Ventilation system

1. INTRODUCTION TO VENTILATION
SYSTEM IN BUILDINGS
INTRODUCTION TO VENTILATION
SYSTEM IN BUILDINGS

2. VENTILATION SYSTEM IN BUILDINGS
Definition: is 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.
WHAT IS THE FUCNTION
• Health
• thermal comfort
• Cooling the building structure
http://www.architecture.com/SustainabilityHub/Designstrategies/Air/1-2-1-3-naturalventilation-c
http://www.scribd.com/doc/36277299/Slide-Ventilation-System

3. Health

4. Thermal comfort

5. Cooling the building structure

6. NATURAL VENTILATION SYSTEM
Definition:
is the 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
Natural ventilation occurs in two ways :
1.Pressure differences
2.Temperature difference.
PRESSURE DIFFERENCES
•Air moves from high pressure to low pressure. Speed of air movement depends​​
on the pressure differences
•These types of ventilation are divided into three ;.
a)Window (Pengudaraan tingkap)
b)Roof (Pengudaraan bumbung)
c)Wall (Pengudaraan dinding.)

8. WINDOW TYPE (PENGUDARAAN TINGKAP)
•Window is one of the only several ways to get natural ventilation. Design in terms
of shape, position, size and number of openings will determine the effects of
ventilation.
•Ideally, windows/openings should be placed on all the walls of the building..
•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

9. ROOF. (PENGUDARAAN PADA BUMBUNG)
Convective Flow due to Stack Effect
•One way to ventilate a building that is hotter or colder on the inside than outside is
to use what is known as "stack effect". Because of the temperature difference, the
air inside the building is either more or less dense than the air outside. If there is
an opening high in the building and another low in the building, a natural flow will
be caused. If the air in the building is warmer than the outside, this warmer air will
float out the top opening, being replaced with cooler air from outside. If the air
inside is cooler than that outside, the cooler air will drain out the low opening,
being replaced with warmer air from outside.

10. WALL (PENGUDARAAN MELALUI DINDING)
•Ventilation is obtained by making the opening in the wall, such as fixed louvered,
cantilever and cavity brick
•All these openings allow air into the chamber through the effects of wind pressure

11. TEMPERATURE DIFFERENCES (STACK
effects )
•Air movement caused by stack effect. This effect occurs when there are air
temperature differences within outside and inside . Hot air in the building will rise up
and will be replaced with cold air from outside.
•Rate of air movement is dependent on the :
1. Temperature difference
2. Height
3. The size and position of the air intake opening.

12. ADVANTAGES OF NATURAL VENTILATION
• Reduction in Energy Costs. -it’s estimated that natural ventilation systems can
save a property anywhere between 10% and 30% of the building’s energy
consumption; which in a time when energy bills are constantly increasing is ever
important.
• Little to no maintenance – due to the system requiring no filters, pumps or fans it
requires little to no maintenance; meaning once it has been installed you won’t be
paying out for any other costs anytime soon.
• less noise
DISADVANTAGES OF NATURAL
VENTILATION
• Difficult to control the movement of air.
•Difficult to control temperature.
•Humidity rate can’t be controlled
•Air movement is not comprehensive

13. FACTORS INFLUENCING THE
EFFECTIVENESS OF AIR FLOW
1.POSITION OF OPENINGS ( lower or higher)
1.ARRANGEMENT OF FURNITURE IN ROOM
2.SUHU
3.HUMIDITY rh

14. 1. POSITIONING THE OPENING

15. 1. ARRANGEMENT OF FURNITURE

16. Factors that influence the air flow in the buildings
1.Orientation
Point the main opening / largest towards the wind direction. Wind that comes from
the oblique direction (45 °) can increase the speed and provide more uniform distribution
in the building compared with vertical direction (90 °)

17. 2. Obstacles
Wind speed will increase if there are obstructions (tunnel effect)

18. 3. Cross ventilation
If there are no opening or full of restrictions (obstructions) , air flow will not
be formed. Therefore, opening out must be provided to improve cross
ventilation

19. 4. Location of openings
Openings must be able to provide adequate air to the body level (living zone) at the
height of + 2 m. If the opening on the wall are located at the top, the wind will flow
upward. If the opening are located at the lower part of the wall, the wind will flow
downward to floor . Look at the Malay house openings …….

20. 5. Opening size
Higher speeds can be produced by designing small inlet openings and large outlet
openings.

