ventilation & a/c system

This topic explains the importance of ventilation in a building. Identification on types of ventilation and air conditioning system, methods of installation of air conditioning system and its components.

1. TOPIK 3
VENTILATION
IMPORTANCE &
PURPOSE
DEFINITION
METHODS OF FIXED
VENTILATION
-Natural inflow & outflow
-Natural inflow & mechanical outflow
-Mechanical inflow & natural outflow
-Mechanical inflow & outflow
TOPIC 1: VENTILATION & A/C SYTEM
TYPES OF
VENTILATION &
A/C SYSTEMS
-Natural vent.
-Mechanical vent.
TYPES of A/C
SYSTEMS
-Split unit
-Centralize unit
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2. 2
DEFINITION
•the process of "changing" or replacing air in any space to
provide high indoor air quality.
(i.e. to control temperature, replenish oxygen, or remove moisture,
odors, smoke, heat, dust, airborne bacteria, and carbon dioxide).

• Ventilation is used to remove unpleasant smells and
excessive moisture, introduce outside air, to keep interior
building air circulating, and to prevent stagnation of the
interior air.

•Ventilation includes both the exchange of air to the outside
as well as circulation of air within the building. It is one of
the most important factors for maintaining acceptable
indoor air quality in buildings. Methods for ventilating a
building may be divided into mechanical and natural types.
TOPIC 1: VENTILATION & A/C SYTEM

3. 3
PURPOSES OF VENT.
1.Maintain the oxygen content in the area
2.Reduced the carbon dioxide content
3.Controlling humidity in a room.
4.Prevent the heat from the outside
5.Prevent the heat intensity of the machines, lighting
and occupants
6.To maximize heat loss in space
7.Eliminate odor and dirty air content
8.Provides freshness and convenience
9.Cooling the temperature in the area.
TOPIC 1: VENTILATION & A/C SYTEM

4. TYPES OF VENTILATION SYSTEMS
1. NATURAL



2. MECHANICAL


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a)Wind driven ventilation
b)Pressure driven flows
c)Stack vent / Stack effect
TOPIC 1: VENTILATION & A/C SYTEM
a)Natural inflow & outflow
b)Natural inflow & mechanical outflow
c)Mechanical inflow & natural outflow
d)Mechanical inflow & outflow
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5. NATURAL VENTILATION
•process of supplying and removing air
through an indoor space without using
mechanical systems. It refers to the flow
of external air to an indoor space as a
result of pressure or temperatures
differences.
•There are three types of natural
ventilation occurring in buildings:
–wind driven ventilation,
–pressure-driven flows,
–stack vent/ stack effect
natural vent. is generally impractical for
larger buildings, as they tend to be large,
sealed and climate controlled specifically by
HVAC systems. (heating, ventilation, and air
conditioning)
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6. NATURAL VENTILATION
•Occurs when the air in a space is changed with
outdoor air without the use of mechanical systems,
such as a fan.
•Most often natural ventilation is assured through
operable windows but it can also be achieved
through temperature and pressure differences
between spaces.
•Open windows or vents are not a good choice for
ventilating a basement or other below ground
structure.
•Allowing outside air into a cooler below ground
space will cause problems with humidity and
condensation.
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7. NATURAL VENTILATION
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a)WIND DRIVEN VENTILATION
•Wind driven ventilation depends on wind behavior, on the
interactions with the building envelope and on openings or
other air exchange devices such as inlets or chimneys.
•Occurs when the wind blows toward the house or building and
create pressure.
The front surface of the wind is in the high-pressure or positive.
Surface wind hedges is in low or negative pressure.
Air moves from high pressure zones to low pressure zones.
The higher rate of wind speed will be even more marked
difference in air pressure.
Ventilation through windows, roofs and walls.
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8. NATURAL VENTILATION
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Wind-induced ventilation uses pressures generated on the building by
the wind, to drive air through openings in the building. It is most
commonly realised as cross-ventilation, where air enters on one
side of the building, and leaves on the opposite side, but can also drive
single sided ventilation, and vertical ventilation flows.
Figure : For a given total area,
ventilation is improved when openings
are well distributed horizontally and
vertically. This is because the openings
are more likely to be at different
pressure. It also leads to better
distribution within the room.
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9. NATURAL VENTILATION
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b)PRESSURE DRIVEN FLOWS
Wind pressures are generally high/positive on the windward side of a
building and low/negative on the sheltered side. The occurrence and
change of wind pressures on building surfaces depend on:
 wind speed and wind direction relative to the building;
 the location and surrounding environment of the building;
 shape of the building.

