Energy Efficient Ventilation System

TAYLOR’S UNIVERSITY | SABD | ENVIRONMENTAL SCIENCES AND SERVICES (BLD61104AC199)
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GROUP NUMBER : Group 11
TEAM MEMBERS : 1) Kho Chen Yong - 0335009
2) Ong Yih Xian - 0335006
3) Kang Ying Hong - 0334177
4) Choy Jin Hao - 0327440
5) Kelvin Yeo Chung Han - 0330277
6) Muhammad Mushtafa - 0334176
SCHOOL OR FACULTY : School of Architecture, Building and Design
FACILITATOR : Mr Leong Boon Tik
TITLE : Ventilation

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TABLE OF CONTENT
1.INTRODUCTION TO VENTILATION
2.INSTALLATION PROCESS OF PSV
i) Straight duct ventilation.
ii) Installation with bends.
3.MANAGEMENT SYSTEM OF PSV
4.THE ADVANTAGES AND DISADVANTAGES OF PSV
5.CASE STUDY: FINDING AND EXPLANATION OF EASTGATE
Biomimicry
Eastgate Ventilation Process.
Estimate Fresh Air supplied.
6.POSSIBLE PROBLEMS OF THE SYSTEM
7.RECOMMENDATION FOR FUTURE IMPROVEMENT
8.LEARNING OUTCOME - GROUP REFLECTION.
9.REFERENCES
10.BIBLIOLOGY
11.APPENDICES.

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1. INTRODUCTIONTO VENTILATION.
Ventilation can be described as intentional introduction of ambient air into a space
and is mainly used to control indoor air quality by diluting and displacing indoor pollutants.
Ventilation rate is the rate at which air within a building is replaced by fresh air. It can also be
expressed as number of times the volume of air within a space is changed in one hour and the
rate of air change in volume and time per second. Ventilation is necessary to provide a
healthy and comfortable internal environment for the building’s occupants. The main task of
ventilation is to remove polluted indoor air from a building and replace it with ‘fresh’ outside
air. Ventilation can also serve other roles such as providing an air supply to open-flued
combustion appliances and to form part of an integrated strategy to provide thermal comfort
and control summertime overheating. There are different types and sources of pollution
within the home such as moisture from washing and cooking, carbon monoxide and oxides of
nitrogen from combustion alliances, smoking, volatile organic compounds from aerosols and
formaldehyde found in some furniture, allergens from house dust mites, CO2 from humans
and also combustion appliances, environmental tobacco smoke and odours from cooking,
bodies and pets.
Moisture is probably the most significant of these because of the high rates generated
by activities such as cooking and bathing, and because of the problems associated with
condensation and mould growth. Research has shown that if relative humidity levels exceed
70 per cent for prolonged periods, there is a high probability that the condensation occurring
on cold surfaces will lead to mould growth. A ventilation rate of between 0.5 and 1.5 air
changes per hour for the whole dwelling will usually be sufficient to control condensation.
These levels of ventilation are generally sufficient to control many other indoor pollutants
such as combustion products generated by gas cooking, VOCs from building and consumer
products, body odours. Although research is still on-going on the most effective strategies to
control house dust mites and allergen production, again the reduction of indoor humidity
levels is a key factor.
An efficient ventilation system must meet the following requirements which are
establishing hazard-free air quality, satisfying user comfort, being energy efficient and cost
effective. The air temperature and relative humidity are major factors for maintaining comfort

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and good health. Extreme conditions can cause discomfort, promote the spread of
microorganisms which cause disease and can seriously irritate the respiratory systems.
There are two types of ventilation which are natural and mechanical ventilation.
Natural ventilation depends on wind direction and pressure or the stack effect of warm air
rising within a building, while cooler air exists outside. Natural ventilation is uncontrolled
inward and outward leakage through cracks and interstices known as infiltration and
exfiltration. Infiltration and exfiltration are caused by the weather and other pressure-
difference forces exerted on a building. Infiltration Air is the unintentional and uncontrolled
entry of outdoor air into an enclosed space. Infiltration occurs through cracks in the building
envelope and due to pressure differences between inside and outside. The outdoor air entering
through open doors and windows is considered infiltration although the purpose of opening
the door or window might be ventilation. Infiltration occurs mainly in winter when the air
outside is colder and heavier than the air inside. It depends on wind velocity, wind direction
and the airtightness of the building envelope. In the case of high-rise buildings the stack
effect also causes infiltration. Mechanical ventilation is ventilation provided by electric fans.
These fans are often part of an air-conditioning system and may drive the supply airflow, or
both the supply and exhaust airflows. Mechanical ventilation or air-conditioning system is
suitable for Internal rooms, large closely populated rooms where distribution of natural
ventilation is inadequate, rooms where volume per occupant is too low for efficient natural
ventilation, controlled environment, tall buildings for stack effect and smoke control.
2.INSTALLATION PROCESS.
STRAIGHT DUCT INSTALLATION.
Rigid System:

