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Li et al. Carbon Footprints 2024;3:6 https://dx.doi.org/10.20517/cf.2023.54 Page 11 of 14

However, this study also has some limitations. For instance, the LCA model used in this study primarily
focuses on analyzing the impact of different low-GWP refrigerant options on the carbon emissions of
electric vehicle air conditioning. Nevertheless, it is important to note that, unlike the indirect emissions
generated by the fuel consumption of air conditioning in traditional ICEV, the indirect emissions of EV air
conditioning are tied to the electricity consumption of vehicle batteries. Therefore, the CEF (Carbon
Emission Factor) of the power grid will significantly influence the carbon emissions of electric vehicle air
conditioning. Considering the continuous increase in the installed capacity of green energy sources in
China, which is leading to a decreasing trend of CEF over time, the predicted carbon emissions of the MAC
fleet in Figure 4 of this paper should also be appropriately adjusted. Hence, it is more reasonable to
supplement the prediction of the power generation technology trajectory in China’s electricity system,
thereby obtaining a more accurate calculation of GHG emissions within the carbon accounting boundary
for automotive air conditioning fleet predictions.

CONCLUSION
The primary conclusions of this paper are as follows:

1. At the carbon accounting boundary of electric vehicle air conditioning products, the use of heat pump
technology can achieve a carbon reduction of 23% to 45% compared to PTC heating. Among several heat
pump air conditioning systems that use low-GWP refrigerants as alternatives to R134a, the R290 system
exhibits the lowest life cycle carbon emissions, approximately 3,939.7 kg CO -eq. The ranking of LCA
2
results for electric vehicle air conditioning under different refrigerant options is R290 < R1234yf < R744 <
R134a < AC + PTC.

2. At the carbon accounting boundary of the automotive air conditioning fleet, the carbon emissions of
China’s automotive air conditioning fleet in 2022 amount to approximately 162 million tons of CO -eq,
2
accounting for about 1.17% of the national carbon emissions and 6.16% of the carbon emissions caused by
road transportation. Emissions reduction in the automotive air conditioning industry is of significant
importance for national urban carbon neutrality. The future carbon emissions of the automotive air
conditioning fleet will increase with the growth of the vehicle fleet until around 2040-2045, when it is
expected to decline gradually. At the fleet level, the LCA of the R290 route has the comparatively lowest
carbon emissions, and replacing R134a with R290 is estimated to achieve a cumulative emission reduction
of approximately 388 million tons of CO -eq.
2

3. The LCCA results for electric vehicle air conditioning using different refrigerants indicate that the AC +
PTC technology, although exhibiting the comparatively lowest CapEx, incurs an extremely high OpEx and
thus has poor economic viability. While the R744 heat pump exhibits strong low-temperature heating
capabilities, the predominance of temperate and subtropical climates in China may limit its economic
viability in most cities. Among the refrigerant options studied in this paper, the current industry-standard
R134a heat pump has a life cycle NPV cost of approximately 11,500 CNY, with the R290 system exhibiting
the comparatively lowest NPV cost under national average conditions. Combining the analyses of LCA and
LCCA, this paper suggests that the R290 heat pump has an excellent carbon emission reduction potential
and also cost-effectiveness in most Chinese cities, making it a promising choice for refrigerant replacement
in electric vehicle air conditioning.

4. Ideally, selecting low-GWP refrigerants and air conditioning technologies suitable for local conditions is a
suggested rational approach. For instance, the economic benefits of low-temperature heat pumps are well
demonstrated in cold climates. In some cold cities such as Harbin, the ROI of the R744 system relative to