Thesis Journal by Adrian Chu Sin Chung

TROPICAL SUSTAINABLE LIVING: Enabling educa on through design and architecture in Mauri us

Research Supervisor: Dr. Dominique Hes

Adrian Chu Sin Chung 332874 Design Thesis Semester 2, 2013

TABLE OF CONTENTS

INITIAL THESIS PROPOSAL BRIEF HISTORY OF MAURITIUS MOTIVATIONS EXISTING CONDITIONS

4 6 8 9

PROPOSAL

CONTEXT

SITE SELECTION BAIN BOEUF EBENE CLIMATE ENERGY MODELLING SURVEY RESULTS INTERPRETATION PEDAGOGY

14 15 16 18 19 20 22 23

RESEARCH

CASE STUDY - ENERPOS TROPICAL ARCHITECTURE VENTILATION, SHADING AND INSULATION PLANTS LIGHTWEIGHT BUILDING MATERIALS SYSTEMS THERMAL CHIMNEY THERMAL CHIMNEYS VARIATIONS GEOTHERMAL STACK VENTILATION DESICCANT LIQUID DESICCANT LIQUID DESICCANT AND DESIGN SOLAR PANELS GREEN ROOVES AND WALLS

26 28 29 30 31 32 33 34 35 36 37 38 41 42 43

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MATERIALS BAMBOO sHIGERU BAN HEMPCRETE SEAWEED TIMBER AGRICULTURE AND INDUSTRIES

44 45 48 49 50 52 53

DESIGN PROCESS

INITIAL CONCEPT SKETCHES INITIAL PLANNING INTERVENTIONS INTERIM STAGE GROUND FLOOR PLAN FIRST FLOOR PLAN FEEDBACK AND CRITICISMS POST INTERIM DECISIONS SPATIAL SYNTAX PARTI DIAGRAMS

56 60 64 65 66 67 68 69 70

PROPOSED DESIGN

SITE PLAN GROUND FLOOR PLAN FIRST FLOOR PLAN SECOND FLOOR PLAN SECTIONS ELEVATIONS PERSPECTIVES DESIGN DETAILS DESICCANT SCHEMATIC MATERIAL SCHEDULE REFLECTION REFERENCES

84 85 86 87 88 89 91 96 97 98 99 100

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INITIAL THESIS PROPOSAL

I come from Mauri us, a small island in the Indian Ocean, about two and a half thousand kilometres from the east coast of the African con nent. Mauri us is considered a developing country, and while it is considered one of the most developed African countries, and is quickly catching up with developed countries, it is s ll quite a far way behind in many respect. Un l a few years ago (about 10-15 years), our primary industry was sugar and large por ons of the land use were agricultural lands covered with sugarcane. The bagasse obtained from the sugarcane plants were used as fuels and accounted for most of the country’s energy needs. When sugar was no longer a viable source of income, most of the cane fields got stripped and converted mainly into residen al/large scale development land. The result was that for one there was a sudden boom in the construc on industry (mainly high class residences targeted at wealthy foreign investors in an a empt to boost our tourist industry, which is our primary industry today) and the principal fuel changed from being bagasse to coal. The other sources of energy include hydroelectric (minimal) and gas (mainly for cooking and hot water) and solar is used mainly just for hot water. The main construc on type for most of the buildings, regardless of scale, is just solid concrete. A few of the heritage building da ng back from the colonial period are s ll made of stone and mber, but these are gradually disappearing. Even new buildings made from concrete have improper construc on systems resul ng in spaces that can get very uncomfortable without the presence of ac ve condi oning systems. That brings me to my other point. The climate in Mauri us is mostly a cooling climate. In the lows of winter, only the central highlands get uncomfortably low (and by low I mean rarely below 10). However, in the summer, it becomes very warm, with plumme ng, extremely uncomfortable levels of humidity. As a result, many houses are fi ed with split system air condi oning systems that o en run 24/7 to keep the air condi on to acceptably comfortable levels. People tend to be content using these, and do not make the eﬀort trying to find alterna ve ways of remaining comfortable. I interned at one of the most prominent architectural firms in Mauri us, who were supposed to be leaders in terms of architecture and design. I worked on projects at diﬀerent stages of comple on and realised that sustainable design was definitely not one of their priori es. The only interven ons on most of the projects were shading devices, and even these were not very well thought through, with the exact shadings happening on every façade. This o en led to services engineers specifying very large HVAC systems to make up for a poorly performing envelope. The building I was working in (designed by the firm itself) was basically a glass box with the AC constantly running to keep the temperature low.

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This leads me to yet another point: educa on. The environmental consciousness is not something that ranks par cularly high in the mind of people. There are many organisa ons that try to educate people about the importance of saving energy and water, but to not much effects – when the authori es don’t care much themselves (street lamps le on during the day, leaks in water pipes not taken care of for many days), it does not set the example for the populace. I’ve no ced that in Mauri us, people have a very distorted view of what sustainability is, and many people there consider it ‘expensive and fancy’. This brings me back to the point I men oned previously: people remain conveniently in their comfort zone without trying to make an extra effort to make be er systems, that can lead to more comfortable condi ons. In my proposed thesis, I wish to inves gate the above issues in two dis nct parts. The first part would be to inves gate the different construc on techniques and systems that is available and appropriate to the context of Mauri us. The focus will not be to use the latest, most advanced technologies in terms of sustainable design, but implement reasonably accessible and affordable systems that can be used by local knowledge without too steep a learning curve. The second part of the thesis is to find a way to implement these systems in a way that does not only perform well, but also educate. The demonstra on of the ac ve systems inside a built environment can poten ally show what can be achieved and how it can realis cally be achieved. This might break the barrier that has been holding the local percep on about the real benefits of crea ng be er spaces – crea ng built environments that teach.

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BRIEF HISTORY OF MAURITIUS

Several events have shaped the socio-cultural and built landscape of Mauri us as it is today. Un l the 16th century, Mauri us was an uninhabited island, although the Arabs, who named the island Dina Arabi, used it as a stop to replenish their supplies and repair their ships. In 1598, a Dutch expedi on led by Wynrandt van Warwyck landed on the Island and named it Mauri us a er the Dutch Prince Maurits van Nassau. In 1638 they established se lement in the area that would be known as Port Louis, the current capital, and used the island as a stopover and freely used the ebony trees which was found profusely all over the island. The Dutch introduced sugarcane from Indonesia and imported slaves from Madagascar for the development of ebony trade. It is also the Dutch presence on the sland that largely contributed to the ex nc on of the dodo, a flightless bird only found in Mauri us. The first colonisa on a empt ended badly, and a er a second a empt in 1652, the Dutch permanently abandoned the island in 1710. In 1715, the French took possession of the island and renamed it Isle de France. It was not, however, un l 1735, with the arrival of French governor MahĂŠ de Labourdonnais, that proper development started. Under the administra on of the French East Indian Company, the island developed significantly, especially in terms of agriculture and in the expansion of se lements. During the governorship of Labourdonnais, several government buildings were built - those s ll standing today are considered as the epitome of Mauri an mber-and-stone colonial architecture and are some mes used for a return towards more vernacular inspira ons. Port Louis was transformed into a well defended naval base and a state-of-the naval workshop. Several other infrastructure such as theatre, hospital, market and aquaduct were built. Slavery was also an important aspect of colonisa on, with large numbers of slaves from Mozambique working on sugar, indigo, co on and tobacco planta ons. During this me, Mauri us was used as a major naval and military base for French campaigns against the Bri sh in India, and both the French Navy and French corsairs plundered English merchant ships in the Indian Ocean. Owing to the strategic loca on of Mauri us, the conflict between the French and English escalated (also as part of the Napoleonic Wars) un l the Ba le of Grand Port in 1810. Although the ba le was a French victory (only French naval victory in the Napoleonic Wars) the English later conquered the island in December, and the English possession was confirmed in 1814 by the Treaty of Paris. During the Bri sh rule, French ins tu ons including the Napoleonic Code of Law were maintained, and the French language was s ll used more widely than English. This period saw the increased interac ons with Arab and Chinese traders, who represent a small percentage of the popula on today. Tropical Sustainable Living

