What the study found
R440A was the most energy and exergy efficient refrigerant among the alternatives compared for automobile air conditioning systems in cooling mode. In the TEWI (total equivalent warming impact, a measure combining direct and indirect warming effects) comparisons, R1234ze(e) had the lowest value for gasoline-powered vehicles.
Why the authors say this matters
The study suggests that comparing both thermodynamic performance and TEWI can help identify refrigerants that perform better in automotive air conditioning systems while also affecting warming impact. The authors conclude that the results provide a basis for judging the relative performance of the tested refrigerants.
What the researchers tested
The researchers compared refrigerants R1234yf, R1234ze(e), R152a, R430A, and R440A as alternatives to R134a in automobile air conditioning systems operated in cooling mode. They evaluated energetic and exergetic performance at typical evaporating and condensing temperatures for a 4 kW cooling capacity, and calculated direct and indirect TEWI for automobiles using gasoline, diesel fuel, and LPG.
What worked and what didn't
R1234yf and R1234ze(e) had 4.11% and 0.16% lower coefficient of performance (COP) than R134a, respectively. R152a, R430A, and R440A had 3.20%, 1.52%, and 4.46% higher COP, respectively, and R440A also ranked highest in exergetic efficiency. For gasoline use, R134a had the highest TEWI at 5834 equivalent kg CO2, while R1234ze(e) had the lowest at 2857 equivalent kg CO2; in the TEWI ranking, R134a was followed by R440A, R152a, R430A, R1234yf, and R1234ze(e). Diesel results were described as quite close to the gasoline case, and LPG cases were 9–18% lower than gasoline and diesel for all refrigerants.
What to keep in mind
The abstract reports results for a specific cooling-mode automotive air conditioning setup, a 4 kW cooling capacity, and typical evaporating and condensing temperatures. It does not describe other operating conditions, broader vehicle types, or additional limitations beyond this scope.
Key points
- R440A showed the highest coefficient of performance and the highest exergetic efficiency among the tested refrigerants.
- R1234yf and R1234ze(e) had slightly lower COP than R134a, while R152a, R430A, and R440A had higher COP.
- For gasoline-powered vehicles, R134a had the highest TEWI and R1234ze(e) had the lowest TEWI.
- Diesel TEWI results were reported as quite close to the gasoline case.
- For LPG vehicles, TEWI from the air conditioning system was 9–18% lower than for gasoline and diesel cases.
Disclosure
- Research title:
- R440A showed the best energy and exergy performance among tested refrigerants
- Authors:
- Murat Hoşöz, Eren Kabak
- Institutions:
- Kocaeli Üniversitesi
- Publication date:
- 2026-03-08
- OpenAlex record:
- View
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