Unit 8
Air Conditioning System
Introduction
Air conditioning is the process of giving comfort to the occupant in a
particular space irrespective of any external climatic conditions
Air conditioning systems are broadly classified into
1. Comfort Air conditioning
It is the process of giving comfort atmosphere to majority of the
occupant
It is subdivided into
Summer A/C
Winter A/C
Year – round A/c
2. Industrial Air conditioning
It provides air at required temperature and humidity to perform a
specific industrial process successful
Design conditions are not based on human comfort but purely on
the requirement of industrial process
Split Air Conditioner
Also known as split units
There are basically 2 casings that are
mounted one at the indoor and the
other at the outdoor
Compared to the windows Units, it is
less noisy
Piping connects the two units
Split Air Conditioner
Split Air Conditioner
Split Air Conditioner
Packaged Air Conditioner
Packaged Air Conditioner
Packaged Air Conditioner
Packaged Air Conditioner
Packaged Air Conditioner
Packaged Air Conditioner
Packaged Air Conditioner
Central Air Conditioner
In central air conditioning, air, water, or both are used as working
fluids to
produce the required heating and/or cooling, and therefore based
on working fluids, central air conditioning systems can be
classified into three groups namely:
1.All-air systems: in these systems air is used as working fluid for
heating and/or cooling purposes.
2.All-water (hydronic) systems: in these systems water is used as
working fluid
for heating and/or cooling purposes.
3.Air-water systems: in these systems both air and water are used
as working
fluids for producing heating and cooling purposes
Central Air Conditioner
In all air system, the air is conditioned with the help of an air
conditioning plant which is located at a remote area.
Duct works are used to connect the plant and the space to
be conditioned.
The conditioned air is sent through the ducts and
distributed into the air conditioned space through inlets.
This type can be adopted both for comfort and industrial AC
It can be applied in buildings requiring individual control of
conditioning and also for office buildings, restaurants,
hospitals, stores which require multiple zone conditioning.
When load in the space changes, the required property of
the air should change.
Various methods are used in this system to maintain the air
property within the desired limit when load changes.
Central Air Conditioner
Automotive Air conditioning
•Automotive air conditioners cool the interior of the passengers
compartment by moving heat from inside the car to outside the
car.
•By cooling the air in the passengers compartment, humidity is
also lowered for improved passenger comfort.
•Heat is removed from the interior of the car by evaporating a
liquid inside the passengers compartment.
•The evaporating liquid will absorb the latent heat of vaporization
from the interior of the car
•The resulting gas is then condensed outside the car and the
latent heat of condensation is released to the outside air.
Automotive Air conditioning
There are two main types of air conditioning systems in use in the automobile
industry today. The main difference between each system is the type of device
that is used to lower the refrigerant pressure. You can either use an expansion
valve or orifice tube hence we have two systems:
The expansion valve system
The fixed orifice tube system
Expansion valve system
Automotive Air conditioning
The fixed orifice tube system
The fixed orifice tube system functions in
exactly the same way as the expansion
valve system, apart from one component.
Instead of the expansion valve, this
system has got a fixed orifice tube. The
fixed orifice tube has got the same
function as the expansion valve, to allow
a metered quantity of high-pressure liquid
refrigerant into the evaporator.
Evaporative Cooling and Desert Cooler
Evaporative Cooling : It is a cooling and ventilation technique that uses water
as its refrigerant.
During the evaporative cooling process, water is evaporated in a stream of air
and passes from a liquid to a gas. This transition requires energy, which is
extracted from the air in the form of heat. As a result of this process, the air is
cooled down.
In an evaporative cooling system, hot outside air is forced through wet cooling
pads by means of a motor-driven fan.
The cooling pads are moistened continuously by a water pump that delivers
water to the cooling pads.
The cooled down air is then blown into the building. The outcoming air can
then be cooled down between 60 and 90 % of the wet-bulb depending on the
effectiveness of the evaporative media.
The outcoming air is cooled down 10 to 15 °C but contains a high amount of
humidity. Therefore direct evaporative cooling is not recommended for
cooling in work and living environments.
Evaporative Cooling and Desert Cooler
Desert Cooler:
Desert air coolers have pads present on 3 sides of a cooler which are
constantly drenched with water with the help of a pump present in
the air cooler. When the evaporated air passes through these cooling
pads it mingles with the cold water and becomes colder.
Desert air coolers are suitable for places where humidity is low and
the temperature is high. These coolers also work on the principle of
evaporating heat from water and pushing cool air. As such conditions
are mainly found in desert areas, thus it gets the name 'desert cooler
Why is desert cooler better in summer?
Lesser the humidity and higher the temperature, the faster is the
evaporation. So on a hot dry day, the humidity is less. Thus water
present inside the desert cooler evaporates more, thereby cooling the
surroundings more. That is why a desert cooler cools better on a hot
dry day.
Thank you
