For research purposes. 1234YF is insanely more expensive than 134. But can a 1234YF system, safety and efficiency, run 134? Again, for research purposes only. I know legally, and “environmentally” it can’t be done.
Illegal. Even if you could do it, the air conditioner is run by computer, which would defeat the purpose. R-134a and R-1234YF are very different chemicals, with different specific heat capacities. This is key for designing an air conditioner. Your R-1234YF based condenser and evaporator will be inefficient, or not function at all.
it's illegal. End of story.
FYI, valves, fitting and pressure settings are different. You cannot mix them.
Illegal. Various internet sources claim it will work, but aside from legality if you think that refrigerant is expensive cost out replacing your compressor and possibly other components if the research experiment goes horribly wrong. Best thing to do is fix any leaks first and stick with R1234yf.
