UNEP Workshop on HFC Management Bangkok, Thailand 20, 21 April 2015 Technical Issues: Session 3 Challenges and Opportunities in addressing high GWP HFC’s in Mobile Air Conditioning (MAC) Options for Existing Systems / Equipment (Drop in / Retrofit) SH Kapoor Technical Chief (Climate Control) TATA Motors Limited, India Email: sh_kapoor@tatamotors.com

Low GWP Refrigerants: Drop In / Retrofit Options? Refrigerant Parameters for Operating Limits: 0°C Evaporating Temperature and 55°C Condensing Temperature Parameter HFC134a (GWP=1430) HFO1234yf (GWP=4) HFC152 (GWP=124) R744 (GWP=1) Suction Pressure (bar-abs) 2.9 3.2 2.6 34.9 Discharge Pressure (bar-abs) 14.9 14.6 13.3 115 Pressure Ratio 5.1 4.6 3.3 Enthalpy of Vaporization (kJ/kg) 198.6 163.3 307.1 231.3 Vapour Specific Volume (m3/kg) 0.069 0.057 0.119 0.0103 R1234 yf R134a Cooling Performance cannot be matched with R1234yf as a ‘Drop In’ Equivalent performance and durability requirements need to be met with significant re-engineering of MAC system components R152a Superior Cooling Performance can be attained with R152a; cannot be ‘Drop In’ due to flammability risk in case of leak (cab/engine) Potential Secondary Loop refrigerant with down sized MAC system components for matching R134a Cooling Performance R744 R134a Cooling Performance cannot be matched with R744 at higher ambient temperatures (Tc=31°C) All MAC system components require significant re-engineering due to very high system pressures and hence ‘Drop In’ is not a feasible option

Secondary Loop MAC: R152a, R1234yf Parameter Opportunity Challenge Design With proper engineering design, freeze protection and optimization, secondary loop MAC’s are suitable for all climates Complexity of integration / packaging of the additional components (small cars) Added components, increased weight Performance Cabin cooling not compromised during extended idle and long idle stops (stop / start traffic) Homogeneity of air temperatures across cooling coil due to absence of phase change Minimizes fluctuations in vent outlet and cabin temperature Reduce engine load during acceleration by switching off compressor (fuel economy) Timing powered cooling – switch on compressor when engine is at high energy efficiency Reduced MAC system noise transmitted from thermostatic expansion valve (TXV) inside passenger cabin Increased time to ‘pull down’ temperature to comfortable levels due to thermal inertia of coolant Development and integration of Engine Management System (EMS) Coolant pump power consumption Refrigerant Circuit Absence of oil trapping issues in dual AC MAC systems particularly when rear unit is turned off

Secondary Loop MAC: R152a, R1234yf Parameter Opportunity Challenge Material Cost Reduced refrigerant charge offsets cost of additional components even for dual AC MAC systems (multiple cooling points) Reduced frequency of refrigerant recharges over a vehicles service and maintenance life (lower ownership costs) Environment Use of environment friendly low GWP refrigerant R152a / R1234yf Reduced refrigerant charge and life cycle GHG emissions Safety Reduced refrigerant charge lowers fire risk Refrigerant separated from passenger compartment Deploy refrigerant leak sensor and relief valves for quick release of refrigerant to atmosphere (thru wheel arch) Charged components placed in wind stream and away from ignition sources

Summary: Drop in / Retrofit Refrigerant Options for Existing Systems / Equipment HFO1234yf is gaining acceptance as an alternate MAC refrigerant option due to its low GWP of 4 but is mildly flammable HFO1234yf as a drop in refrigerant for a car already in service poses the challenge of deterioration in cooling performance and risk of cross contamination with existing PAG oil Not all compressors are available with PAG oil compatible with HFC134a and HFO1234yf This can lead to compressor durability issues and hence drop in is not recommended

Summary: Drop in / Retrofit Refrigerant Options for Existing Systems / Equipment HFC152a is a low GWP, slightly flammable refrigerant with superior properties and high potential of downsizing MAC system components like compressor and condenser The flammability risk associated with HFC152a and HFO1234yf can be mitigated by reducing the refrigerant charge, deployment of a Secondary Loop (SL) and use of leak sensors and relief valves The SL – MAC in combination with power train technologies has a high potential of improving overall energy efficiency and reducing carbon footprint To evaluate the opportunity of using SL – MAC with HFC152a and HFO1234yf, understand the challenges related to cooling performance, safety, power train technology and cost impact, a demonstrator car project needs to be initiated by relevant stakeholders

End of Report Thank You for your Attention! Questions

MAC Refrigerants: Past, Present and Future Status Phased Out Current Future: Potential Alternatives Parameter R12 (CFC) R22 (HCFC) Building Air Conditioning R134a (HFC) R1234 yf (HFO) R152a (HFC) R744 Bonding IUPAC Name Dichloro Difluoro Methane Chloro Difluoro Methane 1,1,1,2 – Tetra Fluoro Ethane 2,3,3,3 – Tetra Fluoro Propene 1,1 – Difluoro Carbon Dioxide ODP 1 (2 Chlorine Atoms) 0.05 (1 Chlorine Atom) GWP (100yr) (IPCC AR4) 10,900 1810 1430 (4 Fluorine Atoms) 4 124 (2 Fluorine Atoms) 1 Atmospheric Lifetime 100 years 12 years 14 years 0.03 years (due to weaker double bond) 1.4 years >100 years Flammability (ASHRAE) A1 A2 L (Mildly) A2 (Slightly) Critical Temperature 111.9°C 96.14 101.06°C 92.42°C 113.26°C 31.04°C Normal Boiling Point -29.8°C -40.7°C -26.3°C -29.4°C -25°C -78°C H F C C Cl F C Cl F H O C A1 : No flame propagation A2 : Slightly flammable- Lower flammability limit @ 60°C: > 100 g/m3 or Heat of Combustion < 19 Mega J/kg A2L : Mildly flammable-Lower flammability limit @ 60°C: > 100 g/m3 and Heat of Combustion < 19 Mega J/kg With Maximum Burning Velocity < 10 cm/s