The document provides information about an air conditioner presentation given by Rupesh, a student in the ME 1 (8th Sem) class with Roll No. 21760. It discusses how air conditioners work by collecting hot air, processing it using a refrigerant and coils to release cool air. It explains the components of an air conditioner including the evaporator coil, compressor, condenser coil and expansion valve. It also describes the air conditioning cycle where a refrigerant undergoes phase changes from a gas to liquid and back to a gas to absorb and release heat from the air.

1. Maharshi Dayanand University
Presentation on air conditioner
Name – Rupesh
Class – ME 1
(8th Sem )
Roll No. - 21760

2. Air Conditioner
• An air conditioner in a room or a car works by absorbing hot air from a
particular room, processing it into itself with the help of a refrigerant and a series
of coils, and then releasing cool air into the same room where the hot air was
originally collected.
• The AC removes hot weather and makes you feel fresh, that too without any
sound, that is why the trend of AC has grown everywhere, and it is essential to
use because air conditioners have provided an excellent service in all weather.
Not only do they cool your home's interior air and create a comfortable
environment, but they also improve the air quality inside your house by making
it clean. Modern AC units are fitted out with washable or disposable filter media
that deject allergens and pollutants from circulating throughout your interior
spaces.

3. How Air Conditioner Works
• Air conditioning operates based on the principles of phase conversion, which is the
transformation of a material from one state (or phase) of matter to another, such as when a
material changes from a liquid to a gas. When a liquid to gas change occurs, the material absorbs
heat. Conversely, when the material changes from gas to liquid, it releases heat. An air
conditioner is basically a machine that forces phase conversion and uses the resulting heat
transfer principles to cool buildings.
• An air conditioner collects warm air from a given location, processes it with the help of a
refrigerant and a series of coils within it, and then releases the cold air to the place where the hot
air was initially collected. Virtually all air conditioners system works on this principle. Most of us
believe that an air conditioner produces fresh air with the help of machines installed inside it,
which can cause it to cool a room so quickly. Hence they say why it consumes so much
electricity. However, this is a delusion. The air conditioner is not a magic device as it follows a set
of physical and chemical phenomena to cool a place very effectively when you turn on an AC and
set your desired temperature around 20-25 degree, the thermostat installed in its senses that there
is a difference between the room air temperature and the temperature you choose.

4. This hot air is drawn from the base of the indoor unit through the grille; the air flows through
some of the pipes through which the refrigerant or the cooling fluid is leaking. The refrigerant
liquid absorbs heat and becomes hotter than before. In this way, how the weather is removed
from the air falling on the evaporating coil.
The evaporator coil not only absorbs heat but also expels moisture from the incoming air,
which helps reduce condensation from the room. This hot refrigerant gas is then passed to the
compressor located on the external unit in case of split AC. The compressor compresses the
cooling gas so that it heats up because compressing the gas raises its heat. This hot, high-
pressure gas then moves to the third section called a condenser.

5. Air Conditioner Components
Evaporator Coil
In a mini-split air conditioner, the evaporator coil is found in the indoor unit, while in a central
system, it is located in the air handler.
Refrigerant, which is flowing through the system, is cooled to a low temperature just before
entering the evaporator coils. As warm air from your home is drawn in your HVAC unit, it is
blown over the cool evaporator coils which extract the heat and cool the air down. Fans located
behind the evaporator coil then blow this cool air back inside, reducing your home temperature.
These coils are usually made out of copper but can also be made of steel or aluminum. Copper is
the preferred choice because it has better thermal conductivity, is easier to work with, and is
effortless to maintain.
Be sure to keep your coils clean, though, as over time, dirt and dust can build upon them and
reduce their efficiency. A build-up of this dust can also block the condensation drain and result in
refrigerant leaks. While it is protected by the air filter, yearly cleaning will help keep your
evaporator coils in the best condition.

6. Compressor
Perhaps the most important of all air conditioner components, the compressor is the workhorse
of air conditioning. For central and split systems, the compressor is located in the outdoor unit.
The majority of an air conditioner’s energy consumption is because of the compressor, and it is
generally the most expensive part of the system.
The purpose of the compressor is, as the name suggests, to compress the refrigerant, which is a
warm vapor as it reached the compressor,
to a hot compressed liquid. As the air conditioning process continues, this is then cooled down
and expanded again to remove heat from the indoor air. More on this later in the article.
Based on the size of your air conditioner, the size of the compressor will vary. You can keep
the most important AC component healthy by often checking for refrigerant leaks, preventing
dirt & contamination, keeping the condenser coils cleaned, and keeping your AC well oiled.

7. Condenser Coil
The opposite of the evaporator, the condenser coil, pulls away heat from the refrigerant and ejects
it to the outside environment. It is located in the outdoor unit of your air conditioner.
The evaporator coil works effectively in reverse to the condenser, with a fan blowing heat away
from it. If you stand outside the outdoor unit of your air conditioner, you will feel hot air blowing
out from it. This is the heat that the condenser is expelling during the process when changing the
refrigerant from hot vapor to a hot liquid.

8. Expansion Valve
In between the condenser and evaporator, there is another little gadget called an expansion
valve. As the refrigerant is now a liquid, it will be unable to absorb the heat. In the expansion
valve, the refrigerant expands into gas after facing a drop in pressure and is also rapidly
cooled. This gaseous, cooled refrigerant then goes into the evaporator coils to repeat the air
conditioning process.

9. Air Conditioning Cycle
All air-conditioning systems utilize a specific material to undergo the phase conversion
process. This material is called a refrigerant, and is contained within tubing which runs
throughout the air-conditioning system. The refrigerant is pulled into the system’s compressor
(item 1 in the diagram below) in the form of a warm vapor after leaving the evaporator coil
(which will be explained further below).
The compressor increases the density of the incoming refrigerant vapor, causing it to increase
in pressure and temperature. This is normally accomplished using a centrifugal system, where a
series of spinning blades rapidly forces the vapor to the outside of the compressor chamber, at
which point it exits. This hot, high-pressure vapor then travels to the air conditioner’s
condenser (item 2) where it moves through a series of coils with thin metal fins attached. A fan
blows air over the fins, and heat moves from the refrigerant to the fins and into the air stream,
very similar to the method a radiator uses to remove heat from the coolant circulating within in
a car engine. The air that is run over the condenser coils is vented to the building exterior and is
released to the atmosphere.

11. This trip through the condenser causes the vapor to lose a significant amount of heat and it
subsequently changes phase from a gas to a high temperature liquid. The liquid refrigerant is
then forced through an expansion valve (item 3) which is basically a pinhole that causes the
liquid to form a mist. A sudden pressure drop and material expansion when the liquid turns
into a mist results in a rapid cooling of the fluid as it throws off heat energy. This cold mist
travels through the evaporator coil (item 4) which is located directly in the air stream of a
circulation fan which pulls air from
within the building. The fan pushes the air across the cold coils, which pulls heat from the air,
causing the air to cool. The transfer of heat to the refrigerant causes it to change back into a
warm vapor and it enters the compressor to begin the cycle again.

12. THANK YOU !