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a. Measure the length of duct to be used carefully, to ensure that the outlet terminal
will be level with, or higher than, the ridge.
b. Use preformed pieces to make any joints to give stability to the duct.
c. Where the duct penetrates the roof covering, seal with a traditional or prefabricated
flashing.
e. Ensure that the vent cowl (where provided) is suitably secured to the duct.
Flexible System:
a. Carefully measure the length of the duct to be used to fit between the inlet grille
and the roof slope so that the duct does not sag or wrinkle. The duct material
should be fully extended but should not place any strain on terminals or fittings.
b. Use a rigid duct for that part of the duct outside of the roof to provide stability. It
should start from far enough inside the roof space to give adequate support, and
extend to the height of the ridge or above.
c. Where the duct penetrates the roof covering, seal with a traditional or prefabricated
flashing.
d. The flexible ducting should be securely joined to the rigid section by means of a
jubilee clip and water proof tape, ensuring that there is no restriction of cross-
sectional area.
e. Support the duct where it passes through a room or the attic by attaching it to a
suitable wall or a wooden strut, in such a manner that it will not be squashed or
distorted.
INSTALLATIONS WITH BENDS:
Rigid system:
a. Use preformed bend sections so that any angle formed with the vertical is 45o or
less.
b. Support the duct so that it does not place undue strain on the join with the ridge
terminal.
c. Ensure that the roof structure is suitably strengthened to allow for installation of the
ridge terminal.

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Flexible system:
a. Cut ducting to approximately 300 mm longer than the distance between the inlet
grille and the outlet terminal to provided enough material to make smooth bends
for connection to the terminals.
b. Where there is a straight section of duct, (i.e. passing through an upstairs room),
support it by attaching it to a suitable wall or a wooded strut so that it will not be
squashed or distorted. In the attic, because the duct bends, it should be supported
on a wooded strut that is fixed securely at both ends. The duct should be allowed to
curve gently at each end to attach the inlet grille and ridge terminal.
3. MANAGEMENT SYSTEM.
For the maintenance of passive stack ventilation system, this system requires very
little maintenance. A periodic check of the roof terminal and of any ducting that is accessible
should be enough to maintain the structure of the system. Cleaning the grilles, especially the
one in the kitchen, is essential to ensure that there are no restrictions to air flow up each stack.
The primary causes of blockage are built-up dust and grease in the tines of the grille.
There are criteria for establishing energy efficiency of the passive stack ventilation
system. Passive stack ventilation systems are intrinsically energy saving, in that they simply

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work on the wind and stack effects and consume no electricity. However, none of the heat
loss through ventilation is recovered. The good practice standard is met by following the
relevant national standards and regulations. In addition, to minimise heat loss, a good practice
standard PSV system should have humidity-sensitive duct inlet grilles. To ensure a good
balance between indoor air quality and energy use, the controls should be set such that they
always meet the minimum air flow requirements under building regulations and guidance and
are fully open when the humidity in the room is greater than 65 percent. A simple passive
stack ventilation system is not recommended for best practice standard. This is because the
system is reliant on weather conditions such as under-ventilating in warmer weather, and the
high level of airtightness required to achieve this standard.
The term ‘assisted passive stack’ can be applied to two types of system, both of which
are acceptable for best practice standard. The first one is where the system is set up such that
flow in the duct is automatically augmented by an extract fan only when required. The other
one is where the system is set up such that an extract fan is constantly running in the duct.
4. THE ADVANTAGE AND DISADVANTAGES OF PASSIVE STACK
VENTILATION (PSV)
The advantages of passive stack ventilation(PSV) is that it can improve the air quality
of the building. This is because it uses natural air as a ventilation. Natural air from the outer
building into the building which improve the air quality. Not only that, passive stack
ventilation can also improved ventilation in the home as it uses a combination of cross
ventilation, buoyancy(warm air rising) and venturi(wind passing over the terminal causing
suction) effect. Other than that, it has a silent operation as it does not require any machine to
operate which also causing it to be maintenance free. Next, passive stack ventilation has no
direct cost associated with the system as no electrical connection. Hence, causing it to be
energy saving and environmental friendly.

