Air Conditioning

1. TYPES OF AlR CONDITIONING SYSTEM
There are three types of Air Conditioners
Room Air Conditioning system
Split air conditioning system
Window air conditioning system
Package Air Conditioning system
Water cooled condenser
Air cooled condenser
Central Air Conditioning system
Direct expansion or DX central Air Conditioning plant
Chilled water central AirConditioning plant. Condens er Fan
Condenser Cos
ROOM AIR cONDITIONING SYSTEM
WINDOW AIR CONDITIONING SYSTEM
Window Air Conditioners are one of the most commonly used
and cheapest type of Air Conditioners.
To install one of these units, you need thgspace to make a slot in
the wall, and there should be some open space behind the
wall
Window air conditioner units are reliable and simple to install
solution to keep a room cool while avoiding the costly
construction of a central air system
Better yet, when the summer heat dies down, these units can be
easily removed for storage and you can use the window sll for
other purpose.
A Oet

2. SPLIT AIR CONDITIONING SYSTEM
SplitAirConditioning system
This is consisted with two parts,
Indoor unit
Outdoor unit
The outdoor unit, fitted outside the room has the components like
compresso, condenser and expansion valve.
The indoor unit comprises the evaporator or cooling coil and the
cooling fan. For this type, we don't have to make any kind of slot in
the wall of the room.
Types of Split Air Conditioning System
Ceiling mounted (Cassette AC)
Floor mounted
NDOC OUTDOO
Duct type.
SPLIT UNIT WINDOW UNIT
Suitable for any room with or Suitable for smali room with a
without a window window sill
Noise is minimal Noise is relatively on the higher
side
Capacity range is0.8 to 2ton Capacity range is 0.75 to 2ton
Need some effort to install Ease to install.

3. AIR COOLED AIR CONDITIONER
PACKAGED AIR CONDITIONERS
The window and split air conditioners are usually used for
the small air conditioning capacities up to 5 tons. The
central air conditioning systems are used for where the
cooling loads extend beyond 20 tons.
The packaged air conditioners are used for the cooling
capacities in between these two extremes. The packaged
air conditioners are available in the fixed rated capacities
of 3,5, 7, 10 and 15 tons.
These units are used commonly in places like restaurants,
I n this packaged air conditioners the condenser ofthe refrigeration system is cooled by
the atmospheric air.
There is an outdoor unit that comprises of the important components like the
compressor, condenser and in some cases the expansion valve
The outdoor unit can be kept on the terrace or any other open place where the free flow
of the atmospheric air is avallable.
The fan located inside this unit sucks the outside air and blows it over the condenser coll
cooling it in the process.
The condenser coil is made up of several turns of the copper tubing and it is finned
externally. The packaged ACS with the air cooled condensers are
used more commonly
than the ones with
water cooled condensers since air is freely available it is difficult
maintain continuous flow of the water.
telephone exchanges, homes, small halls, etc.
As the name implies, in the packaged air conditioners all
the important components of the air conditioners are
enclosed in a single casing like window AC. Thus the
compressor, cooling coil, air
handling unit
and the air filter
are all housed in a single casing and assembled at the
factory location.
The cooling unit comprising of the expansion valve,evaporator,the air handling blower
and the filter are located on the floor or hanged to the ceiling. The ducts comingfrom
the cooling unit are connected to the various rooms that are to be cooled.
Depending on the type of the
coolingsystemusedin
these systems, the packaged air conditioners are divided
into two types: ones with water cooled condenser and the
ones with air cooled condensers. Both these systems have
been described below:
Packaged Air Conditioners with Air cooled Condenser
Packaged Air Conditioners with Watercooled Condenser
Pullela Hemila has left the meeting meet.googe.com 5 Sharing your screen, Stop sharing H0e

