Air Conditioning System (Part 2) By : Rafikullah Deraman, Lecturer JKA, Polisas
Jan 11, 2016
Air Conditioning System (Part 2)
By : Rafikullah Deraman,
Lecturer JKA, Polisas
Learning Outcome: At the end of this lesson, student should be able to:
• Differentiate types of air conditioning system
• Calculate the size of air-conditioner systems
• Window unit, are sufficient when cooling a single room or
small space.
• If you do choose a window unit, it is extremely important
that they are sized for the area being cooled.
• Capacity for cooling load is between 6000- 32,000 BTUH
• Under sizing a unit will cause the unit to run constantly
which will drive up your electric bills.
• On the other hand, if the unit is too large it won’t run long
enough to remove humidity.
• High humidity can cause poor indoor air quality.
RA-10KF-Hitachi
1.0hp Window Type Air Conditioner,
Cooling capacity: 9,010 BTU/h
Product in the Market
Advantages
• They are relatively inexpensive
• Easy to install Disadvantages:
• Higher noise levels
• Physical appearance( typically unattractive)
• Lower efficiency
• Limited cool up to two rooms
• Poor constant temperatures
Win
do
w U
nit
Split Unit
4 indoor air-handling units c/w Single unit outdoor
Split U
nit
A split-system air conditioner splits the hot side from the cold side of the system, as in the diagram below. Outdoor unit: The outdoor unit contains a compressor and a condensing coil filled with refrigerant. Indoor unit: The indoor unit is made up of a coil and blower which is located inside
RAS-S10CC - Hitachi 1.0hp Wide Deluxe Air Conditioner, Cooling capacity: 10,110 BTU/h RAS-S13CY - Hitachi 1.5hp Deluxe Air Conditioner, Cooling capacity: 12,020-12,090 BTU/h
RAS-S18CAM 2.0hp Deluxe Wide Air Conditioner‚ Cooling capacity: 17,410 -17‚750 BTU/h
RAS-24CE9G 2.5hp Deluxe Wide Air Conditioner, Cooling capacity: 24,060 BTU/h
Advantages: • Flexibility and size. Since they are small units, they can easily be installed. More so, their flexibility is perfect for warming and cooling of rooms. Most of the models of split types encompass 4 indoor air-handling units, which are connected to a single unit placed outdoors. These 4 indoor air-handling units are able to cool down and heat up 4 rooms or zones.
Advantages: Easier to install • most of split types can be quickly and easily
installed. • a window or wall opening is not required to
install split ac units. • The indoor unit can be placed on the floor,
hung on wall brackets or mounted on the ceiling. The outdoor unit is obviously installed outside of the buildings.
Advantages: Easy maintenance • The split ac units system should be
maintained on a regular basis (at least twice a year).This will ensure that it always runs at its optimum performance levels, in terms of both power and efficiency.
• Easily maintained on the basis that they will normally have a filter which is washable.
• A regular maintenance will also ensure the longevity of the split ac units system.
Advantages: Quiet operation • The split ac units system is very quiet in
comparison to other air conditioning systems.
• The minimization of noise is importance in rooms which require a peaceful environment
Advantages: Cost effective • With regards to the initial cost of purchasing split
ac units it may be prudent to note that four indoor units can operate from one outdoor unit.
• The running costs of the split ac units are also cost effective. Split ac units are extremely energy efficient.
• Energy efficiency ensures that the split ac units do not work any harder than is ultimately required, thereby minimizing electrical energy consumption on an on going basis.
Advantages: Simple control
The Split ac units are simple to operate and are
therefore suitable for every and any individual
considering the purchase of an air conditioning
system.
Disadvantages: 1. Sometimes the indoor and outdoor unit fan becomes
noisy.
2. Each unit or group of units has a filter, compressor and
refrigeration pipework that needs periodic maintenance
and possible re-charging.
3. Units have course filters therefore filtration is not as
good as with AHU’s.
4. The installation may require long runs of refrigerant
pipework which, if it leaks into the building, can be
difficult to remedy.
Disadvantages: 5. Not at robust as central plant.
6. The majority of room air conditioners just recirculate air in
a room with no fresh air supply although most
manufacturers make units with fresh air capability.
7. Cooling output is limited to about 9 kW maximum per unit;
therefore many units would be required to cool rooms with
high heat gains.
Package Unit
The package unit refer to the components namely
The compressor
The cooling coil
The condenser
The evaporator
are all packaged, designed and matched up by the
manufacturer to form a complete system.
Usually used for medium and large installation air
conditioning system.
Cooling load capacity between 24,000 to 360,000 BTUH
Used with and without a ducting system.
Model Nominal
Tons
Height
(in.)
Width
(in.)
Length
(in.)
Capacity
Cooling-
BTUH
SEER
TCY024G 2 29 36 56 24,000 14.00
TCY030G 2.5 29 36 56 30,600 14.00
TCY036G 3 29 36 64 36,000 14.10
TCY042G 3.5 29 36 64 41,500 14.00
TCY048G 4 33 45 65 49,000 14.40
XL1400 SINGLE PACKAGE AIR CONDITIONER
Model Nominal
Tons
Height
(in.)