The aboli on of slavery in 1835 was a significant event in the history of Mauri us. During that colonial period, the larger propor on of inhabitants in Mauri us were slaves. With the aboli on, the Franco-Mauri an elite, who owned most of the agriculatural lands, had to find alterna ve sources of manpower. This was presented in the form of indentured labourers from India. Large numbers migrated from India to provide the much-needed labour that was formerly met by slaves. However, the living and working condi on of the Indian labourers were very poor and considered by many as hardly be er than slavery itself - they usually lived in precarious dwellings on the estate and o en struggled for respect. By the twen eth century, the Indo-Mauri an popula on had exceeded the creole popula on (former slaves) and had significantly the reshaped the cultural, economic and poli cal physiognomiy of the island. In the 1860s, a violent outbreak of Malaria wiped over 10% of the popula on. Many people, especially the Franco-Mauri ans, moved to the upper plateaus to avoid the disease. This strenghened the social segrega on that existed between the land owners and working class- while the rich were building large comfortable colonial houses in upper towns, the workers s ll dwelled in decrepit condi ons. The type of house people lived in was therefore seen as an indicator of social status. The tropical cyclone Carol in 1960 was another event that would significantly shape the landscape of the island. The cyclone is considered to be one of the most devasta ng natural catastrophe witnessed in Mauri us, leaving over 300000 people homeless. The devasta on saw the need for building houses to resist cyclones - concrete was the obvious solu on. Combined with the idea of the house as an indicator of social status, having a house made of concrete was an ul mate goal for any family from the lower strata of the social divisions. Today, the large number of concrete houses reflect the social condi ons that have started several decades previously. A concrete house is s ll seen as a special achievement, especially among the poorer por ons of the popula on. Very o en, building a house can take several years and happen in several stages, and striving towards building in concrete has been so overwhelming that tradi onal colonial knowledge of building in mber and stone has been lost - carpenters who are able to erect an en re house in mber are a rare treat nowadays. Republic of Mauri us. “History”. 2013. h p://www.gov.mu/English/ExploreMauri us/Pages/History.aspx Ministry of Health and Quality of Life. “Malaria in Mauri us”. 2008. h p://health.gov.mu/English/Documents/Bulle ns/mal-history.pdf Meteo Mauri us. “Severe Tropical Cyclone History of Mauri us”. 2013 h p://www.meteomauri us.com/cyclones-history.html 7

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MOTIVATIONS

WHY ALL THESE ARE AN ISSUE Although building in concrete is a symbol of social achievement and is structurally appropriate to resist cyclones, concrete is otherwise not appropriate because: The climate of Mauri us is warm and humid. Temperatures are not extreme neither in summer or in winter but the high year-round levels of humidity are the major causes of discomfort - in the summer the high levels of humidity prevent evapora on from the skin, crea ng a ‘suﬀoca ng’ environment, while in winter, the increased heat capacity (ability to store thermal energy) of high humidity air is capable of storing more of the coolth and therefore make the air feel much colder. The day me and night me temperatures do not significantly vary either, and this has a direct impact on the concrete, especially during the summer - Concrete has a high thermal mass, which means that it has the ability to store heat. This is useful in the summer as a mass of concrete can absorb heat, thus allowing surrounding areas to feel cooler. This strategy is successful if the concrete is allowed to cool at night so that it can absorb more heat the following day. This process is called a night purge, and relies on a significant drop of temperature at night. In Mauri us, the temperature does not significantly drop at night, which means that the built-up heat does not have me to purge. The following day, the concrete is unable to absorb more heat and simply dissipates thermal energy, adding to the discomfort. WHAT HAS CHANGED RECENTLY Un l recently, the sugarcane introduced by the Dutch in the 17th century was the primary na onal source of revenue. Mauri us had a guaranteed price and quota for the export of sugar to the European Community (Conven on of Lomé.) Recetly this agreement has ended and with sugar no longer being a viable source of income, a lot of the agricultural lands have been converted, mainly into residen al blocks, commercial developments and luxurious villas. The Franco-Mauri an families who have been the owners of the sugarcane planta ons are currently the major developers of these projects. Bagasses, which is the fibrous material le over a er the sugar has been extracted, was also used as the primary fuel in electric power plants. The sugar industry had several economic, social and environmental benefits for the country, but that has changed with the end of the Lomé Agreement.

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OPPORTUNITIES

EXISTING CONDITIONS

The conversion of agricultural lands has led to a boom in construc on. The primary construc on method s ll remains concrete regardless of the scale or func on. The reduc on of the sugar industry has also led to the loss of thousands of jobs. The primary source of energy shi ed from bagasse to coal, and with the considerable dwindling income linked to sugar export, the economy had to diversify, mainly into tourism, tex le and services (Finances and ICT). The opportunity here is to use these abundant agricultural lands to restore a level of social, economic and environmental sustainability that was possible with sugarcane. An architecture that tries to address these issues has the poten al to be sustainable not only over its own footprint, but also on the larger context. Using local materials, local knowledge and local context were a good place to start. The ideas is to use the agricultural lands as they have been for the past 300 years, instead of just covering them with hard built infrastructure.

Top to bo om: Sugarcane field in Mauri us Bagasse Luxurious villa built on converted lands 9

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PROPOSAL

For this design thesis, I am proposing to work from first principles and develop ecologically, socialy and economically sustainable architectural, material and technological systems that create comfortable built environments. I intend to achieve this by designing an educa onal ins tu on that will aim at revalua ng the construc on industry in Mauri us. The occupants of that ins tu on will consist of both academic students and technical students engaged in kinaesthe c learning, both learning about building technologies and design. The reason for these 2 dis nct profiles of occupants is that the knowledge gap exists not only between those who design and those who make, but also in the inherent academic and technical exper se in building technology - people do not know how to design and construct for the Mauri an context. The development of new and innova ve technologies will have to be backed by innova ve learning and teaching methods that will be enabled by the built environment. As such the building is also intended to act as a third teacher.