4. WATER CoOLED AIR CONDITIONER
Tube within a tube
Water cooled air conditloner Is also called water cooled
condenser as its function is to reject the heat that was
absorbed by the refrigerant in the
evaporator.
Water is used to cool the hot air refrigerant(180'F or 82"C)
The inner tube is inserted into the bigger outer tube and both pipes are formed into
the shape of a col to save space. This is the most commonly used design as it is easyto
manufacture.
Water will fiow through the inner tube and cools the refrigerant that is flowing in the
outer tube. The refrigerant is also cooled by the air in the room.
The inner tube can be designed to have grooved inner tube to increase the heat
transfer between the refrigerant and the water.
Take note that the water and the refrigerant are designed to flow in oppositedirections.
This is known as counter-flow arrangement and its
purpose is tokeep the
difference in
temperature between them consistent throughout the length of the heat
exchange
As the condenser is shaped into a coil, cleaning the inner tube from mineral deposits of
the water mechanically using brush is not possible. The only way to get rid of the
deposits is to use suitable chemical to breakdown the minerals and flushed them aut
from the compressor by pumping counter-flow water in
the condenser.
The water used can be a wastewater system in which the
water is thrown away into the drain after being used
Wastewater system Is not encouraged as it is wasteful and
many states prohibit Its use.
A better option but higher cost is to reclrculate the water
by using a cooling tower. The cooling tower will reject the
heat from the water by forced draft or natural draft.
from the tube.
WATER COOLED AIR CONDITIONER TYPESs
Shell and Coil
Water cooled air conditioner is superior to air cooled air
conditioner as it can operate at lower condensing
temperatures. Water has higher specific heat compared to
air hence its efficiency is higher than air. It is usually used
for capacity in excess of 20 tons.
You do not see a lot of this system in residential houses as
it has a higher equipment cost, requires more
maintenance and higher installation cost. For this reason,
the air-cooled air conditioner is more widely used in
residential houses, cost-sensitive shops and small
factories.
This configuration ofcondenser consists of a shell(can be steel) which contains a coil of
tube which is usually made from copper inside it.
The water will flow thraugh the coil to cool the hot gas refrigerant in the shel. Hot air is
usually feed from the top of the shell and condenses as it flows daown and contact the
coil.
The gas that condenses is further cool down into sub cooling state at the bottom of the
shell.
The minerals that is deposited on the coil from the water cannot be cleaned
marhanirallu ae it ie Inratad inside the shell.
There are 3 main tYpes of water cooled air conditione etgoogiecom s sharimg your screenStopsharing Hioe se chemicals to flush out the minerals.
condensers.
Meeting details Raise

5. Shell and Tube Water Cooled Air Conditioner and Cooling Towers
.Instead ofchannelingthe hot water away to ponds or drainage system after it
is used
to take the heat from the refrigerant, the water can be cooled and then recirculated by
using a cooling tower.
Cooling tower is used to reject the heat from the water to the air. As the tower is
exposed to water and air, it must be corrasive resistant hence the materials used to
build it can be copper, plastic or stainless steel.
The hot water is piped away from the condenser and feed into the cooling tower which
is located away from noise-sensitive premises.
The cooled water that comes out from the cooling tower is then piped back to the
condenser and the whole process repeats.
This type of condenser has a steel shell with
manycopper
tubes inside it. As the cost to produce it is relatively high,
it is only used in higher capacity air conditioning systems.
Water is circulated in the tubes to coolthe refrigerant that
flows into the shell from the top. The shell also acts as a
receiver.
The subcooled liquid refrigerant is channeled out from the
condenser for use in the next stage of the cooling process.
The tubes can be removed from the shell and cleaned out
of mineral deposits in them.
Here are two common types of
Heat rejection method in the
cooling tower
Natural draft uses the
natural air to cool the
water
Forced fan uses a fan to
SEN
move the air over wetted
surface of the warm water.
rConditioning-Systems.com

