Development and application of a life cycle greenhouse gas emission analysis model for mobile air conditioning systems

Abstract

Mobile air conditioning (MAC) is potentially a huge source of greenhouse gas (GHG) emissions in China from a life cycle (LC) perspective as the vehicle population increases in the future. The MAC-GHG-LCA model is developed to calculate LC GHG emissions from MAC systems, covering life-span refrigerant leakage (direct emissions) and emissions caused by energy use in MAC system production and operation (indirect emissions). Using R152a and R1234yf as alternative refrigerants instead of R134a in MAC systems can decrease LC GHG emissions by 22–32% and 17–29%, respectively. Their GHG reduction benefits mainly result from their lower global warming potential (GWP) values though the indirect emissions are only slight lower or even higher than R134a. Using R744 can offer reduction in 2050 though it will cause an increase of 20% in 2020. Total LC GHG emissions from MAC systems of the whole light duty vehicle (LDV) fleet in China will be 159 million tonnes of CO2-equivalent in 2050 in the scenario where R134a will be the only refrigerant adopted, about 3 times that in 2015. It is found that alternative low-GWP refrigerants can help reduce LC GHG emissions from MAC systems effectively. The shift from conventional cooling and heating technology to advanced heat pump technology in electric vehicles (EVs) can reduce electricity use in MAC system operation and reduce LC GHG emissions from the MAC systems in EVs.