emissions and about 86% of the HFC consumption (in GWP) are due to cooling and refrigeration systems [8]. The dependence on these systems, and therefore on F-gases, is increasing worldwide since societies depend largely on: (i) industrial and commercial refrigeration for the functioning of food, chemical, pharmaceutical and other industries, and of the retail sector (for example, supermarkets and restaurants); (ii) domestic refrigerators and freezers in houses and offices; (iii) refrigerator containers for transport; and (iv) stationary and mobile air conditioning to cool personal and commercial transportation vehicles, houses, offices and other buildings. Most systems rely on high GWP F-gases, such as the CFC R-12 (GWP 10,200), the HFC R-134a (GWP 1430), and the HFC blends R-404A (GWP 3922) and R-507A (GWP 3985), and have high leakage rates [9]. These direct emissions of GHGs, together with the high electricity demands (almost 17% of global electricity use) that represent indirect GHG emissions, are responsible for making the cooling and refrigeration sector one of the main contributors to global warming [9]. Today, almost 4 billion pieces of cooling equipment are estimated to be in use globally. This number may rise up to 14 billion by 2050 as a consequence of the rise in global temperatures and of the increasing capacity of the populations in developing countries to have access to cooling equipment [9]. The global energy demand for building cooling more than tripled between 1990 and 2016 and the installed capacity is predicted to rise from 11,670 GW in 2016 to over 36,500 GW in 2050 [9]. Without the international agreements and the application of legislation at international and national levels, the direct and indirect emissions from the air conditioning and refrigeration sectors are projected to rise at least 90% from 2017 levels by 2050 [9,10]. The increased utilization of F-gases for cooling leads to global warming, creating a feedback loop with dangerous consequences. Buildings last for several decades and therefore changes in the climate (i.e., increase in temperature and changes in other factors such as wind, solar radiation, and humidity) greatly influence their energy profile over the years. Several studies have addressed the impact of climate change on buildings' energy use, using different methods and climate models [11-16]. While the impacts will be different according to the geographic location, for all regions a decrease in energy use for heating and an increase in energy use for cooling are expected. Since the dependence on refrigeration and cooling will continue to increase in the foreseeable future, it is vital to switch to low GWP refrigerants. In emergent economies, the increasing demand for air conditioning systems is not being accompanied by the utilization of environmentally friendly alternatives, and high GWP and ozone-depleting refrigerants, such as R-22 (GWP 1760), still dominate the markets [17]. In the markets where R-22 (GWP 1760) is being phased out, the high GWP R-410A (GWP 2088) is the most used refrigerant [17]. The refrigerant R-410A (GWP 2088) is currently being phased out under the current EU legislation, as will be discussed in Section 2 (HFC Phase Down), and the transition to new more environmentally friendly alternatives is taking place. The market of the air conditioning systems in cars and other transportation vehicles is expanding largely.