The evaporator works the opposite of the condenser, here refrigerant liquid is converted to gas, absorbing heat from the air in the compartment. When the liquid refrigerant reaches the evaporator its pressure has been reduced, dissipating its heat content and making it much cooler than the fan air flowing around it.
As refrigerant travels through the evaporator, it absorbs heat from the air. As it absorbs heat, it vaporizes. If the system operates according to design, the refrigerant will be 100% vapor as it nears the exit of the evaporator. Before leaving the evaporator, the vapor continues absorbing heat, becoming superheated.
Since refrigerant comes out of the evaporator as a superheated vapor, it will enter the compressor as a superheated vapor. The compressor's job is to increase the pressure of the refrigerant. Recall that as pressure increases, temperature increases. This is exactly what the compressor does.
In the evaporator, refrigerant absorbs heat from the indoor air to change state from liquid to vapor. So, when the refrigerant leaves the evaporator, it is fully in vapor state (low pressure).
The evaporator functions by allowing the refrigerant to evaporate and expand in a controlled environment. As the liquid refrigerant enters the evaporator, it encounters low pressure, which causes it to vaporize and absorb heat from the surrounding air or medium that needs cooling.
After full evaporation, when 100% of the refrigerant has become saturated vapor (c), the temperature of the vapor will start to increase, i.e. the vapor will become superheated. The refrigerant flow leaving the evaporator will be 100% superheated vapor (d).
A common misconception is that Freon evaporates. It is not the Freon that evaporates but the moisture in the air that will do so. The beads of water go back and forth between the liquid and gaseous forms when there is a temperature difference outside and inside.
Refrigerant can shift easily between liquid and gas states, which makes it ideal for ACs since it doesn't take significant amounts of energy to cause the phase shift. Refrigerant starts inside the compressor, where the reduction of volume turns it into a high pressure gas about 150°F.
The purge unit is located at the top of the condenser coils. The refrigerant is sucked into the purge unit from the top of the condenser. The refrigerant free from air and moisture is then sent to the evaporator through the expansion valve.
If the evaporator fan motor is broken, then cool air won't circulate properly. Sometimes you wind up with a freezer that's still pretty cold—because that's near where the coils are—but a fresh food compartment that isn't cold at all because the cool air isn't getting pushed there.
Upon entering the evaporator, the liquid refrigerant's temperature is between 40° and 50°F; and without changing its temperature; it absorbs heat as it changes state from a liquid to a vapor. The heat comes from the warm, moist room air blown across the evaporator coil.
For an air conditioning system to operate with economy, the refrigerant must be used repeatedly. For this reason, all air conditioners use the same cycle of compression, condensation, expansion, and evaporation in a closed circuit.
When the AC is turned off, some part of the refrigerant condenses in the coolest part, while the rest exists as gas in the coils of the AC unit.
After picking up heat indoors, the hot, low pressure refrigerant gas leaves the evaporator coil and travels via copper pipes to the outdoor unit's compressor, which raises the refrigerant's pressure and temperature. Now a high pressure gas, the refrigerant enters the condenser coil.
Since the temperature of the evaporator coils is extremely cold, the temperature of the incoming air will start to decrease as it's circulated through the coils. The coils are designed to absorb heat energy and transform the air in the system from a warm temperature to a cold temperature.
The condenser removes heat from the hot refrigerant vapor gas vapor until it condenses into a saturated liquid state, a.k.a. condensation. After condensing, the refrigerant is a high-pressure, low-temperature liquid, at which point it's routed to the loop's expansion device.
As it cools, the oxide flakes off to form “scale,” which is then carried by the refrigerant throughout the system, contaminating filter driers, compressor oils, and valves. This build-up of oxide jeopardizes the efficiency and life of the equipment.
Without the refrigerant, there's no way to remove heat from your home. The system might turn on and run. There will be air coming out of the vents. But the air won't be cold at all.
In an HVAC system, refrigerant is found inside the copper coils and runs through several components such as the condenser, compressor, evaporator, and expansion valve. During the refrigeration cycle, the refrigerant absorbs heat energy from the refrigerated space and then transfers it outside through a condenser coil.
The evaporator works the opposite of the condenser, here refrigerant liquid is converted to gas, absorbing heat from the air in the compartment. When the liquid refrigerant reaches the evaporator its pressure has been reduced, dissipating its heat content and making it much cooler than the fan air flowing around it.
If your air conditioner were filled with water, it would take a huge amount of energy to move heat from inside your home to the outside. Water just takes too much pressure, time, and energy to compress to the point where it will absorb heat properly. Refrigerant does this job much better.
It is likely that the sweet smell you are noticing is a Freon (for older units) or Puron (for newer AC units) leak. These products have a sweet chloroform smell and when it leaks, it can fill the air with this sweet scent. You should have a professional inspect your air conditioner to determine if this is the cause.
Refrigerant is a working chemical that runs through your car's A/C system in either a gaseous or liquid form. Causes of refrigerant leaks in your vehicle include physical damage, wear and tear over time, and escaping refrigerant even without a leak.
Since refrigerant often appears as a gas, this can leave you wondering, “Does Freon leak as a liquid?” It is possible, and if you see refrigerant in its liquid state, it appears clear or slightly pale yellow. These signs are your cues to call the professionals before more damage unfolds.
Theoretically, Freon can last forever. It is not burned up like fuel. When an air conditioning system is in top shape, the refrigerant will be continually recycled within a closed system, to cool your home.