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CONTEXT

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SITE SELECTION

Bain Boeuf, loca on of formerly chosen site

Port Louis, capital city

Ebene, chosen site

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BAIN BOEUF My formerly chosen site was an village in the north of the island called Bain Boeuf. The choice of the site was primarily a ma er of convenience - the plot of land is family owned. However, a er a site analysis and ini al design interven ons, the site was abandoned for several reasons: The site was too small to accommodate the program I was intending to include in the building The area is a completely touris c and residen al area and therefore inapropriate for a school. The area has li le circula on apart from the movement of residents, which makes it insuďŹ&#x192;cient to â&#x20AC;&#x2DC;adver seâ&#x20AC;&#x2122; the new sustainable living and educa on to the Mauri an popula on. Access to public transport in the area is very poor, making it inconvenient for students. A lot of these students, especially those aspiring to the technical side, will not be 18 yet, the legal age for driving. Bain boeuf is located on the northern p of the island, quite far from the more central ci es. Again an inconvenient loca on for such a school.

Map of Bain Boeuf site rela ve to the public beach

Bain Boeuf Site

Bain Boeuf Public Beach

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EBENE

The process of selec ng the site was therefore focused around the demographics of the intended occupiers. The area had to be an area that would be accessible by public transport, and be central enough so that people over a significant radius would see the building. If one of the purpose of the building is to ‘adver se’ itself as a model of what architecture should be in Mauri us, it would make sense that the said building should be in an area with high traffic. The choice was therefore turned to an area called Ebene (french transla on for ebony). Ebene was one of the areas that used to be covered in sugarcane and converted about twelve years ago into commercial and residen al land. One major development project intended for Ebene was to convert the en re area into a ‘cybercity’, a technological hub that would enable the economy of Mauri us to be supported by IT services. The construc on of the cybercity started in 2001 and was marked by the construc on of the ‘Cyber-tower’. Gradually, a supermarket was built, and so was a residen al complex used as an athle c village during the Indian Ocean Island Games in 2003. A er the games, the athle c village was converted into appartments. Today, Ebene is one of the fastest-growing areas in the country - more than 25 new buildings have been built in less than 10 years over less than 1km2. Currently, most of the ac vi es are centred around business ac vi es- a lot of the services that used to be in the capital have been decentralised to Ebene, with most large corpora ons having a major branch (some mes even their new headquarters) moved to Ebene and 3 major architectural firms have moved their offices there. The demographics is rela vely young, and Ebene has been the new ‘fashionable’ place to work for the younger workforce. The increasing presence of several leisure-oriented facili es (hotels, clubs, bars, restaurants) has also helped a ract more younger people to the area. Residen al areas have also been growing around the Cybercity. All these characteris cs make the area appropriate for the proposed school. The high level of traffic allows the school to be ‘adver sed’ efficiently. Public transport is close-by and frequent, and the younger demographics are the ideal target to ins l new changing ideas of sustainable living. Moreover, the rapid growth of the ‘concrete forest’ in the area could benefit from a new construc on paradigm that the proposed school hopes to inspire. In other words, the area represents the perfect condi ons that this thesis wishes to change, and is located in a demographic environment that is possibly the most malleable to enable such a change. The selected site is currently occupied by a car park (highlighted in red). Tropical Sustainable Living

Mauri us Commercial Bank

Cyber Tower 1

Ebene 2003

Nexteracom Tower

Cyber Tower 2

Ebene 2013 17

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CLIMATE

Mauri us lies around 300 kilometres north of the Tropic of Capricorn and has a tropical climate (Koppen climate classifica on Af-Am). This type of climate usually is characterised by hot and humid air during the summer and cooler and drier in the winter months. Like for most tropical areas, cold is not usually a major problem most people are usually comfortable wearing warmer clothes in the winter, and annual hea ng loads for space condi oning are insignificant compared to cooling loads. Diurnal shi is also very low, with only minor drops of temperature during the night. This is something very important to keep in mind because this is the one climate property that has a significant impact on the type of construc on selected. The island is also under the influence of south east trade winds. Since the island is very mountainous, several areas have their own microclimates (especially those directly adjacent to mountains and hills). Ebene lies on a rela vely flat plateau at it will be assumed, for the purpose of this thesis, that south east trade winds are prevalent in the area. Humidity is also another large factor that needs to be taken into considera on. Levels of humidity are fairly high throughout all the year, but peaks during summer. Combined with heat, humidity is the largest contributor of discomfort. Again it is very important to consider this aspect of the climate while making design decisions and developing construc on and technological systems to support the design. The following table summerises the clima c condi ons in Mauri us Month

JAN

FEB

MAR APR

MAY JUN

JUL

AUG

SEP

OCT

NOV DEC

Wind Speed (km/h) Wind Direction (degrees)

12 115

14 110

15 115

13 120

14 120

15 115

15 120

15 115

13 105

11 105

14 120

Mean Max Temperature (Č&#x2014;c) Mean Min Temperature (Č&#x2014;c)

27.9 20.6

28.6 21.4

27.7 20.8

26.7 20.8

24.6 18.6

22.8 16.8

22.5 16.6

22.4 16.4

23 16.4

24.5 17.5

26.7 19.2

27.7 21.2

21.9

18.8

15.7

14.6

13.2

14.9

17.9

16.7

15.7

19.4

Relative Humidity (%) Average Solar Radiation (MJ/m2)

Climate data courtesey of the Meteorological Services in Mauri us Tropical Sustainable Living

ENERGY MODELLING One of the research components of the thesis would have been the tes ng of different models to evaluate the thermal performance of each model through energy simula ons in IES-VE (Integrated Environment Solu on- Virtual Environments). One of the major barriers to using energy modelling was the unavailability of (or rather unaccessibility to) the climate data required to build a weather file specific to Mauri us. The alterna ve was to use a weather for a place that has a similar climate (Koppen Climate Af-Am) and lies on the approximate la tude (~23 degrees south). 2 choices came up: Antananarivo, Madagascar and Darwin, Australia. Although Antananarivo was closer geographically, Darwin happened to be a be er match in terms of climate. However, even Darwin, the closest match, proved to be rela vely an innacurate subs tute. Moreover, the use of unconven onal technologies and materials (eg, the liquid dessiccant, seaweed insula on, hempcrete, all discussed later) resulted in the models being based on too many assump ons, making them extremely innaccurate. The simula ons ended up being very generic and the only realis cally useful informa on was that lightweight construc on (steel frame and mber panels used in the model) was a be er construc on type than heavyweight (concrete) in such a climate - this informa on is nothing groundbreaking and it is a strategy that has been used in most tropical architectural types throughout the world. Energy modelling therefore became at this point a research avenue that would not yield sufficient informa on and was abandoned. It is at this point that the thesis slightly changed direc on a moved away from a more technical-centric approach to a more design-centric approach (educa on, discussed later). In lieu of modelling, these numbers can ‘manually’ be analysed and strategic decisions can be made to address these issues- the table shows that temperature extremes do not sway too far off the comfortable temperature band (18-25). Humidity, however, is consistently above 80%, which is considered very uncomfortable under any temperature condi on. The temperature peaks can be smoothed quite easily by simple interven ons such as the addi on of insula on, but tackling the issue of high rela ve humidity levels will be an important component in the design of the proposed building.