Width
(in.)
Length
(in.)
Capacity
Cooling-
BTUH
SEER
TCY024F 2 29 36 56 24,000 12
TCY030F 2 1/2 29 36 56 30,000 12.3
TCY036F 3 29 36 64 36,000 12
TCY042F 3 1/2 29 36 64 41,500 12
TCY048F 4 33 45 65 48,000 13.05
TCY060F 5 33 45 65 60,000 12.4
XL1200 SINGLE PACKAGE AIR CONDITIONER
Advantages :
1. A packaged unit saves precious space. Especially
in an office that probably has limited space.
2. Low installation cost
3. Simple operation- trained man power is not
required.
4. Possible to switch off unit catering to unoccupied
spaces thereby avoiding wastage
5. Less plant room space required.
Disadvantages: 1. Limitations on air flow and filtration levels
2. Smaller compression and hence higher kW/ton
consumption.
3. Operating sound levels can be quite high.
4. Limitations on the amount of fresh air intake.
Cen
tral Plan
t Systems
Central Plant Systems
• Central air conditioning is used for cooling big buildings, houses, offices, entire hotels, gyms, movie theatres, factories etc.
• A central air conditioning system is comprised of a huge compressor that has the capacity to produce hundreds of tons of air conditioning.
• Cooling big halls, malls, huge spaces, galleries etc. is usually only feasible with central conditioning unit
Cen
tral Plan
t Systems
• There is a plant room where large compressor, condenser, thermostatic expansion valve and the evaporator are kept in the large plant room. They perform all the functions as usual similar to a typical refrigeration system. However, all these parts are larger in size and have higher capacities.
• The chilled is passed via the ducts to all the rooms, halls and other spaces that are to be air conditioned.
Cen
tral Plan
t Systems
Cen
tral Plan
t Systems
1. Cooling tower 2. Plant room 3. AHU room 4. Air conditioning room
1) Plant Room:
• The plant room is a important components.
• These include the compressor, condenser, thermostatic
expansion valve and the evaporator or the chillier.
• Piping required to connect these parts
2) Air-Handing Unit (AHU) Room
• The air handling units are installed in the place called air
handling unit rooms.
• The air handling units comprise of the cooling coil, air
filter, the blower and the supply and return air ducts.
Components:
• The chilled water flows through the cooling coil.
• This cooled air passes over the air filter and is passed by the
supply air ducts into the space which is to be air conditioned.
• The air handling unit and the ducts passing through it are
insulated to reduce the loss of the cooling effect.
3) Air Conditioned Rooms:
• These are the rooms or spaces that are to be air conditioned.
• At the top of these rooms the supply and the return air ducts
are laid. The supply air ducts supply the cool air to the room
via one set of the diffusers, while the return air ducts absorbs
the hot return air from the room by another set of the diffusers.
• The hot return air enters the air handling unit, gets cooled and
again enters the room via supply duct to produce air
conditioning effect.
4) Cooling Tower: • The cooling tower is used to cool the water that absorbs
heat from the compressor and the condenser.
• When water flows through these components some water
gets evaporated, to make up this loss some water is also
added in the cooling tower.
• The cooling tower is of evaporative type. Here the water is
cooled by the atmospheric air and is re-circulated through
the compressor and the condenser.
AHU
Cen
tral Plan
t Systems
Cen
tral Plan
t Systems
ADVANTAGES : 1. Noise in rooms is usually reduced if plant room
is away from occupied spaces.
2. The whole building can be controlled from a
central control station. This means that optimum
start and stop can be used .Also time clocks
can bring air conditioning on and off at
appropriate times.
3. Maintenance is centralised in the plant room.
Plant is easier to access.
DISADVANTAGES:
1. Expensive to install a complete full comfort air-
conditioning system throughout a building.
2. Space is required for plant and to run ductwork
both vertically in shafts and horizontally in ceiling
spaces.
3. Individual room control is difficult with central
plant.
Air Conditioning Size
The cooling capacity of room air conditioners is
measured in BTUs, or British Thermal Units, per
hour.
To figure the size unit you need, measure the
space you're trying to cool and find it on this chart.
To estimate square footage, multiply the length of
the room by the width. (A room that's 10 feet by 20
feet, for example, has 200 square feet in it.
To cool this area Size air conditioner
100 to 150 square feet 5,000 BTUs per hour
150 to 250 square feet 6,000 BTUs
250 to 300 square feet 7,000 BTUs
300 to 350 square feet 8,000 BTUs
350 to 400 square feet 9,000 BTUs
400 to 450 square feet 10,000 BTUs
450 to 550 square feet 12,000 BTUs
550 to 700 square feet 14,000 BTUs
700 to 1,000 square feet 18,000 BTUs
1,000 to 1 400 square feet 24,000 BTUs
Table
When looking for the correct size air conditioner, keep these
suggestions in mind, as well:
• If the room is heavily shaded, you can reduce the BTU
capacity by 10%
• If the room is very sunny, you should increase the BTU
capacity by 10%
• If more than 2 people regularly occupy the room, add 600
Btu for each additional person
• If the unit is for a kitchen, increase the capacity by 4,000
Btu/Hr.
Thank You