Quote: Originally Posted by Eric Eliel Huh? The electrical fan in front of the radiator starts on its own when the temperature switch is triggered by the heat sensor in the receiver/dryer. You can't turn it on manually. My idea would be to design a circuit that would starting the condensor fan cooling process immediately but temporarily to get the condensor cooling faster. That is my point. If the refrigerant is not hotter than the ambient air, no amount of airflow will cool it. The hotter the refrigerant, the more efficient the transfer of heat to the air through the condenser. If you want the fan to come on earlier, get a switch that engages the fan at a lower refrigerant temperature. There really isn't a reason to engage the electric fan if the refrigerant temperature is not hot and not under high pressure, unless you just want to waste energy and wear out your fan a lot quicker.

What I mean to say here, is that if the refrigerant is not hot yet is still a liquid, additional airflow will not help very much.

However, when you first start the system and the refrigerant is not even yet being introduced into the evaporator as a liquid, adding more airflow will not help AT ALL.

True, but the pressure and temperature will build in a few seconds, not minutes.

Hydrocarbon refrigerants have worked the best for me to improve on R-12. Better for the environment than R134A too.

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Ron Schroeder
'85 300 Turbo Diesel 2 tank WVO
'83 300 Turbo Diesel 2 tank WVO
Some former WVO vehicles since ~1980:
'83 Mercedes 240D
'80 Audi 4000D
'83 ISUZU Pup
'70 SAAB 99 with Kubota diesel
'76 Honda Civic with Kubota diesel
'86 Golf
Several diesel generators
All with 2 tank WVO conversion
LI NY

It would be best if the system were designed for HCs, but they do seem to work well in practice. From what I read, the system won't get as cold at idle as with R12, but people seem to be happy with the results.

I'm more worried about R744 (CO2) as a refrigerant to be adopted by car manufacturers and its inherent dangers due to extremely high pressures. HCs have shown enough promise that I would rather the manufacturers go that route. A properly-designed HC system would chill you out of the car at all speeds.