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SURVEY

Part of the research was to conduct a survey to determine how sustainable living is understood in Mauri us, what are the main barriers and mo va ons, and what strategies can be the most eﬀec ve into encouraging sustainability. Although the results of the survey did not start coming back un l halfway through the thesis, most of the assump ons made at the start happened to be quite close to the responses of the surveyees, so that the ini al design decisions were not completely irrelevant. The survey received approval from the University of Melbourne Human Research Ethics on the 13th of September 2013, HREC Number 1340596.2. The survey is an adapta on of a research conducted by Caitlin McGee for the Ins tute of Sustainable Futures, University of Technology, Sydney. The only requirements for par cipants to be eligible for this survey were that they needed to be 18 years or older, and have lived in Mauri us for at least a year, so that they have had the chance to experience the climate both in summer and in winter. 76 ques onnaires were distributed with recipients ranging from 19 to 61 years old. 8 of these 76 respondents have an architectural design background although it is impossible to know whether they have submi ed a ques onnaire since the iden es are decoupled from the responses. The majority of the recipients are in the 20-35 age group. 37 ques onaires were returned and the results compiled. The ques ons were as follows: 1. What do you understand by sustainability/sustainable design? 2. Based on your understanding of sustainability, do you consider yourself sustainable? • Yes 21 (57%) • No 16 (43%) 3. Based on your understanding of sustainability, do you consider that public services in MauriƟus sustainable? • Yes 30 (81%) • No 7 (19%) 4. In winter, what do you consider the main contributor of discomfort? • Temperature • Humidity • Air Pollutants (CO2, pollen, dust, smells, smoke) • Lack of interac on with the external environment (natural light, natural ven la on) Tropical Sustainable Living

17 (46%) 10 (27%) 5 (14%) 5 (14%) 20

5. In summer, what do you consider the main contributor of discomfort? • Temperature • Humidity • Air Pollutants (CO2, pollen, dust, smells, smoke) • Lack of interac on with the external environment (natural light, nat ural ven la on)

18 (47%) 15 (41%) 3 (8%) 1 (3%)

6. How do you feel about sustainable design? (you can Ɵck more than one) • It does not interest me • It is too diﬃcult to achieve • I cannot make a diﬀerence • It is too expensive • It requires too much lifestyle change • It can help me save money • It can improve my lifestyle • It is the right thing to do • It can add value to buildings • It can help preserve resources

20 (54%) 28 (76%) 25 (67%) 10 (27%) 3 (8%)

12 (32%) 30 (81%) 15 (41%) 12 (32%) 30 (81%)

7. What do you consider the biggest barriers so sustainable design in MauriƟus? (you can Ɵck more than one) • Availability of technologies • Lack of exposure 18 (48%) 32 (86%) • Costs • Lack of technical knowledge 30 (81%) 28 (76%) • Lobbying • unwillingness to compromise lifestyle 33 (89%) 25 (66%) 8. Have you/will you do any of the following? (you can Ɵck more than one) • Water efficient taps/showerheads • Thermal insula on in walls/ceilings • Efficient use of aircondi oning system • Environmentally friendly materials • Rainwater collec on • Efficient ligh ng • Solar hot water/electricity • Waste recycling

17 (46%) 7 (19%) 22 (60%) 18 (49%)

0 (0%) 12 (32%) 36 (97%) 34 (92%)

9. What would most encourage you to implement elements of sustainable design? (you can Ɵck more than one) • • •

Savings on bills Added value to the house Improved comfort and environment quality

• •

Desire to do good 19 (51%) 9(24%) Rebates on sustainability related 11 (30%) 5 (14%) products 27 (73%)

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RESULTS INTERPRETATION

The results from these surveys reveal the following: Most people’s view of sustainability were about the preserva on of resources and mi ga on of global warming. From this defini on about half the popula on considered themselves sustainable while most considered the public services not sustainable. Ques ons 4 and 5 showed that the major contributors of discomfort were temperature and humidity, with humidity being a par cular issue in summer. Ques ons 6 and 7 paint quite a pessimis c view of sustainability in Mauri us. Cost seems to be a par cular problem, with lack of exposure and lobbying being the major barriers. Again, resources seem to be the focus of the understanding of many of the respondents in their view of sustainability. It is interes ng to note that people do not usually associate a sustainable building with one having added value, which might be a possible reason why costs has been raised as a major barrier - it would be difficult for the respondents to consider inves ng more money upfront without a foreseeable payback in the future. Ques on 8 shows the different engagement of people with sustainability. Most of the respodents have switched to energy-saving ligh ng (fluorescent I would guess) and many also engage in recycling, although there is no ac ve recycling strategies in Mauri us (separate recycling and landfill collec on). 0% have insula on in their homes, which is not surprising, due to the absence of suppliers altogether in the country. Overall, it seems that people are willing to engage in sustainable ac vi es if they are quite easy to achieve. Responses to ques on 9 have been rela vely low, with most respondents selec ng improved environment condi ons as the main reason to be sustainable. The way these results will affect the design process will be in se ng a series of ‘rules’ to follow: Fairly low-tech so people can engage more easily Be cheap solu ons so as not to ini ally put off people Have a strong focus on material sensi veness, since this seems to be a major element that talked to the respondents. Tropical Sustainable Living

PEDAGOGY The educa onal system in Mauri us is divided into public, private and catholic. Public and catholic schools are usually boys-only and girls-only, while private schools tend to be mixed. There is a no on in Mauri us called the star-school system, where a handful of schools throughout the en re country are considered to produce the elite students. Oddly enough, none of the private schools are part of this ‘star-school’ system. Many catholic and public schools are highly performance-oriented and push students to academic excellence. All of them do it in a slightly diﬀerent way, but one thing remains consistent: all the methods are very tradi onal. Educa on in Mauri us very much follows the factory model - there is a linear progression and the format of teaching revolves around the teacher delivering informa on and students taking the informa on. The layout of the class follows the model of the teacher’s desk at the front, and students si ng at their desk facing the blackboard. I have a ended one of these catholic star schools for eight years, and I know how it feels. The academic performance of the students were o en excellent, but many (not all though) of these schools tend to favour academic achievement at the cost of the personal development of the student. The school I a ended tended to be a li le more progressive - several teachers encouraged students to be more collabora ve learning, but the way the spaces were arranged discouraged such interac ons. Some teachers also started making use of informa on technology as a teaching aid - IT is s ll not a very prominent element of teaching- but again, the facili es at the school did not make such interven ons be as successful as they could be. The analysis of the survey results has demonstrated that one of the major barriers to sustainable living is the lack of knowledge. Revalua ng the educa onal system is therefore probably as important as developing actual design and technical solu ons - proposing innova ve solu ons is only eﬀec ve if people are educated enough, and willing to apply these changes, even if it requires a change in lifestyle.

