A/C Chilling Effect

To understand the chilling effect of refrigerant, open the nozzle of a pressurized can of liquid (butane for example). As the liquid is changed to a gas, energy is absorbed, and there is a chilling effect.
The A/C compressor pressurizes the gas (freon). The high pressure gas will liquefy when it can release it's energy. The condenser (looks like a radiator) changes the gas to a liquid. An expansion valve or orifice tube is then used to control the amount of high pressure liquid to the accumulator (filter/dryer), which is mounted in the low pressure side, and prevents the compressor from receiving liquid. Only a small amount of high pressure liquid goes into the evaporator core under the dash (looks like a heater core ). The compressor is sucking on the other side of the evaporator core causing a low pressure area in the core. When the refrigerant enters the core it vaporizes and cools, allowing the blower motor air to be cooled in the process. The core is subject to freezing from condensation, so a compressor cycling switch is used to help control the temperature. The switch mounted in the low side, on the accumulator (filter/dryer), will shut down the system altogether when freon pressure falls too low, protecting the components from damage. The system can also purge itself at the compressor valve (pop-off) if pressure rises too high.

This article is for informational purposes. Refrigerant is under high pressure, and can freeze skin, and hurt the eyes. Some information has been reproduced from text for ease of understanding {for all you lawyers ;~} Feedback is welcome. Have your system diagnosed by a certified a/c specialist when needed.