6. CENTRAL AIR CONDITIONING PLANTS
The name central station system or equipment is also commonly called as applied system or applied machinery. Central station equipment is
associated with installations where the cooling plant is located in the basement or in a penthouse on the roof of multistorey buildings.
It serves air handling equipment and air distribution systems throughout the building. Although size is not
necessarily thecrossover point between
unitary and central station, it is usually acknowledged that central station equipment starts at 25 to 50 tonnes and extends upward to the multi-
thousand- tonne systems.
Another distinguishing difference is that central station systems use the medium of liquid--mostly water- to transfer heating and cooling to a space
air terminal, while unitary systems are based on distributing conditioned air directly to the conditioned space. Unitary equipment makes use of factory
packaged, balanced and tested equipment which requires a minimum of onsite labour and. material to be operational.
Central station systems are made up of
separate components such as chillers, air-handlers, water towers, controls, etc. which can become quite
complex in terms of on-site installations and labour and related trades and crafts. Central station equipment is closely associated with the plan put on
by engineering firms. Equipment is then selected and/or built in order to compliance with these specifications.
cONVENTIONAL CENTRAL STATION SYSTEM:
Cooling tower
1.11.1.1.1 Cold weather
Dypass
The major components are:
1. Water chiller
2. Boiler
3. Air handling unit
4. Water cooling tower
5. Control system
The image shows the schematic diagram ofa unitary split-system for
cooling and is self-explanatory. The same unit can be used as a heat Outdoorair
pump by providing a reversing valve.
Upto 7.5 tonnes, there is no distinct rule to classify a piece of
equipment as commercial or residential, for there is a wide degree of
application in both markets, using the same products. However,
above 7.5 tonnes, the application becomes distinctly commercial,
and the product designs are different in component standards.
Commercial split systems range from 7.5 tonnes to 100 tonnes and
above.
Prehoating
col
Mixed air ir
distribution
Retum airr
handler
Meeting details Rais

7. MMs. B. Amrutha is presenting Sai Kr
and 8
The water chiller will produce 4'C-7C cold water, and by means of a pump, circulate it to the cold water coil in the air handler. Water offthe coil will
generally return at a 6°C rise.
Similarly, in winter, the boiler will produce hot water at 80°C to 90"'C and pump it to the hot water coil. Note that it is possible to have the boiler and chiller
operating at the same time, because in large buildings, there may be need for cooling and heating in different zones.
Condenser water off the chiller (36-37"C) is pumped to cooling tower spray nozzles where it is cooled within the tower to around 30"C and then is
returned to the condenser.
The air handling unit or units, depending on the number of floors or zones, generally contain:
(a) Chilled water coils
(b) Main hot water coils (can be steam)
(c) Humidifier
(d) Filters
(e) Dampers for mixing return air and outside air
(f) Blower and motor.
Apre-heatcol is
frequently required where large amounts
ofoutsideair at or below oC are needed.
Thefaceandby-passdampers either permit all the alr togo through the humidifiers and the heating and coling colils or allow some of it to be by-passed,
depending on the particular situation. All alr to be conditioned is always filtered and cleaned.
AIR HANDLING UNIT (AHU)
An
Air Handling Unit(mostofthetimes abbreviated to AHU), or Air Handler, is a central air conditioner station that handles the air that, usually, will be
suppliedinto the buldings bythe ventilation ductwork (connected totheAHU). Handling the air means that the alr will be delivered into the building
spaces with thermo-hygrometric andIAQ (lndoor Air Quality) treatment. The accuracyof the treatment will depend from the specificity of each project
(offices, schools, swimming-pools, laboratories,factories with industrial processes, etc). This means, the Air Handling Unit treat the air by filtering, cooling
and/or heating, humidifying and/or dehumidifying.
There areseveraltypes ofAir
HandlingUnits: Compact, Modular, Residential, DX integrated, Low Profile (ceiling), Packaged, Rooftop mounted (typically on
the roofs of buildings, with special weather protection), etc.
Meeting details Raise

