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Increase Cooling- a hypothetical situation

kapilamuni on Tue October 11, 2011 7:14 AM User is offline

Refrigerant Type: R134a
Country of Origin: Sri Lanka


I noted the following from this site.

R-134a pressure Relationship

Pressures shown in the charts are provided as a general guide and may not represent your exact readings. Ambient temperature is measured 2 inches in front of the condenser.

Low Side Readings(PSI) Evaporator Temperature (Fahrenheit) High Side Readings (PSI) Ambient Temperature (Fahrenheit)
16-29 33-50 115-200 70-80
19-39 33-60 140-235 80-90
25-43 40-65 165-270 90-100
37-51 48-65 210-310 100-110

Now my question is
How do u obtain around 35F at the evaporator if the amb temp is around 100F, provided the vehicles AC system is functioning normal.?

what are things to be done ? Or is it just impossible to have evap temp at 33F when amb.temp @100F?



NickD on Tue October 11, 2011 8:11 AM User is offline

Typical readings for a CCOT system, a dirt cheap system using a cycling switch that actually doesn't cycle when it gets hot outside. Some improvements are made with a TXV system, but the really great systems used a TXV with a POE valve that was considered too expensive by most automotive manufacturers. So lucky to get a 65*F vent temperature in a 100*F ambient.

The newer variable displacement compressors are simple and do a far better job, the hotter the ambient the cooler the vent temperatures.

Color of your vehicle also makes a huge difference can be a 80*F difference between a black vehicle and a white one, black being much hotter. Read recently the most popular color was a almost black dark green, may be pretty but certainly not practical. But the solution to this is simple, just drive at night.

mk378 on Tue October 11, 2011 9:24 AM User is offline

For any given system, reduce the evaporator airflow and evaporator temperature will drop. The system can sustain a larger temperature difference with less BTU transfer. I don't think that is the question you were asking though.

kapilamuni on Tue October 11, 2011 9:56 AM User is offline

thanks guys. under that context,
What can I do with My TOYOTA tercel (diesel) with TV10EC- DENSO compressor?


NickD on Tue October 11, 2011 10:59 AM User is offline

In my travels, Toyota makes completely different vehicles for each different country than what they make for the USA. So kind of dead lost on this subject without having that vehicle in my hands.

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