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RESEARCH

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CASE STUDY - ENERPOS At the moment, there are only 3 zero-energy buildings in tropical climates. The first one ever built is an extremely appropriate case study for this thesis - It is the Enerpos Building in Reunion Island. Enerpos stands for Energie Posi ve (french for po ve energy) and is part of the University of Reunion. Reunion is a small island 250 km south west of Mauri us. It shares a similar colonisa on history as Mauri us, but has remained a French colony and remains today a French department. Reunion has a very similar climate as Mauri us, but since it s ll has an ac ve volcano, it is a lot more mountainous than Mauri us. Enerpos has been completed in 2008 and has a net floor area of 681m2. 246m2 of air condi oned whilWe the rest is naturally ven lated or is fi ed with ceiling fans. The main construc on for Enerpos is s ll concrete. All walls are made up of 18cm of concrete with either mineral wool insula on, or an aerated air gap. Glazing takes up 30% of the wall and the windows have a U-value of 1.4 and a SHGC of 0.10 or 0.15 depending of orienta on. Shadings have been designed to minimise solar heat gain and daylight and 90% of the ligh ng requirement is provided by natural light. A 3 metre strip of na ve plants has been planted around the building to the surrounding air from hea ng up. The building is also fi ed with temperature and humidity sensors controlled by the BMS. Renewable energies in the form of BIPVs are fi ed on the roof and account for all of the energy requirements of the building. The energy breakout is as follows? 46% plug loads 15% air condi oning 14% interior ligh ng 11% ceiling fans 7% exterior ligh ng 7% elevator Annual energy consump on for 2010-2011: 9824 kWh Annual energy genera on for 2010-2011: 17118 kWh

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ENERPOS

Enerpos has been a very strong influence and inspira on throughout the thesis, both in principles and design. The use of the building and its loca on makes it a very interes ng case study. However, this building explores sustainability in a fairly technical aspect, and strives to achieve high performance using technology. For this thesis, sustainability is explored further than just the environmental sustainability but also social and economic sustainability. As such, the thesis in a certain way pushes sustainability further, by addressing aspects such as the sourcing of materials, the crea on of jobs and the poten al crea on of industry and the connec on to the more vernacular. Lenoir, A., Garde, F. “Tropical NZEB - University of La Reunion’s Enerpos” High Performance Buildings. Summer 2012. 27

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TROPICAL ARCHITECTURE

A lot of documenta on already exists regarding guidelines for tropical architecture design, and while many of these rules of thumb are very general and very generic, these guidelines can be extremely useful, especially during preliminary design stages. Some of these guidelines include: The orienta on is an important feature to maximise the eďŹ&#x20AC;ects of the sun and the wind. The building needs to be oriented to catch the breezes and to minimise wall areas towards the west.

In hot humid climates, it is important to get rid of the humidity. The most eďŹ&#x20AC;ec ve way of achieving this passively is through natural ven la on. Orienta on and room layout are important to allow the air to cross through and carry the humidity and improve evapora on. External design elements such as porches and bu resses can be used to direct breezes inside. Natural ven la on can be driven by the wind, but also by the convec onal movement of rising hot air. This type of ven la on is called stack ven la on and will be discussed later. Ven la on can also be helped using fans, and although this is no longer fully passive, can dras cally improve air movement in areas where natural breezes so not reach.

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VENTILATION, SHADING AND INSULATION

Besides from heat transfer through the air, heat can enter a building through solar radia on through the windows. While windows allow natural light and fresh air in, they also heavily contribute to heat gain and it is important to shade them. Since the sun behaves diďŹ&#x20AC;erently from diďŹ&#x20AC;erent direc ons, the shading treatment on every facade needs to be diďŹ&#x20AC;erent. Eastern and western facades need to have ver cal shades to deal with the lower suns that shine almost horizontally. Northern facades (in the southern hemisphere) need to have horizontal shadings to prevent sun penetra on from a higher angle. The length and height of the shadings can be cleverly designed so as to block the higher sun in the summer and allow the lower winter sun in during the colder periods. Local shadings in the form of blinds and curtains can also be used to selec vely block or allow solar radia on.

There is a certain misconcep on in Mauri us that insula on is only for cold weathers. Insula on is very important for hot climates as well, especially inside the roof. A combina on of ven la on and insula on in the roof can prevent heat from accumula ng inside the roof space and transferring through the ceiling. Similarly, insula ng walls will prevent solar radia on from transferring through the material. Insula on materials can take the form of an air filled material that prevent heat transfer by conduc on, or as a refle ve foil that blocks thermal transfer by reflec ng electromagne c radia on.

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PLANTS

Plants can be used for several purposes. Plants on the outside of buildings can act as shades to prevent solar radia on from hi ng the building envelope. Plants can be used on the surface of the envelope itself, in the form of green walls and green rooves. Besides ac ng as a shade and adding a layer of insula on, plants can also cool buildings be evapo-transpira on- by evapora ng and transpiring water, the plants create a cooling eďŹ&#x20AC;ect around the air and directly onto the surface they sit on. The cooling eďŹ&#x20AC;ect of green rooves is probably aďŹ&#x20AC;ected more by the evapotranspira on than the actual R-value of the plant + earth. Some plants, such as vines, can be cleverly used on trellisses to act as seasonal shades - in the summer the leaves would grow and block the sun, and in the winter, the vines would shed their leaves and allow the sun in to heat up the internal spaces. Plants can also be used to direct breezes strategically towards openigs of the buildings to improve natural ven la on. Furthermore, by moving past trees, the breezes will be cooled down before entering the building. Plants used internally can be used to improve the interior air quality by filtering dust par cles and absorbing chemicals and pollutants. However, in tropical climates, where humidity is a problem, plants transpiring internally might not adequate, and the proper types of plants need to be inves gated beforehand.

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Lightweight Building Materials The en re idea of using lightweight materials is that they have low heat-storing proper es and therefore do not radiate heat internally. Tradi onal building materials such as wood, grass, palm or bamboo are cheaper than, and feel cooler than masonry. The reason is that diurnal shi s are very low in warm tropical climates. Masonry materials such as brick and concrete have high thermal mass, which allows them to store thermal energy. With low diurnal shi s, the thermal mass does not have the opportunity to purge that heat at night, resul ng in the material to radiate heat back internally the following day. Also, condensa on can happen very easily when there is a slight temperature diďŹ&#x20AC;erence between the air and the surface it is in contact with, since high himidity air is very near dew points. There is no me lag between temperature fluctua ons between the lightweight materials and the air, thus reducing the occurrence of condensa on. Lightweight materials do not store thermal energy and therefore do not radiate the heat back internally. Lightweight materials are o en natural, plant based, and are therefore prone to insect a acks and weather damage, and must therefore be used carefully. Steel frame is also a form a ligh rame construc on, but is more durable than mber/plant based lightweight frames. Lightweight frames can also be used together with masonry for structural or resistance reasons. Masonry has also been used tradi onally in hot tropical climates. Earth buildings have been built tradi onally and have been known to last very long. While compressed earth blocks are s ll considered masonry, they will s ll feel cooler because they store less thermal energy and react quicker to temperature changes. This also means that condensa on problems will be less prevalent.