21. 6. Opening Method
Wind flow in the space are affected by cantilever device and sun shade awnings

22. 7. Tunnel effects
Occurs when there is a large temperature difference between the air inside and
outside the building.
If there are windows or openings, hot air goes up and out through the opening on the
top.
Cold air enters from the bottom to replace the void
This process took place and forms flow in and out naturally

23. MECHANICAL VENTILATIONSYSTEM

24. INTRODUCTION
• Used for applications where natural ventilation is not appropriate
• Employ an electrically fan to provide the necessary air movement
•Ensure a specified air change and the air under fan pressure can be forced
through fillers.
•Circulate fresh air using ducts and fans, father than relying on airflow through
small holes or cracks in a home’s walls, roof or windows.

25. WHY WE USED MECHANICAL VENTILATION?
1.Internal rooms.
2.Large closely populated rooms more than 50 people such as in shopping
complex, office, hall
3.Where close control of environment is required; Hospital
4.Where natural ventilation is impossible as windows cannot be opened of
external atmospheric population or noise especially near to industrial arears.
5.In tall building where wind and stack effects with natural ventilation
impracticable…..
6.Extract ventilation to deal with fumes, smells and odors
7.Heat liberation within the room ( i.e. Cooking)
8.Moisture liberation within the room (i.e. bathroom)

28. Mechanical ventilation is a process of exchange
air in buildings using machine assistance.
The Needs :
1.Difficult to get the quantity, quality and ventilation controled.
example: factory, cinema, operation theater ……
2.To control the indoor environments ( thermal, humidity and wind speed)
3.To received adequate air in the buildings
4.Removing excess heat.

29. Type of Mechanical Ventilation..
1.Natural inlet and mechanical extract
2. Mechanical inlet and natural extract
3. Mechanical inlet and extract

36. 1. FAN
- Devices to move air
- Sometimes called air pumps or blowers
- Without fans these are no mechanical ventilation
- Installed in openings in the wall or in an air- conditioning system (AHU room)
- Type a) Propeller fan b) Axial fan c) Centrifugal fan
- Axial fan and centrifugal fan used in heavy duty
- Propeller fan is found in most of the wall mounted ventilation fan units
- Fans move the air either
- a) from the outside to the inside (intake fans or supply fans)
- b) from the inside to the outside ( intake fans or supply fans)
- c) from the inside to the outside ( extract fans or exhaust fans)
- Ventilations fans are required by law for toilets which do not have a direct
opening to the outside air
- Turbine fans located at the roof ventilate the roof to help keep the building
interiors below cool
-

53. KEBAIKAN DAN KELEMAHAN PEREDARAN UDARA
BERJENTERA
KEBAIKAN
1.Peredaran udara dapat dikawal
2.Udara segar boleh ditapis
3.Keadaan lebih selesa
4.Sesuai untuk bilik sever
KELEMAHAN
1.Kos penggunaanya mahal
2.Bunyi bising

54. FAKTOR PERMILIHAN KE ATAS PENGGUNAAN SISTEM
GANTIAN UDARA BERJENTERA
1.Ketidakupayaan gantian udara semulajadi
•Bilik yang terdapat dibawah tanah pada kebisaanya tidak akan mendapat
pergerakan udara secara optimum. Dengan itu jentera perlu digunakan untuk
mendapatkan pergerakan udara.
2.Ruang-ruang yang sesak
• Ruang seperti dewan perhimpunan, bilik darjah dan dapur selalu sesak dengan
orang. Udara cepat menjadi kotor atau panas. Pergerakan udara yang perlahan
akan menjadikan ketidakselesaan bagi , manusia. Udaran berjentera diperlukan
untuk bekalan oksigen, mengawal kenaikan suhu , haba atau kelembapan dan
memelihara kebersihan udara.
3.Mengeluarkan udara kotor lagi merbahaya.
•Gas-gas yang berbahaya seperti karbon dikoksida perlu dikeluarkan secara
segera. Ia akan menganggu kesihatan. Bilik makmal biasanya memerlukan kipas
penyedut untuk megelurkan gas bahaya.
4.Mengeluarkan bauan
•Kawasan yang ramai pengunaa seperti tandas, dewan dan restoran perlu
mengeluarkan bau. Kebersihan udara disitu perlu dijaga.

55. 5. Bangunan Tinggi
• Pengunaan pengudaraan semulajadi tidak sesuai untuk bangunan tinggi. Tiupan
angin yang kuat mendatangkan masalah kepada penghuni. Oleh itu tingkap perlu
ditutup dan penyaman udara diperlukan
6.Kawasan yang sukar mendapat angin
7. Lebihan haba dari semua arah ( pulau panas)
8. Kawalan udara dan suhu
9. Kenaikan taraf hidup

56. 1) JENIS KIPAS
Kipas propellar
Kipas centrifugal
Axial flow

57. 2. ) air-conditioner
Window Air Conditioning
System
Split Air Conditioner
System

58. Packaged Air Conditioners
Central Air System