8. and 9
CONSTRUCTION
Usually the Air Handling Units have a casing (also known box) constructed by a framing system and double skin insulated panels (also known as insulated
sandwich panel).
The most common framing materials are galvanized steel, AluZinc or aluminium. Regarding the panels skin, the most common materials are galvanized steel
and AluZinc.
In hygienic AHU's the inner skin usually is made from stainless steal or AluZinc with a special painting finishing
The materials used to insulate the panels are 99% of the times mineral wool (also known as stone wool or mineral fiber) or PU (Polyurethane). Some
manufacturers choose the mineral wool and some the PU, it all depends the compromise between thermal characteristics, acoustic attenuatlon, mechanical
strength and production costs that each one is looking for the final product.
All the components will be installed inside the casing. The casing is installed on
top of a base (or chassis)
COMPONENTS
To be considered as an Air Handling Unit a minimum of components must considered, to know: at least 1 filtration section, 1 heat transfer component
(cooling/heating coil or heat recovery system) and 1 fan.
The Air Handling Units can have several components, depending on the complexity and
requirements, such as
energy efficiency, of each specific buildingand
application.
Some of the most known components are:
Fans (Plug Fans, Double Inlet, Single Inlet, Axial, etc)
Filters (Plate Filters, Bag Filters, Compact Filters, EPA Filters, HEPA Filters,
ULPA Filters, Carbon Fllters)
Cooling/Heating Coils (water/steam/Direct Expansion DX/electric/gas fired)
Heat recovery systems (cross flow plate heat exchangers, cross flow plate
heat exchangers, heat wheel/rotating heat exchangers, run
around coils and heat pipes, etc)
Humidifiers (Adiabatic/Evaporative Pad, non-pressurized
Steam, pressurized steam)
Dehumidifiers (DX coil, desiccant rotor)
-
Ultraviolet UV disinfection lamps
Photocatalytic oxidation (PCO) air cleaners
Sound attenuators
meet.google.coms sharing your screen.
Stop sharing
Mist/Droplet eliminators
Dampers

9. Due tovarious sources of heat the temperature inside the room becomes very high and the relative humidity can also be high
Further they can also be less flow of air inside the room
All these factors lead to creation of highly uncomfortable conditions inside the room.
The heat produced in two ways:
Human beings
Electrical and electronic appliances.
The control of these conditions may be desirable to maintain the health and comfort of occupants, or to meet the requirements of industrial processes
irrespective of the external climatic conditions.
Air conditioning is the process of altering the properties of air (primarily temperature and humidity) to more favorable conditions.
Air conditioning is a process of removing heat froma confined
space, thus cooling the air, and removing humidity.
Air conditioning can be used in both domestic and commercial
Retrineea
a
and mox
her
nto the a ped
environments.
This process is used to achieve a more comfortable interior
environment, typically for humans or animals, however air
conditioning is also used to cool/ dehumidify rooms filled with
heat producing electronic devices , such as computer servers,
power amplifiers and even to display and store artwork.
house
arm a
ped
Cogled re dee
e
Our
primary goal is todscharge
warm air from inside to the exterior
meetgooge.com 5 sharing your scteen.

10. Water Chiling Equipment may be:
1. Packaged chillers - Lower capacity.
2. Centrifugal chillers (Hermetic)- Very large capacities upto 1300 tonnes.
3. Screw compressor chillers.
4. Absorption chillers.
Cooling coils in central air conditioning station may use either chilled water circulating through the coils or there may be chilled water
evaporators (chilled water sprays) or air-washers. In this case, chilled water works as a secondary refrigerant.
Direct Expansion and Chilled water
The central air conditioning plants or the systems are used when large buildings, hotels, theaters, airports, shopping malls etc are to be
air conditioned completely.
The window and split air conditioners are used for single rooms or small office spaces.
If the whole building is to be cooled it is not economically viable to put window or split air conditioner In each and every room.
Further, these smal units cannot satisfactorily cool the large halls, auditorilums, receptions areas etc.
In the central air conditioning systems there is a plant room where large compressor, condenser, thermostatic expansion valve and the
evaporator are kept in the large plant room.
They performallthe functions as usual similar to a typical refrigeration system. However, all these parts are larger in size and have
higher capacities.
The compressor Is of open reciprocating type with multiple cylinders and is cooled by the water just like the automobile engine.
The compressor and the condenser are of shell and tube type. While in the small air conditioning system capillary is used as the
expansion valve, in the central air conditioning systems thermostatic expansion valve is used.
The chilled is passedvia theductsto allthe rooms,
hallsand other spaces that are to be air
conditioned. Thus in all the rooms there is
onlythe duct
passingthe chlledair and
thereare no
individual cooling colls, and other parts of the refrigeration system in the rooms.
Whatis wegetin eachroomisthe
completely silent and highlyeffective air conditions system in the room. Further, the amount of
chilled air that is needed in the room can be controlled by the openings depending on the total heat load inside the room.
meet.googe.com is sharing your screen,
Stopsharing
Meeting details Raise

