Impact Analysis of an Alternate Environment Friendly Refrigerant Deployed in the Air Conditioning System of IC Engine and Electric Vehicles 2023-28-0038

Today, most vehicles in developing countries are equipped with air conditioning systems that work with Hydro-Fluoro-Carbons (HFC) based refrigerants. These refrigerants are potential greenhouse gases with a high global warming potential (GWP) that adversely impact the environment. Without the rapid phasedown of HFCs under the Kigali Amendment to the Montreal Protocol and other actions, Earth will soon pass climate tipping points that will be irreversible within human time dimensions. Up to half of national HFC use and emissions are for the manufacture and service of mobile air conditioning (MAC). Vehicle manufacturers supplying markets in non-Article 5 Parties have transitioned from HFC-134a (ozone-safe, GWP = 1400; TFA emissions) to Hydro-Fluoro-Olefin, HFO-1234yf (ozone-safe, GWP < 1; TFA emissions) due to comparable thermodynamic properties. However, the transition towards the phasing down of HFCs across all sectors is just beginning for Article 5 markets. Patents on R-1234yf will soon expire, just as scarcity is likely to drive the price of R-134a to historic highs.

This work consists of two case studies, specific to an Internal Combustion Engine (ICE) and an Electric Vehicle (EV). Two different refrigeration system architectures are examined. Both the shortlisted vehicles have different and complex AC system architectures. Complex AC system architectures are selected in this study with the objective of understanding and deploying the learnings in vehicles with less complex and simpler AC system architectures. The ICE vehicle selected for the study has a dual AC configuration with two cooling points (front and rear), using DX architecture. In the EV, an architecture similar to that of the ICE vehicle is deployed for cabin cooling, but unlike the ICE vehicle, it has a secondary coolant-based loop provisioned for battery thermal management. For this study, the baseline HFC-134a refrigerant is replaced by a ‘drop-in’ alternate low-GWP HFO-1234yf refrigerant in both vehicles.

This study focuses on cooling performance evaluation with existing HFC refrigerant and proposed HFO refrigerant for both AC system architectures, gap identification, and proposing common and unique solutions for bridging the performance gaps.