What is air conditioner evaporator?

Source:
http://www.central-air-conditioner-and-refrigeration.com/air_conditioner_evaporator.html

Air conditioner evaporator is a
heat exchange. It takes in low
temperature, low-pressure
liquid refrigerant from the
expansion device and changes
it into low-pressure, low temperature vapor refrigerant.

Evaporator coil is the components that add heat to the air conditioner units.

* Notes: refrigeration is the
process of removing heat from
one area where it is
undesirable to an area where
it is not significant. For this
process to work heat has to flow from one area (medium)
to another.
To make heat flows, one of the
mediums has to be at a higher
temperature. Since, heat
always flows from a high
intensity to a low intensity.

Types of air conditioner
evaporator:

Director-expansion or Air-

cooled Evaporator
 1. Flooded evaporators

How does air conditioning
evaporator works?
Air conditioning evaporator
works by absorb heat from the
area (medium) that need to be
cooled. It does that by
maintaining the evaporator
coil at low temperature and pressure than the surrounding
air.
Since, the AC evaporator coil
contains refrigerant that
absorbs heat from the
surrounding air, the refrigerant
temperature must be lower
than the air.
The expansion device provides
a pressure reduces between
the high side and the low side
of the system, the saturation
temperature of the refrigerant
entering the air conditioning evaporator is lower than the
medium to be cooled.
One of the characteristic of a ac refrigerant is that as the pressure is reduced the boiling
point is also reduced.
Therefore, as the pressure is
reduced through the expansion
device so is the point at which
it will boil and become a vapor.
As the warm air from the
space passes over the
evaporator coil, it gives up its
heat to the lower temperature
liquid/vapor mixture passing
through the evaporator. As the liquid refrigerant absorbs this
heat it boils changing from the
liquid state to the vapor state.

The amount of heat the air conditioner evaporator absorbs must equal the amount of heat it lost

For instance, if the air
conditioning evaporator gives
up 100 Btu’ s of heat to the surrounding hot air, then the
refrigerant within the air
conditioning evaporator coil
must gain 100 Btu’ s of heat.
The amount of liquid entering
the evaporator must be
enough, so by the time it
reaches the end of the
evaporator. It will be
completely boiled to the vapor state.
There must be enough air
flows across the AC evaporator
coil to provides heat to the
refrigerant in the evaporator
coil. This is just a safety way to
ensure the air conditioner compressor doesn’ t have the liquid refrigerant entering it.

Air conditioning evaporator
picture above tells us what
happen to the evaporator coil.
The air conditioning
evaporator coil absorbs heat
into the refrigerant from the
warmer air passing over the
surface of the evaporator coil.
The heat absorbed causes the liquid refrigerant to boil,
changing it from a liquid state
to a vapor state.
Types of air conditioning
evaporator coil:

Bare-tube coils

1. Finned-tube coils
2. Flat-plate coils
central air conditioner parts
Air Conditioner Condenser
Air Conditioner Compressors
Air Conditioner expansion
valve