Bamboo and earth school

Earthblock building

Wood house on earthbag founda on

Stouter, P. â&#x20AC;&#x153;Shaping Buildings for the Humid Tropics: Cultures, Climate, Materialsâ&#x20AC;?. November 2008 31

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LIGHTWEIGHT BUILDING MATERIALS

SYSTEMS

HVAC systems are usually significant consumers of energy in a building, and are therefore primary component that can be addressed in terms of energy reduc on. This can be achieved in several ways: by either using more eﬃcient HVAC systems (eg incorpora ng heat recovery) or by improving the building fabric and reducing HVAC use. Using passive systems as much as possible can also significantly reduce HVAC use. Usual passive strategies include include thermal mass, solar hea ng and cooling, natural ven la on, shading. Not all of these strategies are always appropriate, and they need to be carefully selected and smartly used together so that the eﬀect of one can enable the other to perform at its op mum performance. Mauri us is a fairly low tech country. Even though it is fast developing, latest building technologies such as cogen or trigen do not see everyday applica ons. Even solar panels are not very common. The survey has shown that lack of technical knowledge is a major barrier in Mauri us. Educa ng people about these technologies is an op on, but realis cally, op ng for a low-tech solu on has more poten al of succesding. The reason for low tech are: •

•

High tech are usually a bigger ini al capital costs. Many Mauri ans do not yet possess the vision to see how ini al capital costs can have long term financial benefits. This is demonstrated by the rela vely low level of response to the survey responses “savings on bills” and high level of response to “rebates to sustainability products”, bith from ques on 9. High tech technologies are also usually high maintenance and have specific opera onal requirements. Even in developed countries like Australia, where people are generally more technology-aware, these things some mes go wrong (eg janitor’s encounter with Pixel Building’s vacuum toilet). The Mauri an “slackness” concerning these more stringent maintenance and opera onal requirements might just result in these technologies not working properly. this may sound prejudicial but past experience with Mauri an services has made me come to this conclusion. Latest technologies will usually have to be imported from overseeas. Part of the focus for the thesis is the local sourcing of technologies and materials. Having to import not only the equipment but also possibly the exper se to run the systems goes somehow against the direc on of this project.

These condi ons are only relevant for the present condi ons. Mauri an society is changing, and it is very possible that these condi ons will no longer apply in the coming years.

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One strategy to look at eﬃcient low technologies was look at tradi onal technologies that have been used for centuries to create comfortable condi ons. The sun is a virtually limitless source of energy. It might be counter intui ve using the sun for cooling, but harnessed properly, the sun can drive cooling mechanisms. One of these mechanisms is the thermal chimney. The thermal chimney relies on the property that air expands when heated up. The expanded air is less dense and will rise above the cooler air. This is called convec on. The basic thermal chimney drives warm air outside by hea ng the top of a chimney, crea ng a convec onal current that will suck air from the inside.

The top of the chimney is painted black to absort the maximum amount of radia on. When the air at the top of the chimney rises and leaves the chimney, it sucks up the air from the inside of the building. A vent located somewhere else will allow fresh cool air inside the buiding. When thermal mass is included inside the system, the chimney will keep extrac ng air even a er the sun has set. This system creates a constant circula on/cooling throughout the building. Some mes an extrac on fan at the top of the chimney is used to help fllush out the air. Gut, P. 1993. “Climate Responsive Design: Appropriate Building Construc on in Tropical and Subtropical Regions”. SKAT: Switzerland 33

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THERMAL CHIMNEY

THERMAL CHIMNEYS VARIATIONS

There exist several varia ons of the thermlal chimney. One of them is having an en re wall sec on ac ng as the â&#x20AC;&#x2DC;chimneyâ&#x20AC;&#x2122;. The wall is made up of a cavity that heats up the air it contains and allows the hot air to rise. The rising air then sucks the indoor air from vents in the wall, instead of through the ceiling. This type of thermal chimney is also a varia on of the trombe wall, a system that heats air inside a solar and redistributes it inside an internal space for hea ng.

The images above show thermal mass between the wall cavity and the internal space. Some mes, instead of thermal mass, a highly insulated material is used to prevent heat conduc on from the cavity when the chimney is configured for cooling.

60L Tropical Sustainable Living

CH2

NAB Docklands 34

The idea behind geothermal energy is to use the temperature of the ground to passively condi on a hea ng/ cooling medium. Usually, water or air is pumped through underground burried pipes and allowed to be condi oned passively. The advantage of geothermal is that the ground temperature remains rela vely constant during the year, so can be used all year round.

Geothermal can also be used in conjunc on with a thermal chimney. The air extracted from the chimney pulls fresh air through an earth tube that is allowed to be condi oned by the ground. For this project, the problem of this system is that for this to work, the building needs to be sealed for the pressure diďŹ&#x20AC;erecnces to drive that air movement. When naturally ven la ng a building, sealing is not possible. Moreover, the ground temperature in Mauri us is 24.3 degrees celcius, and the (small) amount of geothermal cooling might not be worth the installa on of earth tubes. For this reason, geothermal will not be used for this project despite its interes ng poten als. Autodesk Sustainability Workshop. Trombe Wall and A ached Space. 2011. h p://sustainabilityworkshop.autodesk.com/buildings/trombe-wall-and-a ached-sunspace Top-Alterna ve-Energy-Sources. What is A Geothermal Hea ng System? 2012. h p://www.top-alterna ve-energy-sources.com/geothermal-hea ng-system.html 35

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GEOTHERMAL

STACK VENTILATION

Stack ven la on is not completely dissimilar to the principle of the thermal chimney. It also relies on convec on but not sun-driven convec on. Stack ven la on happens when the internal heat-genera ng ac vi es inside a building heats up the air. The air then heats, rises and accumulates close to the ceiling. If this warm air is allowed to rise further and evacuated further up, then space then passively refreshes the air. This is stack ven la on. Certain space arrangements such as atria can enable or facilitate stack ven la on.

Stack ven la on can work beau fully well together with natural ven la on and thermal chimneys. Natural cross breezes can push warm air from occupied spaces into the atria, the air will naturally rise and be evacuated up, by either being blown away of by being sucked out by a thermal chimney (or a space doing the same thing.) The use of stack eďŹ&#x20AC;ect in architecture is heavily inspired by how termites manage to condi on their mounds incredibly well using stack ven la on.

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Heat can some mes be unbearable in Mauri us, especially during the peak of summer. However, the high temperature itself is not the only culprit. The average high in February is 28 degrees celcius, only a few degrees oďŹ&#x20AC; the 18-25 comfortable temperature band. The other factor is humidity. The natural mechanism that the human body uses to regulate its temperature is through swea ng. When it gets too hot, the body transpires water through the pores, and when this water evaporates, it carries away the heat with it. This is the same way plants keep green rooves cool. In humid tropical climates, the air is already saturated with water so much so that evapora on cannot occur. Warm sweat accumulates on the skin and people end up extremely uncomfortable. The reason why ven la on is a strategy widely applied in tropical climates is because the movement of air actually encourages evapora on - the air brought in from the outside is not necessarily much cooler, but the evapora on that it enables creates a cooling eďŹ&#x20AC;ect directly on the skin of the occupants. One strategy to improve the comfort inside the building is therefore to take care of the humidity. A material that removes humidity from the air (or any medium) is called a desiccant. Building systems making use of dessicants already exist. They usually take the form of a desiccant wheel. Desiccant wheels are usually made of salt, and humid air is passed through a honeycomb structure inside the wheel. As the air passes, the salt absorbs any humidity from it. The wheel then needs to be regenerated by heat. Regenera on refers to the process of removing the water from the desiccant by applying heat to it.

