What is the function of the evaporator?
4 Answers
Here is a related introduction about the automotive evaporator: 1. The automotive evaporator is a component of the air conditioning system. 2. Its function is to allow low-temperature condensed gas to pass through the evaporator, exchange heat with the outside air, liquefy and absorb heat, thereby achieving a cooling effect. 3. The evaporator is a heat exchanger where high-pressure liquid refrigerant enters the evaporator through the expansion valve. Due to the atomization effect of the expansion valve, the liquid refrigerant turns into a mist, which then changes into a gaseous state under low-pressure conditions. 4. Because this transformation process absorbs heat, the evaporator becomes relatively cold at this stage. When air passes through it, it turns into cool air, achieving the cooling effect. 5. The layout of the air conditioning assembly varies in different vehicles; in passenger cars, it is generally located inside the CPM, with the evaporator placed behind the air filter. Two pipes are connected to the side of the evaporator, linking it to the expansion valve.
The evaporator is essentially the 'heat absorption converter' in the air conditioning system, functioning similarly to the freezer compartment in a household refrigerator. Its job is straightforward: when liquid refrigerant sprays into the evaporator from the expansion valve and suddenly releases pressure, this physical reaction instantly absorbs a large amount of heat from the surroundings. The cool air you feel blowing in the car is the result of this heat absorption and conversion. I've seen many car owners neglect regular cleaning, leading to accumulated condensation and unpleasant odors. Those dense aluminum fins on the evaporator housing are experts at trapping dirt and grime. If your AC emits a musty smell, chances are the evaporator has mold growth.
When it comes to the hardest-working components in a car's air conditioning system, the evaporator definitely ranks in the top three. Hidden behind the dashboard, it silently serves as the 'dehumidifying and cooling worker.' High-temperature air passes over the cold aluminum fins of the evaporator, not only causing a sharp drop in temperature but also condensing moisture into water droplets that are drained out of the car. Last week, while helping a friend troubleshoot an AC odor issue, we discovered that the evaporator's drain tube was clogged with leaves, causing water to overflow into the cabin air filter. So, poor cooling performance isn't always due to low refrigerant—a blocked drain tube can also make the AC stop working.
Hearing the blower humming when the AC is on? That's it pushing hot air toward the evaporator. The liquid refrigerant evaporates into gas within the evaporator's intricate piping, a process akin to forming an icy film on the pipe surfaces. As air passes through the gaps between the aluminum fins coated with ice, its temperature plummets, delivering that refreshing coolness to your face. This conversion process demands absolute airtightness—even a minor refrigerant leak drastically reduces cooling efficiency. Recently, a car owner kept recharging the refrigerant without achieving coolness, only to discover upon disassembly that the evaporator had corroded, leaving pinhole-sized leaks.
