Identifying the foremost refrigerant f-gases for vapor-compression cooling technologies

Fluorinated gases (f-gases) used for refrigeration have a global warming potential as high as 12,000 kgCO2-eq (for e.g., HFC-23). These are key to climate mitigation discussion as f-gases are critical to delivering the surging demand for air conditioners which is expected to triple by 2050 and are targeted by international policy agreements such as the Montreal Protocol and Kigali Amendment. Given their increased use as cooling demand sores, can we identify the climate-optimum f-gas for use in cooling technologies? This paper examines the metrics used to account for the carbon footprint of f-gases which are used as refrigerants for cooling. F-gases exacerbate atmospheric warming when leaked from cooling equipment, or during other phases of their life cycle. Thus far, the way these gases impact global warming is mostly reported based on their CO2-equivalent emissions with a time horizon of 100 years. However, the problem is that f-gases have significantly different lifespans and the Global Warming Potential (GWP) of 100 years metric does not account for these variations. We address this with a critical review of the available metrics for carbon foot-printing of f-gases and present a gap analysis between the existing carbon foot printing metrics and the need to better understand warming from fgases. Next, we exemplify the application of the incumbent metric (GWP100) in the estimation of emission by using an atmospheric model, whose preliminary results show the challenges that current metrics pose. The model shows profiles of atmospheric concentration, radiative forcing, and temperature, after three set scenarios in the release of an illustrative f-gas (|HFC-134a). Scenarios A models the response to a positive step change in emissions, while Scenario B is the inverse. Scenario C models a reduction of 85% by 2036 of emissions according to targets for high-emitting countries set in the Kigali Amendment. The results compare the atmospheric contributions of set emissions of HFC-134a to its CO2 equivalent-emissions (using GWP100). The paper offers insights into which metric can identify the best f-gas in terms of reducing global warming in a rapid timeframe, and its policy implications