For a building with numerous partitions and openings, it is under
various pressures depending on the relative sizes of the openings and
the wind direction. With large openings on the windward face, the
building tends to be under positive pressure. The reverse is true if
the openings are smaller than those downstream.

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10. NATURAL VENTILATION
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Figure : Air flow around a building
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11. NATURAL VENTILATION
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c)STACK VENT / STACK EFFECT
• Stack effect is temperature induced.
• When there is a temperature difference between two adjoining
volumes of air, the warmer air will have lower density and be more
buoyant thus will rise above the cold air creating an upward air
stream.
• Forced stack effect in a building takes place in a traditional fire
place.
• Passive stack ventilators are common in most bathrooms and other
type of spaces without direct access to the outdoors.
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12. TOPIK 3
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13. TOPIK 3
Comparison of stack effect in the seasonal climate.
During the summer season (see Figure), the reverse occurs when
indoor temperature is lower than outdoor temperature. Figure shows
stack effect that may occur in different forms of buildings, including a
building with no internal partition, a building with airtight separation of
each storey, and an ideal building with vertical shafts and horizontal
openings.
TOPIC 1: VENTILATION & A/C SYTEM
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14. TOPIK 3
Combination of wind pressure and stack effect ventilation.
Occurs when strong wind flows towards the opening. The internal
air will be pushed out through chimneys or atrium. Therefore the
contaminated internal air will be replaced with fresh air.

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15. TOPIK 3
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16. TOPIK 3
ADVANTAGES OF NATURAL
VENTILATION
1. Does not require any mechanical appliances.
2. Non operational cost.
3. Non maintenance cost for the appliances/
equipment.
4. Silent processes.
5. Combination benefit of ventilation, lighting
and esthetical value.
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17. TOPIK 3
DISADVANTAGES OF NATURAL
VENTILATION

1.The system is uncontrolled:
…in terms of speed & distribution
…high rise building received strong velocity
thus windows should be kept closed.
…slow wind velocity during rainy season

2.Internal temperature cannot be monitored:
…difficult to achieved the required human comfort
temperature.

3.Rate of air humidity is uncontrolled :
…depends on the existing external humidity
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18. TOPIK 3
DISADVANTAGES OF NATURAL
VENTILATION

4.Uneven uniform distribution :
…ventilation rate depends on sizes of opening.
…distribution is maximum at the area/space
nearby the opening.
…low ventilation rate for rooms further inside a bldg.

5.Quality of fresh & clean wind cannot be assured
…maybe contaminated from the external harmful
element such as smoke and dust.
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19. MECHANICAL VENTILATION
•through an air handling unit or direct injection to a
space by a fan. A local exhaust fan can enhance
infiltration or natural ventilation, thus increasing the
ventilation air flow rate.
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Typical AHU components:

1 - Supply duct
2 - Fan compartment
3 - Flexible connection


4 - Heating and/or cooling coil
5 - Filter compartment
6 - Return and fresh air duct
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20. TOPIK 3
a)NATURAL INFLOW & OUTFLOW
b)NATURAL INFLOW & MECHANICAL OUTFLOW
c)MECHANICAL INFLOW & NATURAL OUTFLOW
d)MECHANICAL INFLOW & OUTFLOW


METHODS OF MECHANICAL
VENTILATION
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21. Winds enter the room naturally without assistence
from appliances.
Internal air is force out with fan which normally fixed
at the building component such as :
–roof
–wall
–window
Suitable for factory, workshop, assembly hall,
bathroom, kitchen and etc.
The system helps to prevent the contiminated/foul
air from entering the adjacent space.
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1.NATURAL INFLOW & MECHANICAL
OUTFLOW / sistem sari
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22. TOPIK 3
NATURAL INFLOW & MECHANICAL OUTFLOW