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On the other hand, the disadvantage of passive stack ventilation is that the existing
house layouts can make it difficult to accommodate vertical ducting from ground floors.
Besides that, as low pressure differences are involved, systems are more sensitive to proper
installation and must be installed correctly to ensure that design performance is achieved.The
third disadvantage is that the air flow through a passive stack is weather dependant . In
particular, additional ventilation may be required(e.g. opening of window) during warmer
weather.
5. CASE STUDY: FINDING AND EXPLANATION

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A photo of the Eastgate Centre, Harare, Zimbabwe
Ventilation is a vital system within building as stated in the Uniform Building-by-law
,1984. One observation on cost-efficient ventilation can be seen within complex ventilation in
Eastgate Centre in Zimbabwe. Mick Pearce, a renowned architect, is responsible for such
unique and interesting design for the ventilation because of one challenge he had to faced.
The challenge was to overcome the resources limitation as well as budget. Mick Pearce,
solved his problem by investigating nature’s adaptable ability and involve biomimicry over a
unique construction by the termite species called, odontotermes obesus, which builds massive
cathedral-looking mound. These mound acts as air conditioner supported by a long-accepted
but debunked proposal by an entomologist Martin Lüscher, and Mick Pearce took interest in
the concept and apply this theory to the test in his construction.
5.1 Biomimicry
Mick Pearce, as an architect had to uncover the solution to ensure the entire eastgate
centre offices were constantly ventilated and cooled at minimum. As Harare, Zimbabwe face
fluctuating temperature even for a subtropical highland country, Mick Pearce has to wonder

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how would animals survive in such tropical climate. Mick Pearce then took interest in one
skillful animal along with brilliant characteristic of a plant.
5.1.1 The great termite.
The termite are the most feared creatures in terms of their annoyance in the world of
construction. But their although they are create havoc and destroying numerous wooden
construction, they are master builders, in fact most termite that lives in Zimbabwe builds
mound that keeps stable temperature within the termite nest. Termite mound can reach more
than 2-3 meters tall, as it acts as cooling shafts for the entire colony. The method of releasing
stale hot air is the termite genius architecture of producing holes around the mound, as they
harness the air, the wind that blows cold air in on one side, takes out the hot air from the other
side of the mound where the holes acts as suction, sucking out the hot stale air from the
metabolism of the colony. Termites can not live degree temperature of 30°C or else they will
die.
The mound is known to be a climate control design to maintain stable internal
environment. These control is done where the mound wide side facing the east and the west,
which uses the sun as a mechanism for temperature regulation.
5.1.2 The prickly cactus.

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A unique and fascinating characteristic of the Eastgate Centre at Zimbabwe is the
jagged prickly edges and greeneries that aid the north and south façade temperature balancing
as further investigation on the cactus in the dessert capability to survive such climate is not
because of its storage capacity for rain water but also needle that acts as additional layer for
heat loss. The imitation of the cactus has lead Eastgate Zimbabwe to save energy cost by
10%. The concrete “needles” , which in fact, concrete has thermal capability, so usage of
concrete was crucial in this heat loss to happen. Thus this lead to a great cooling phenomenon
on the offices.
5.2 EastgateVentilation Process.

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Picture of the entire ventilation system within Eastgate Zimbabwe.
Mick Pearce’s ventilation imitation on the termite mound is rather unique, as he has
few tweaks over the innovative design on cathedral mound made by odontotermes obesus.
Mick Pearce made two big vents below the office building, as shown in the diagram. The
low-power fans pulls the air from the night, below the atrium, into the vent and cools the
entire office by having air pushed upward into all the office rooms. As the cool air enters the
room, the cool night air passes through hollow shafts that enters the room, colliding into what
to be known as “concrete teeth that acts as thermostore” (Pearce, 2015). These cold concrete
teeth will help in cooling the air in the morning and afternoon which comes in through the
same place. Although, the room will drop down to 20°C and remain constant throughout the
night, the room will lose its coldness due to several reasons. One being combustion that occur
within people, and the other reason is the machines and computers that generates heat due to
system overheating or etc in the morning. Moreover the wind is also guided during the
afternoon and evening through the turbine “pulling” in and as afternoon and evening air
passes through the thermostore concrete teeth, it cools down and this regulates the
temperature of the offices as usual.

