AIR FLOW SYSTEM FOR RESIDENTIAL AND COMERCIAL BUILDINGS.

1. ∗AIR CONDITIONING SYSTEM
Submitted By:
GAURAV SHEKHAR
JYOTI CHAUHAN
REPORT
BUILDING SERVICES
Submitted to:
AR. VISHAL JAIN

2. ∗ AN IDEAL AIR CONDITIONING SYSTEM SHOULD MAINTAIN CORRECT
TEMPERATURE, HUMIDITY, AIR PURITY AND AIR MOVEMENT IN A
SPACE.
CLASSIFICATION OF AIR CONDITIONING SYSTEM
1. CENTRAL STATION AIR CONDITIONING SYSTEM
2. UNITARY A/C SYSTEM
3. DIRECT A/C SYSTEM
WHAT IS AIR CONDITIONING?

3. Refrigeration Cycle Simplified
Evaporator
Step One
Compressor
Step Two
Condenser
Step Three
Expansion
Valve
Step Four

4. CENTRALISED AIR CONTIONDITIONING SYSTEM
∗ This system is applied for conditioning areas more then 500 sq. m.
∗ CENTRAL A/C SYSTEM OFFERS THE ADVANTAGE OF
consolidated maintenance
much lower operating costs.
∗ USED IN
Cinema halls
Auditoriums
One or two storey office buildings
Libraries
Shopping malls
Hotels
Hospitals

5. Split-System Units
Partially inside and
partially outside
(separate hot side
from cold side)
Hot side=condensing
unit=outside
Cold side=coils and
expansion valve-air
ducts to carry air

6. 1. COOLING AND DIHUMIDIFYING COILS
2. HEATING COILS
3. BLOWER WITH MOTORS
4. SPRAYS FOR COOLING, DEHUMIDIFYING OR WASHING
5. AIR-CLEANING EQUIPMENTS
6. A CONTROL DEVICE
The central a/c system serves different rooms through extensive duct
work with individual control. The system may use one of the
following method to supply the conditioned air:
Air is conditioned in central conditioned room and is supplied to the required
rooms with controlled air discharge in each room.
1. The water is chilled in the central conditioned room and is supplied to the
required rooms with individual flow control.
2. Individual evaporator in each room with thermostatic flow control or direct
expansion system.
COMPONENTS REQUIRED FOR ASSEMBLING A CENTRALISED AIR
CONDITIONING SYSTEM

7. WINDOW AIRCONDITIONING UNITS
∗ Easiest mode of air conditioning for any space
∗ Units required for the unit area power connection(220 Volts, single phase,
AC power) through a 15 amps power socket, and condensate drain
disposal.
∗ In hot and dry climates like delhi, U.P. , Rajasthan and others, efficiency of
unit is improved by placing a water tray on top of the unit which
evaporatively cools the air used for condensing and refrigerant.
∗ Window units are recommended for aironditioning of a maximum of upto
100 sq. m floor space, which has a limited depth upto 10 m, and has
external periphery to allow mountings of these units.
∗ The major advantage of window units is the ease of installation and
relatively low capital cost.
WINDOW UNITS ARE COMMERCIALLY AVAILABLE in nominal capacities of 1
TR, 1.5 TR and 2 TR; the actual capacity being somewhat smaller.
Here TR is TON OF REFRIGERATION.

8. MAJOR DISADVANTAGES
∗ Poor air distribution (supply/ return from same face)
∗ Can be best serve for the space upto 5m deep
∗ Requires external window for mounting
∗ Generates excessive noise in conditioned area
∗ Unit is prone to compressor burn out due to voltage fluctuations
MAJOR ADVANTAGES
∗ INSTALLATION AND ASSEMBLY LABOUR CHARGES ARE LESSER
∗ ZONNING OR ASSEMBLY DUCT WORK IS ELIMINATED
∗ FAILURE OF THIS UNIT PUTS OFF CONDITIONING IN ONLY ONE ROOM
WHEREAS THE FAILURE OF CENTRAL PLANT OFF-SETS ALL THE ROOMS
TO BE SERVED
∗ IT CAN MEET THE REQUIREMENTS OF EACH ROOM SEPERATELY
∗ INDIVIDUAL ROOM CONTROL IS THE SPECIFIC FEATURE OF THIS
SYSTEM

9. COMMERCIAL AVAILABILITY – Central DX systems have nominal refrigeration
capacities of 20, 30, 40, 60, 120 and 150 TR.
∗ It generally houses refrigeration machinery as well as air handling units, and
should be preferably located on the lowest floor.
∗ Can serve a maximum of two floors with preferably air handling units serving so
as to prevent spread of fire and possible smoke.
THUMB RULE FOR SIZING PLANT ROOM
50 TR= 50 sq. m area X 3.2 m high
100 TR= 70 sq. m area X 3.6 m high
∗ Natural ventilation and natural light are desirable but often one has to design
only with mechanical ventilation and artificial lighting, with emergency lights
and fire exit doors.
∗ Each handling unit can serve upto 500 sq. m. conditioned area and requires a
room size of 4.5 m X 4.5 m X 3m high
∗ Services required in AHU room are fresh air, condensate drain disposal and
power supply.

10. ∗ AHU room doors must be open outward
∗ Generally two walls and ceiling of AHU rooms are acoustically
∗ Conventionally these systems are designed for designed for water
cooled condensing, achieved by cooling towers mounted on roof top, or
frequently, by spray ponds outside the building.
∗ Whereas, the spray pond are aesthetically most desirable, these are
expansive(3 to 4 times more than the cooling towers) , require frequent
cleaning and change of water and constant removal of falling leaves and
algae, repairs and maintenance of strainers and nozzles.

11. 1. CAPITAL COST AND RUNNING COST ARE LESS PER UNIT REFRIGERATION.
2. IT CAN BE LOCATED AWAY FROM THE AIR-CONDITIONED PLACES WHICH IS
USEFUL AND LESS COSTLY.
3. NOISE AND VIBRATION LEVEL ARE LESS TO THE PEOPLE LIVING IN AIR-
CONDITIONED PLACES AS THE AIR-CONDITIONED PLANT ARE FAR AWAY
FROM THE AIR-CONDITIONED PLACES.
4. BETTER ACCESSIBILITY FOR MAINTENANCE.
DISADVANTAGESOF CENTRALISED AIR CONDITIONING SYSTEM
1. INSTALLATION AND ASSEMBLY LABOUR CHARGE IS HIGH.
2. ZONNING OR EXTENSIVE DUCT WORK IS TO BE DONE.
3. PLANTS MUST BE KEPT RUNNING EVEN ONLY FEW ROOM IS TO BE AIR-
CONDITIONED.
4. FAILURE OF A/C PLANT OFF-SETS ALL THE ROOMS TO BE SERVED.
5. CENTRAL SYSTEM CANNOT MEET THE INDIVIDUAL NEEDS OF EACH ROOM.
6. INDIVIDUAL ROOM TEMPERATURE CANNOT BE CONTROLLED BY THIS
SYSTEM.
ADVANTAGES OF CENTRALISED AIR CONDITIONING SYSTEM