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23. •External air brought into the building by
application of suction fan.
•Consumed indoor air will exit naturally through
the openings which positioned at the lower level
of the building.
•The methods allows the external air to be filtered
before entering the internal space.
•Recommended for small factory building,
offices or boiler house.
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2. MECHANICCAL INFLOW & NATURAL
OUTFLOW / sistem bekal
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24. TOPIK 3
MECHANICCAL INFLOW & NATURAL OUTFLOW
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25. •External air enters and exit the internal space by
applications of mechanical fan.
•The building need to be properly concealed from
noise, excessive air pressure and temperature.
•Internal air distribution and temperature can be
control. External air can be filtered before consumed
and the replenishment process could be done
affectively.
•Recommended for internal spaces with problematic
air circulations – i.e: operation theater, cinema or
spaces which required a controlled internal
temperature - i.e: laboratories etc.
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3. Mechanical Inflow & Outflow (sistem seimbang/
kombinasi bekal & sari)
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26. TOPIK 3
Gambarajah sistem seimbang
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27. TOPIK 3
4. Plenum System
(kombinasi bekal, sari dan seimbang)
•Comprises of air filter, heating and cooling
element into the system.
•The air distributed through ducting system
positioned inside the building.
•Applicable for internal spaces which required a
cooled or hot controlled temperature such as –
hospitals, warehouses, chiller room ,
laboratories etc.
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28. TOPIK 3
Gambarajah sistem plenum
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Distribution
to internal
space
Distribution
to internal
space
Air suction
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29. TOPIK 3
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REQUIREMENT
FOR MECHANICAL
VENT…WHY?
Natural system is
ineffective in terms of
quantity and quality
Building/space location
makes natural vent
impossible – i.e: basement
space or hidden corner
Types of building usage or space
requirements skycrapers, needs
for convenience congested space
(smell, odors) or needs for
temperature control
Safety from surrounding
environment- such as from
contaminated air, hazardous
noise level, light or glare.
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30. TOPIK 3
TOPIC 1: VENTILATION & A/C SYTEM
Advantages
Disadvantages
Mechanical Vent.
a) Even air distribution
b) Filtered air (Q )
c) Controlled of humidity and temperature
d) Minimized entrance of hazardous air
a) involved initial, operation & m’ce cost
b) extra space to allocate equipment's
c) increase noise level (sound buffer)
d) required power supply & backup systems
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31. AIR CONDITIONING SYSTEMS
•Air conditioning (often referred to as A/C, AC) is
the process of altering the properties of air
(primarily temperature & humidity) to an occupied
space to improve thermal comfort and indoor air
quality.
•air conditioning can refer to any form of technology
that modifies the condition of air (heating, cooling,
(de-)humidification, cleaning, ventilation, or air
movement). In construction, such a complete
system of heating, ventilation, and air conditioning
is referred to as HVAC.
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32. Window unit
Split unit
TYPES OF A/C
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33. TYPES OF A/C
Packaged terminals
Centralized System
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34. SPLIT UNIT
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COMPONENTS
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35. SPLIT UNIT
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COMPONENTS

36. SPLIT UNIT
TOPIC 1: VENTILATION & A/C SYTEM
APPLICATIONS
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37. SPLIT UNIT
TOPIC 1: VENTILATION & A/C SYTEM
APPLICATIONS
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38. SPLIT UNIT
TOPIC 1: VENTILATION & A/C SYTEM
APPLICATIONS
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39. SPLIT UNIT
TOPIC 1: VENTILATION & A/C SYTEM
APPLICATIONS
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40. SPLIT UNIT
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INSTALLATION
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-Above the door

-Minimum installations set back.

41. SPLIT UNIT
TOPIC 1: VENTILATION & A/C SYTEM
INSTALLATION
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-Wall mounted.

-Supported by metal plate

42. SPLIT UNIT
TOPIC 1: VENTILATION & A/C SYTEM
INSTALLATION
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-Supportive metal bracket.