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Ventilation located within the room and how to simulates similar to the termite nest
In addition, Ove Arup and Partners,an engineering branch, suggested Mick Pearce a
good solution to improve ventilation cooling effect which was having laminated window with
heat-reduction film. Mick Pearce also used overhung for eliminating heat rays into the
building. The building also has prickly surfaces which provide a bigger surface area for heat
loss to occur in the night. With this, the entire 7 floors of office is cool and efficient. The hot
air that is accumulated throughout the day will be directed into the hot-air chamber above the
entire building, that is directly connected to the funnel that release the heat through a
chimney specialized in using temperature and wind speed to remove hot air just like Passive
Stack Ventilation, increasing velocity of heat loss rapidly via small gaps shaped top to
harvest wind-driven energy. This model has help Mick Pearce save cost in budget on
construction as well as saving up to 35% total energy compare to HVAC ( Heating,
Ventilation and Air Condition) buildings in Harare.
5.3 Estimate Fresh Air Supplied.
This report has acquired data on the air change in Eastgate Zimbabwe, and also obtain
the size of the offices in total as well, leading to a amazing discovery on the fresh air
supplied. Here is the calculation :
AIR CHANGE RATE:
_______________________
10 air change rate in the night

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2 air change rate in the morning.
_______________________
Office size: 26999.946m^2 x 3m(height)
= 80,999.838m^3
Q =nV
Fresh air supply estimately
Night : 10 x 80,999.838m^3 =809,990.838 / hour.
Morning : 2 x 80,999.838m^3= 161,999.676 /hour
The data logger graph shows that in average conditions covering ten months of the
year 3°C of cooling between outside and inside temperature is achieved as shown in the
diagram above provided in the home website of Mick Pearce (Pearce, 2016). Ideal cooling is
accomplished when the outer night temperature falls underneath 20°C. At the point when
20°C is surpassed during the evening; primarily because of overcast cover (which anticipates

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proficient warmth radiation back to space), and when the next day is clear particularly in
October or November the workplace temperature remains genuinely warm.
In conclusion, we can see that the ventilation of Eastgate Zimbabwe fresh air change
is unique and it just works because of this remarkable genius design by Mick Pearce and his
effort to ensure efficiency. The owners of Eastgate have saved $3.5 million because of the
use of natural ventilation and this has trickled down to the tenants who are paying 20 per cent
less rent than occupants of surrounding buildings.
6. POSSIBLE PROBLEMSOF THE SYSTEM.
During the construction and planning process of the ventilation system of the Eastgate
Centre, Mike Pearce ran into some problems the system because, it wasn't just that Eastgate
Centre were the only building in the world that was using this system, the complexity of the
system was also not helpful to the situation.
Some of the problems and difficulties faced by Mike Pearce and his team are, firstly,
he had to find a way to make a ventilation system that is economical and eco friendly which
during early 1990s. It was an even harder task because he wanted the building to have the
same comfort level as an air conditioned building. He had to find a way to keep the building
that was located in the southern part of Africa below 20 degrees celsius.
Secondly, the uncertain and unpredictable Zimbabwean weather really affects the
system and the reason is that the system that Mike Pearce designed really depended on the
outside weather since he did not want to use an air conditioned system and therefore the
weather played a crucial role in the efficient operation of the whole structure. Examples of

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the significance of the building needing calm and cool weather is that the building cools off
during the night and for this to occur efficiently the weather outside has to be below 20
degrees celsius and considering the building uses the method of fractal cooling to cool off,
random changes in wind speed would mean that some days the building would be cooler than
others.
Thirdly, for this system to work well, resources have to be imported from different
countries because Zimbabwe did not have some of the materials needed in order to construct
this ventilation system. This meant that the overhead costs of the building were quite high
considering the currency exchange at the time was not in favour of Zimbabwe.
Fourth, for the system that Mike Pearce designed to operate without any problems,
they had to hire an well known engineering firm in addition. The engineering firm also gave
Mike Pearce rules for him to follow on the construction of the building. This meant extra
costs and extra time because Mike Pearce had to plan out the construction of the building
according to these rules and this took a lot of time to do.
7. RECOMMENDATION FOR FUTURE IMPROVEMENT.
Eastgate Centre has a flawless system per say, when it comes to eco-friendly
ventilation, although there are few recommendation that could slightly enhance the building
ventilation as a whole.
Increasing exposure - heat reduction significantly increase.
As stated by Mick Pearce, the purpose of the design of having the building have a
prickly surface is to better increase in emitting out heat from the building through heat loss
via concrete of the office. By increasing the size widely for the prickly surface of the
building, heat loss would also increase. Although labour is required throughout the process, it
will benefit it for the long-run as temperature does tend to fluctuate throughout the years due
to global greenhouse effect.
Have better machineries and computers.
One of the factor that causes the heat to increase is the computer and machineries that
are overclocking their capability as when electrical energy passes through the CPU or