The problems with desiccant wheels are that they tend to be extremely large and expensive. Moreover, the constant rehea ng of the salt during the regenera on process creates a fair amount of material expansion and contrac on. This mechanical fa gue o en results in the salt breaking, and the wheels needing to be replaced quite o en. The large size, high price and high maintenance costs result in desiccant wheels not usually being used unless very precise humidity levels are required.

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DESICCANT

LIQUID DESICCANT

A fairly new technology called liquid desiccant has recently started to be used. A liquid desiccant is basically a desiccant salt dissolved in water. The salts used in liquid desiccants have such a strong aﬃnity with water that even in a solu on, they s ll manage to a ract water. The strongest salts have a water a rac on factor of 25, which means that they can absorb as much as 25 mes their own mass of water. A 1:1 concentra on of desiccant solu on could therefore poten ally s ll absorb 24 mes its own mass.

regenera on absorp on sun radia on

water diﬀusion

salt diﬀusion

A simple model developed by Advan x showed demonstrated how a liquid desiccant can poten ally be used. 2 glasses full of dessicant are placed inside and outside and connected. When the sun shines on the outside glass, water evaporates from the solu on, making it more concentrated. Through the diﬀusion mechanism, salts move from the outside in, and water inside out to balance the concentra on. The higher concentra on inside will a ract more water from the indoor air, while the sun will keep regenera ng the outside desiccant. This combina on of absorp on, diﬀusion and evapora on serves as a pump to carry water from the inside air, through the desiccant and out the outside air.

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While this process can physically work, the diﬀusion process is very slow, especially if the regenera on and absorp on components are quite far apart. Instead, the dissolved desiccant can mechanically be pumped to be regenerated somewhere else.

1. Humid air is drawn into the condi oner 2. The air is blown over the desiccant to be dried and cleaned 3. Clean dry air is released into the building 4. ‘Used’ desiccant is pumped to the regenerator 5. Outdoor air enters the regenerator and heat is applied to the desiccant to boost evapora on 6. Moisture is blown out as vapour. 39

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LIQUID DESICCANT

The liquid desiccant has several major advantages over the regular solid desiccant wheels and tradi onal air condi oning systems: • Since the desiccant is a liquid, it is not aﬀected in any way by mechanical fa gue during the constant absorp on and regenera on processes. Liquid desiccants therefore can poten ally last much longer. • The nature of liquids mean that it is easily to pump them around. The ability to pump the desiccant through pipes makes it much more versa le as it can be carried where needed. • Tradi onal AC systems use large amounts of energy to compress the air in order to dehydrate it. Very o en, these AC also have to overcool the air to dewpoint, and then readd heat to make it comfortable. This is an ineﬃcient use of energy, and o en the reason why many crowded area such as air planes and theatres, which have high latent load requirements, are too cold. For the liquid desiccant, the only energy required is for the distribu on pumps and the regenera on heat - that can be obtained from the sun, or reject heat from other processes. • Blowing the air above a liquid cleans the air. The desiccant will trap dust par cles and pollutants, and the highly saline nature of the solu on will kill any germ and living contaminant. • Tradi onal AC have the tendency to breed mould and legionella because of the accumula on of water inside the condenser. When the air is blown over the mould and other organic growth, it is actually being contaminated before being distributed inside. Liquid desiccants do not have these problems. The moisture in the air is directly absorbed into the desiccant instead of dripping over condenser fins. Moreover, all components in contact with the desiccant have no risk of developing mould or legionella since every living organism will be killed by the saline solu on. While the working principle behind the liquid desiccant is quite simple, it is a fairly new technology that is not yet widely used. While this sounds to go against the local low-tech philosophy of this thesis, an argument could be made for its implementa on in Mauri us: The current salt used in commercial liquid desiccant systems is Lithium Chloride. Other salts such as magnesium chloride and calcium chloride can also be used. MgCl2 and CaCl2 are cons tuents of seawater bi ern, a waste byproduct produced in desalina on plants. At the moment, there are 19 desal plants in opera on in Mauri us, with several expressions of interest to expand the use of desal. The brine produced at these plants is currently diluted before being rejected. Filtering and concentra ng this brine could poten ally lead to the local produc on of a calcium chloride based liquid desiccant. As a reference, 1m3 of CaCl2 liquid desiccant can be obtained from 240m3 of brine, and 600m3 of brine can be obtained from 1000m3 of seawater. If the technology becomes implemented, the local sourcing of the the desiccant is a possible prospect.

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Most exis ng liquid desiccant systems take the form of an air handling unit not dissimilar to regular HVAC AHU’s. AHUs are not very a rac ve and are usually hidden on roodtops or stashed inside a cuploard. All processes happen without any no on of what is actually happening.

Liquid desiccant units such as this one (Advan x DX3400) are usually hidden inside plant rooms or roof tops.

The University of Maryland has developed a sustainable house called the Leaf House, where a close collabora on between architecture and engineering resulted in intricately linked systems and components. One of the design interven on was to create a liquid desiccant wall that displayed how air crosses the desiccant and is distributed to the rest of the house. A conven onally hidden building system is celebrated and used as a design feature instead of being concealed.

Advan x Systems. “Innova ve Liquid Desiccant Air Condi oning”. 2013 h p://www.advan xsystems.com/how_it_works.php Davies, P., Knowles,P. 2006. Seawater bi erns as a source of liquid desiccant for use in solar-cooled greenhouses. in “Desalina on”. Vol 196, pp266-279. 41

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LIQUID DESICCANT AND DESIGN

SOLAR PANELS

Solar panels are a fairly standard feature of sustainable buildings. The solar data from the Meteorological Services in Mauri us, and the case study from Reunion Island have shown that solar power is a possible prospect for Mauri us. However, prices of PV’s are s ll quite high (cos ng up to another 10% of the construc on cost). For the same reasons men oned previously, high ini al capital investments may discourage people to opt fot this op on. However, an increasing number of buildings is adop ng solar technology, and banks are star ng to provide special loans towards the purchase and installa on of PVs. Society is star ng to change, and if addi onal rebates or subsidies are available, or if the price of energy (which is rela vely low at the moment) rises, then solar technology might present real poten al. For the purpose of this thesis project, solar panels will not be used, but the research recognises the (near) future poten al of solar energy and the proposed building will be designed in a way that would allow retrofit should PVs become economically (more) viable in the future Sustainable Mauri us. ‘Solar Panel Costs in Mauri us’ 2011. h p://sustainablemauri us.blogspot.com.au/2011/10/solar-panel-cost-in-mauri us.html IPS. ‘MAURITIUS: Renewable Energy gets a boost’. 2011. h p://www.ipsnews.net/2011/01/mauri us-renewable-energy-gets-a-boost/ Tropical Sustainable Living