11. The central air conditioning systems are highly sophisticated applications of the air conditioning systems and many a times they tend to
be complicated. It is due to this reason that there are very few companies in the world that specialize in these systems. In the modern
era of computerization a number of additional electronic utilities have been added to the central conditioning systems.
There are two types of central air conditioning plants or
systems:
DirectoxpansionorDXcentralairconditioningplant:Inthis
system the huge compresso, andthecondenserare housedintheplant
room,whiletheexpansion valve and the evaporator or
thecooling coil and
the air
handling unit are housed in separate room.
The cooling coil is fixed in the air handling unit, which also has large blower housed in it.
The blower sucks the hot return air from the
room via
ducts and blows it
overthe coolingcol
The cooled air is then supplied through various ducts and into the spaces which are to be cooled. This type of system is useful for small
buildings
Chilled watercentralairconditioningplant:This type of system is more useful for large buildings comprising of a number of floors. It
has the plant room where all the important units like the compressor, condenser, throttling valve and the evaporator are housed. The
evaporator is a shell and tube. On the tube side the Freon fluid passes at extremely low temperature, while on the shell side the brine
solution is passed. After passing through the evaporator, the brine solution gets chilled and is pumped to the various air handling units
installed at different floors of the building. The air handling units comprise the cooling coil through which the chilled brine flows, and the
blower. The blower sucks hot return air from the room via ducts and blows it over the cooling coil. The cool air is then supplied to the
space to be cooled through the ducts. The brine solu
and is again pumped back to the air handling unit.
To operate and maintain central air conditioning systems you need to have good operators, technicians and engineers. Proper
preventative and breakdown maintenance of these plants is vital
which has absorbed the room heat comes back to the evaporator, gets chilled
top sharing Hide
nolt.sem sharing your sceen.

12. BASIC ELEMENTS OF AIR CONDITIONING SYSTEM EXPANSION VALVE
Compresser
Condenser
The main purpose of this is to remove pressure from the liquid
refrigerant to allow expansion or change of state from a liquid to a
Expansion valve vapor In the evaporator.
evaporator The high pressure refrigerant entering the expansion valve is quite
warm.
cOMPRESSER The two main types used in air conditioning system are:
Internally equalized valve: most common
Externally equalized valve: for special control.
This is used to remove the heat laden vapor refrigerant from the
evaporator of the air conditioning systems.
There are basically 5 types of
Air Conditioning compressors
that are commonly
used in HVAC industry:
Reciprocating
AC
Scroll
Screw ow
Rotary
Centrifugal
cONDENSER EVAPORATOR
This remove heat from air, water or other substance.
Refrigerant liquid is converted to gas, absorbing heat from the air in
the compartment.
High P
In systems involving heat transfer, a condenser
is a device or unit used to condense a
substance from its gaseous state to
liquid state by cooling it.
There are basically three types of condensing
unit depending on how the heat is removed
by the condensing medium which is usually
water, air or a combination of both
**
O***"
Air-cooled
Water-cooled
meet.google.com s sharing your screen
Stopsharing
Evaporative

13. VRF (VARIABLE REFRIGERANT FLOw (VRF) air conditioning system?
Accordingto ASHRAE, The term variablerefrigerantflow refers to the ability of the system to control the
amount ofrefrigerantflowing to each of the evaporators, enabling the use of many evaporators ofdiffering
capacities and configurations, individualized comfort control, simultaneous heating and cooling in different
zones, and heat recoveryfrom one zone to another.
In layman's terms, VRF systems are essentially larger, more complex, versions of direct expansion (DX) split
systems much like the one you likely have in your home.
The technology was pioneered in Japan by Daikin back in the early 1980s, but has only recently gained
popularity in the United States.
These systems have continued to advance over the years, and numerous other notable manufacturers like LG,
Mitsubishi, and Trane also offer versions of VRF systems.
The diagram beside indicates how
a single outdoor VRF condensing
unit can serve various styles of
indoor units (wall mounted,
ceiling cassette, concealed
ducted, PTAC style).
meet onngle.coms sharing your screen. Stop shaning

