One labstudy on r134 "drop-ins" also available from Spain.
https://www.researchgate.net/publica...a_alternatives
The indicated pressures (MPa) in the test are probably misleading (bar OK?).
However ,its obvious r290 and r152a superior to r134a and ... to newcomer r1234yf, which is (of utmost peculiar reasons) chosen as the winner refrigerant over r134a in the new car segment.
Earlier for ex. VW-was stronly against r1234yf but today the very same refrigerant is
as a default in their new vehicles ... odd!
https://refrigeranthq.com/germany-au...gainst-1234yf/