The document discusses air conditioning and window air conditioners. It defines air conditioning as altering air properties to improve comfort and indoor air quality. It then describes the main components and working of window air conditioners, including the refrigeration system, air circulation system, and control system. The key advantages are that window units are economical and easy to install, but limitations include lack of humidity control and inability to heat in winter.

1. WHAT IS MEANT BY AIR CONDITIONING
• Air conditioning is the process of
altering the properties of air to more
comfortable conditions, typically with
the aim of distributing the conditioned
air to an occupied space to
improve thermal comfort and indoor air
quality.
• In common use, an air conditioner is
a device that lowers the air
temperature.
• In the most general sense, air
conditioning can refer to any form of
technology that modifies the condition
of air (heating, cooling,
(de)humidification, cleaning,
ventilation, or air movement).

2. HUMAN COMFORT
• Human comfort is achieved when the environment provides the
appropriate conditions to avoid feeling too cold or hot, according to
Weather Prediction. Six factors influence human comfort:
temperature, clothing, wind speed, sunlight, humidity and evaporative
cooling
• Most people are comfortable when the air temperature is between 18-
25deg.C

3. WHY DO WE NEED AC
• In a well climatically designed building human comfort factors are
controlled naturally, that is the best solution.
• In big building/complexes it is not possible to design entire building
comfortably by natural energy sources like sun, wind, orientation etc.
In such cases we have to take the help of mechanical mean for
obtaining comfortable conditions inside the building.
• Outside air is quite likely to be at a different condition from the
required comfort zone condition. In order to bring its condition to
within the comfort zone we may need to do one or more of the
following:-heat it; cool it; dehumidify it; humidify it; or mix it.

4. WINDOW AC
• Window air conditioners are one of the most
commonly used and cheapest type of air conditioners
• To install one of these units, you need the space to
make a slot in the wall, and there should also be some
open space behind the wall.
• Easy to install, mobility and shifting.
• Costs lesser in comparison to other varieties
• Single unit with compressor and condenser.

5. PARTS OF THE WINDOW AIR CONDITIONERS
• The whole assembly of the window air conditioner can be divided into
two compartments:-
The room side, which is also the cooling side and the outdoor side
from where the heat absorbed by the room air is liberated to the atmosphere.
In the front of the window air conditioner on the room side there is
beautifully decorated front panel on which the supply and return air
grills are fitted (the whole front panel itself is commonly called as
front grill).
The louvers fitted in the supply air grills are adjustable so as to supply
the air in desired direction.
There is also one opening in the grill that allows access to the control
panel or operating panel in front of the window air conditioner.

7. The various parts of the
window air conditioner
can be divided into
following categories:
• the refrigeration
system,
• air circulation
system,
• ventilation system,
• control system,
• electrical protection
system.

8. The REFRIGERATION SYSTEM of the window air conditioner comprises of all
the important parts of the refrigeration cycle. These include
the compressor,
condenser,
expansion valve and
the evaporator.
The refrigerant used in most of the window air conditioners is R22.
The compressor used in the window air conditioners is hermetically sealed
type, which is portable one. This compressor has long life and it carries long
warranty periods. The condenser is made up of copper tubing and it is cooled
by the atmospheric air. The condenser is covered with the fins to enable faster
heat transfer rate from it.
The capillary tubing made up of various rounds of the copper coil is used as the
expansion valve in the window air conditioners. Just before the capillary there is
drier filter that filters the refrigerant and also removes the moisture particles, if
present in the refrigerant.
REFRIGERATION SYSTEM

9. Like condenser, the evaporator is also made up of copper tubing of number of turns
and is covered with the fins.
the evaporator is also called as the cooling coil since the rooms air passes over it and
gets cooled. Just in front of the evaporator there is air filter fitted in the front panel or
front grill.
As the room air is absorbed, it is first passed over the filter so that it gets filtered. The
filtered air is then blown over the cooling coil and the chilled air is passed into the room.
The refrigerant after leaving the cooling coil enters the accumulator where it is
accumulated and then it is again sucked by the compressor for recirculation over the
whole cycle.

12. The air circulation system of the window air
conditioner comprises of the following parts.
1) Blower : This is the small blower that is
fitted behind the evaporator or cooling coil
inside the assembly of the window air
conditioner system. The blower sucks the air
from the room which first passes over the air
filter and gets filtered. The air then passes over
the cooling coil and gets chilled. The blower
then blows this filtered and chilled air, which
passes through the supply air compartment
inside the window air conditioner assembly.
This air is then delivered into the room from the
supply air grill of the front panel.
AIR CIRCULATION SYSTEM

13. 2) Propeller fan or the
condenser fan : The
condenser fan is the forced
draft type of propeller fan that
sucks the atmospheric air
and blows it over the
condenser. The hot
refrigerant inside the
condenser gives up the heat
to the atmospheric air and its
temperature reduces.

14. 3) Fan motor : The motor inside
the window air conditioner
assembly is located between the
condenser and the evaporator coil.
It has double shaft on one side of
which the blower is fitted and on
the other side the condenser fan is
fitted. This makes the whole
assembly of the blower, the
condenser fan and the motor
highly compact.

15.  The air moving inside the room and in the front part of the air
conditioner where the cooling coil is located is considered to be the
room air. When the window AC is started the blower starts
immediately and after a few seconds the compressor also starts.
The evaporator coil or the cooling gets cooled as soon as the
compressor is started.
 The blower behind the cooling coil starts sucking the room air, which
is at high temperature and also carries the dirt and dust particles. On
its path towards the blower, the room air first passes through the
filter where the dirt and dust particles from it get removed.
WORKING OF WINDOWS AC

16. The air then passes over the cooling coil where two processes
occur. Firstly, Due to this the temperature of the room air
becomes very low, that is the air becomes chilled. Secondly,
due to reduction in the temperature of the air, relative humidity
reduces.
This air at low temperature and low humidity is sucked by the
blower and it blows it at high pressure. The chilled air then
passes through small duct inside the air conditioner and it is
then thrown outside the air conditioner through the opening in
the front panel or the grill. This chilled air then enters the room
and chills the room maintaining low temperature and low
humidity inside the room.

17.  The cool air inside the room
absorbs the heat and also the
moisture and so its temperature
and moisture content becomes
high. This air is again sucked by
the blower and the cycle repeats.
Some outside air also gets mixed
with this room air. Since this air is
sent back to the blower, it is also
called as the return room air. In
this way the cycle of this return air
or the room air keeps on
repeating.

18. ADVANTAGES
 Window ac don’t need such complex installation.
 We can install these units all by ourself.
 More economical and efficient.
 Can be fitted in any kind of windows with small
adjustments.
 They are portable.

19. LIMITATIONS OF WINDOW AC
 No humidity control though it carrier out dehumidification.
 Most of the window ac conditioners do not provide heating for
winters.
 No provision for humidification in window ac conditioner.
 Outside temperature above 40 degree c can cause derating of
the conditioner.
 Cover big part of window and cut down sunlight and natural
ventilation.

20. PRECAUTIONS TO BE TAKEN WHILE INSTALLING
WINDOW AC
1) It should be fitted with a small slope (3 deg. To 5
deg.) downward, towards the outside which ensures
that draining of condensate at the cooling coil it
outside the room.
2) It should be ensured that the condenser is not
exposed to direct solar heat to prevent a new rise in
condenser pressure.
3) The gaps between the wall opening and the
package should be blocked by insulation