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blocked inside, produces heat energy. Thus, a better CPU and RAM used for the computers
will highly benefit in the air coolness in the room. Getting newer and efficient PC would also
benefit in terms of work efficiency in the office, leading to work being accomplished early
too. In addition, having workers in the offices to constantly keep their computer files well-
managed and avoid unnecessary items in the PC to avoid overheating of stuff.
8. LEARNING OUTCOME
All in all, the knowledge and experience that have been gained throughout this
assignment is on ventilation and the case study of the Eastgate Centre in Harare that was built
by Mick Pearce. This report has given a broader view on the basis of ventilation and more
insight on passive stack ventilation. This report also relates passive stack ventilation with
Eastgate Centre in Harare as a case study. This report has identify the possible problems of
this flawless system by examining during the construction phase of this project. From there,
this report aims to also provide recommendation towards this case study for future
improvement as to boost strength of this such case study.
As a team, we have accomplished our understanding in the topic of ventilation by
working out together in this assignment. In addition, the very core of achieving completion
for this assignment is the teamwork that was shown by every individual in the group, not
neglecting their work and striving to finish it soon as possible. Not only was there teamwork,
but also the immense time management, ensuring things are done in such a short time that we
had, and came out with a positive result. Throughout the assignment, the team have overcome
obstacles such as paving time and show relevant and world-relating issues to enhance our
learning curve on ventilation. The team would firstly thank the friends and family who has
help us in our times of need throughout compiling this assignment and a huge grateful thanks
to Mr.Leong Boon Tik who has provide us much insight as well correcting and rebuking our
presentation and our assignment report that we have presented. With that, the team would like
to end this report in hopes that this report will give others who read this a spectrum of
understanding and appreciation over the research that we made, thank you.
9. REFERENCES
Author, A. A. [Screen name]. (year, month day). Title of video
[Video file]. Retrieved from http://xxxxx

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Building Construction (2015) Eastgate Mall [Video file] Retrieved from
https://www.youtube.com/watch?v=VIKYjriWgiY
Johnson And Starley (1998) Passive stack ventilation users installation guide Retrieved May 27, 2018,
from http://www.johnsonandstarley.co.uk/downloads/zz1012.pdf
K.J., K. (2018). [online] Envirovent.com. Available at:
https://www.envirovent.com/images/uploads/files/GPG268-Energy-efficient-ventilation-in-dwellings(1).pdf
[Accessed 18 Jun. 2018].
Lookaside.fbsbx.com. (2018). [online] Available at: https://lookaside.fbsbx.com/file/1.%20Ventilation%20-
%201.pdf?token=AWyQpOQKj_vvNo0Sw7iYyvB6970Sb-RbQ3PHe9hqkKG-
ohHTRF3KOAJpXV5EKac_Q9GY5xvcsQq6IdXHFxyQdh0vBDgpKBD170hvsQTQhB3e_DzQYF8t2iemKoP
rfNpf4TFVNySq0eSQDzv8OO-MZUFin-a5iMERj3BPer001VCAlQ [Accessed 18 Jun. 2018].
Mick Pearce Architect. (2016). Retrieved May 25, 2018, from
http://www.mickpearce.com/CV.html
National Geographic (2018) See How Termites Inspired a Build that can cool itself [Video file]
Retrieved from https://www.youtube.com/watch?v=620omdSZzBs&t=135s
10. BIBLIOLOGY
ABCScienceOnline (2014) Termite Air Conditioning [Video file] Retrieved from
https://www.youtube.com/watch?v=GLo04FWl1yA&t=120s
M. G. (2017). PROJECT: EASTGATE [Web log post]. Retrieved May 30, 2018, from
https://cpb-us-
e1.wpmucdn.com/blogs.uoregon.edu/dist/9/10058/files/2017/11/greenfieldmegan_69766_444
0791_Biomimicry-presentation_reduced-1-1qf73rd.pdf
Nguyen, S. (2015, October 20). Termites' Cathedral Mounds. Retrieved May 29, 2018, from
https://harvardmagazine.com/2015/11/termites-cathedral-mounds

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