14. ADVANTAGES OF VRF over traditional systems, such as:
Construction Flexibility- The modular nature of both the indoor and outdoor units simplify installation and
allow for future expansion.
Occupant Comfort-VRF systems rely largely on individual zone control and can hold a more consistent
temperature in a space.
Energy Efficiency - VRF systems are highly efficient. This carries increased importance as building energy codes
are becoming more and more stringent and owners are recognizing the rising cost of energy from utilities.
(These systems are often used in LEED and Austin Green Building Program compliant buildings due to their
energy efficiency.)
System Redundancy-VRF condensing units are often equipped with multiple compressors. This provides a level
of redundancy as compared to standard split systems where each indoor unit is paired with a dedicated
outdoor unit with a single compressor.
Installed Capacity Reduction - A reduced total tonnage of air conditioning equipment is installed to serve a
building due to the ability to shift heating or cooling capacity from one part of a building to another.
Sound levels -VRF indoor and outdoor units create much less noise than traditional DX split systems.
meet. google.com is sharing your screen.
Stopsharing Hide

15. PROCESS OF AIR-CONDITIONING
Remoe
Evaporator
Suction Line
Cool Compressor
Warm
indoor air
1 Indocr
Blower
Capllery hdbe
Condenser
Ambient (Condenser
Hct
condenser
outside air) in
Thermostatic
ExpansionValve Sandeser Fan 3 ir out
meet.google.com is sharing your screen. Stopsharing Hide
http://www.centrakair-conditioner-and-refrigeration.com/

16. LOW SIDE HIGH SIDE
(low pressure) (high pressure)
Expansion
Valve
Heat istransfered
from Inside air
to refrlgerant
Low
Pressure
Uguld
High
Pressur
Liguld
Evaporator Condenso
Low
Preesur
Gas
High
Precsure
Gas Heat is transfered
from rengerant
to outside air
Compressor

17. DISADVANTAGES OF VRF systems:
Dedicated Outside Air - A dedicated outside air system is required. The VRF indoor equipment is small/modular
and not designed to process large amounts of outside air that might be required in densely occupied building.
First Costs-First costs are higher when compared to other system types, but the savings in energy typically
returns the initial investment within 5 years or less.
With an initial investment, utilizing VRF technology on your next project can reduce energy costs, improve
occupant comfort, reduce mechanical unit noise and reduce down time due to increased redundancy within the
system.
9m sharing vour screen, Stop sharing Hide

18. VRF HVAC technology myths & facts
Fact: VRF systems provide simultaneous heating and cooling. A VRF HVAC system can heat and cool different
zones or rooms within a building at the same time. If the appropriate VRF system is selected, building occupants
have the ability to customize the temperature settings to their personal preferences
Myth: VRF can only be used in commercial applications. VRF equipment can be used in conjunction with a
wide range of heating and cooling products. This means that a VRF system can be scaled to meet the climate
control needs of a small single-family residence all the way to a commercial high-rise building.
Fact: VRF systems run at a very low volume. Unlike some older HVAC technologies, VRF systems are extremely
quiet. Installing a VRF system has the added benefit of reducing ambient noise both inside and outside of a
building.
Myth: VRF HVAC units are bulky. VRF equipment is sleek and compact compared to other HVAC equipment.
This makes VRF an excellent solution for installing HVAC equipment in areas with limited space, such as when
renovating historical buildings.
Fact: VRF systerms are easy to install. Because VRF equipment weighs much less than ducted equipment,
installing a VRF system is easier and requires less physical effort than a traditional HVAC system.
meet gcoge com s sharmg your sreer. 5top sharina Ha