43. SPLIT UNIT
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ADVANTAGES

i.Easy installation. Since there is no ductwork to
install, the units are easy to set up. The indoor unit
can be up to 100 feet away from the outdoor
condenser, yet the only space required is a small hole
in a wall for the copper tubing and control wiring. The
condenser unit can even be positioned on a flat
section of roof if available.
ii.Easy maintenance. Split air conditioning systems are
easy to maintain. They have washable filters and
require only routine cleaning periodically. Outdoor
units are designed for easy access for maintenance
and repair.
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44. SPLIT UNIT
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ADVANTAGES

iii.Quiet operation. The indoor units of these systems
are typically quiet enough for libraries, classrooms,
boardrooms, and bedrooms. The outdoor components
can be installed under a window or near a patio
without disturbing anyone.
iv.Heating capability. Most split air conditioning units
provide “climate control” with additional heating as
well, so you can live and work comfortably year-
round.

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45. SPLIT UNIT
TOPIC 1: VENTILATION & A/C SYTEM
ADVANTAGES

v.Cost effectiveness. Work well in situations where
rooms only need to be cooled at certain times, i.e;
living rooms during the day and bedrooms at night.
Effective distribution may save cost & energy, since
smaller fan motors are used and individual units run at
different times.
vi.Simple control. Most units come with a remote
control, as well as a wall mounted thermostat, and
temperature control is easy and convenient.
vii.Attractive design. Instead of a big, clunky window
unit you have air conditioning units that blend well into
indoor decor. There is no need to block your windows,
either.
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46. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
COMPONENTS
Central air conditioning plants are used for applications
like big hotels, large buildings having multiple floors,
hospitals, etc- where very high cooling loads are
required.

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 perform all the
functions as usual similar to a typical refrigeration
system. However, all these parts are larger in size and
have higher capacities.
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47. CENTRALISE SYSTEM
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COMPONENTS












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48. CENTRALISE SYSTEM
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There are two types of central air conditioning plants or
systems:

1) Direct expansion or DX central air conditioning
plant: In this system the huge compressor, and the
condenser are housed in the plant room, while the
expansion valve and the evaporator or the cooling 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 over
the cooling coil. 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.
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49. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
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50. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
2) Chilled water central air conditioning plant: 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.
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51. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
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52. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
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53. CENTRALISE SYSTEM
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INSTALLATIONS

The installation process will be different for each job,
depending on your HVAC contractor, the type of unit
you purchase and your home's unique needs and
features.
However, there are some basic procedures you can
count on when having your system installed.
Here are some general installation steps that you
should expect from your contractor:

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54. CENTRALISE SYSTEM
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INSTALLATIONS
i.Dismantle and haul away existing air conditioner materials,
and clear all related debris before starting the new install.
ii.Acquire proper permits and schedule required inspections
from the city where you live.
iii.Install new ductwork (if indicated in proposal), or prepare
existing ductwork for use with the new system.
iv.Properly position and place outdoor air conditioning unit.
v.Make proper, safe connections & determine the correct
sizing for the electrical and refrigeration lines and piping.
vi.Install a new thermostat or reuse the existing thermostat.
vii.Charge and start the new system according to manufacturer
specifications.
viii.Conduct a post-installation check or inspection before final
inspection.

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55. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
INSTALLATIONS

Consideration of installation started from initial design
stage taking in factors such as:

Contractor - assessment of the home to determine the
appropriate size for the unit(s). This might also be the
individual who installs the actual a/c unit;

Subcontractor - this might be the licensed individual to
perform electrical service (if the HVAC contractor is not
a licensed electrician), or it could be the individual(s)
who run ductwork and handle the many materials;

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56. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
INSTALLATIONS
Labour - if the contractor or subcontractor do not
complete all of the installation work on their own, there
will usually be at least one laborer hired to assist; and

Material - from the a/c Freon refrigerant, the tanks,
recovering machine, and the nitrogen, the costs
associated with a central air conditioner involve many
materials.
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57. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
ADVANTAGES:
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58. CENTRALISE SYSTEM
TOPIC 1: VENTILATION & A/C SYTEM
DIS-ADVANTAGES:
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59. TOPIK 3
TOPIC 3: VENTILATION
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