Greeen rooves and walls can add several desirable features to a building. One of the most important one is their ability to thermally cool the building fabric in several ways - the leaves act as a solar barrier to prevent the sun radia on from directly hi ng the wall/roof; the soil acts as a thermal barrier by actually having an R-value; and evapotranspira on from the leaves have an addi onal cooling eďŹ&#x20AC;ect on the fabric. Besides improving the thermal performance, greenery has physiological benefits on humans and can contribute to preven ng the sick building syndrome (reconnec on to nature), filter and purify the air, can also improve the biodiversity of the region by providing natural habitats for local species and can improve the hydrology of an area by reducing excess stormwater runoďŹ&#x20AC;. While the benefits of green rooves and walls are quite obvious, one of the mechanisms used by plants can play against indoor comfort in a tropical climate - the mechanism in ques on is evapotranspira on. As men oned previously humidity is a problem in Mauri us, and transpiring plants will only add to the problem. Indoor plants will add to the cooling, but may hinder any a empt to reduce humidity. The balance of temperature and humidity is hard to exactly determine and it might well be possible that the plants can reduce the temperature suďŹ&#x192;ciently so that high humidity is no longer a problem. There is, however, a type of plant that does not transpire so much, while s ll having the benefits of other plants. These plants are called air plants - these develop roots mainly for support and get all their water by absorbing moisture from the air through the leaves. Not only will these plants not release moisture into the air, but they can also reduce the humidity level. 2 plant species considered air plants are the Tillandsia and Epiphyte. None of these plants are na ve to Mauri us, but can withstand a wide spectrum of weather condi ons, making their growth possible in the Mauri an climate.

Epiphyte Bromeliad 43

Tillandsia Fasciculata Tropical Sustainable Living

GREEN ROOVES AND WALLS

The major factors aﬀec ng the choice of materials for this proposed building are (as much as possible):

MATERIALS

• • • •

Sustainable Lightweight Locally sourced Can be constructed using local knowledge and skills

The label ‘sustainable’ is very wide and can be interpreted in a variety of ways. The way sustainability is interpreted in this thesis emcompasses the following elements: • • • •

The materials need to be environmentally friendly The materials need to be renewable The materials need to have low embodied energy The materials need to be socially and economically sustainable - this means that the sourcing and use of these materials can enable or improve social and economic ac vi es. By these ac vi es I mean boos ng new industries and crea ng jobs.

Besides its poor performance in the Mauri an climate, there are other reasons why concrete is not appropriate from a sustainability point of view. • • • •

Concrete has a very high embodied energy Concrete has a very high carbon footprint Concrete is not usually recycled (at least not in Mauri us) which means that all the material and energy put into the material are lost at the end of the material life. Concrete uses non-renewable raw materials - in Mauri us, coral sand used to be used as part of the aggregate mix, and the extrac on of coral sand from coastal regions has badly aﬀected natural ecosystems. Ever since, coral sand has been replaced by rock sand. Basalt, which is the main rock the island is made up of, is a be er choice for sand, but is s ll a finite material source - eventually if concrete construc on con nues, basalt will get more scarce, without any means to regenerate it.

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Bamboo is o en considered as the sustainability hero, for reasons including widespread availability, the low level of exper se required to construct with it, the readily useable form it is obtained, and the rela vely high durability and strength. Bamboo has o en been seen as a ‘poor-man’s’ mber, and used primarily in developing countries. However, a niche as a premium material is star ng to grow in the upperclass market. Generally bamboo as an innova ve building material is interes ng because: • •

• • •

It is extremely sustainable it grows extremely fast - some larger species (those that can grow to 30 metres) can grow as much as 1m a day, and maturity is usually reached in six years. This means that a fully grown 30metre bamboo trunk can be used for construc on a er only six years. For comparison, so woods like pine and cedar can take up to 30 years to reach maturity, while hardwoods such as oak or mahogany can more than 100 years. Bamboo has strength and durability comparable to that of hardwoods. Bamboo is rhizomic and the plant will keep growing even a er it is cut. Depending ont he age at which it is harvested, bamboo can be used for a range of diﬀerent purposes (food, tex le, paper, construc on)

In the context of Mauri us. bamboo can be suitable because: • Bamboo grows very well in humid tropical climates • The low tech nature of bamboo construc on makes it suitable for the low-tech iden ty that this research project is trying to achieve. • Looking at a wider sustainable context, growing bamboo in Mauri us could have several social and economic benefits - at the moment sugarcane fields are being phased out and the major conversion is into residen al and commercial construc on lands. One of the largest cane field owners in Mauri us is the ENL Group - at the moment they own 4900 hectares of cane fields, and every hectare generates ~ $5100 per year. Sugar will soon no longer be a viable economic source, and ENL is willing to replace cane fields with anything than can bring them a return of equal to or more than what sugarcane is currently bringing. Given the fast-growing nature of bamboo, it might be possible that such a number be reached. • If bamboo is planted in Mauri us, it will trigger a new economic ac vity centred around the growing, harves ng, processing and even possibly the export of bamboo. Moreover, it will be ecologically be er to retain agricultural lands and convert from sugarcane to bamboo, instead of having more built areas (retain ecosystems, reduce urban heat island eﬀet). 45

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BAMBOO

Bamboo concstruc on comes in diďŹ&#x20AC;erent forms. Tradi onally, the bamboo is simply cut and used as logs and ed together using lashings, or locked together using the flexible proper es of bamboo. These methods of bamboo construc on are the lowest-tech and require the least amount of energy.

A more modern way of a aching the bamboo pieces together is to use metal connec ons. This method requires more modern equipment such as power tools, but is probably less labour intensive and creates less interes ng design features.

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Bamboo screens are also very common. Usually, thinner pieces of bamboo are either woven or ed together. They do not possess any structural proper es but can provide a certain level of protec on and are usually breatheable.

Bamboo can also take a more mber-like form in forms of laminates. Larger pieces of bamboo are split lengthwise, steamed and fla ened. The fla ened pieces are then laminated together into boards using glue, heat and pressure. These laminates are usually used for flooring, but there is no reason why these canâ&#x20AC;&#x2122;t be used for walls or ceilings. This form of bamboo has more embodied energy because of the processes involved in their conversion. However, larger, flat pieces can be obtained that way, and lamina ng with bamboo is s ll more sustainable and probably cheaper than lamina ng with solid imber.

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BAMBOO

Shigeru Ban is a Japanese architect who is famous for his innova ve work in paper, mber and bamboo. He usually uses a shell grid design with laminated pieces of bamboo to create interes ng spaces.

SHIGERU BAN

Bamboo Pavilion

Pompidou Centre, Metz ( mber)

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Nine Bridges Golf Resort

Cardboard Church (cardboard)

Hempcrete looks very similar to concrete. However the components and proper es are very diﬀerent - hempcrete is made up of a mixture of hemp hurds and lime. Although considered masonry, hempcrete is about 8 mes less dense than concrete and has 1/20 of its compressive strength. As such, it cannot serve as a structural component and must be used within a structural frame. Hempcrete has many interes ng sustainability-related proper es: • Hemp is a plant, and can therefore be considered as a renewable material. Although lime is usually obtained from the mining of limestone, hempcrete is far more sustainable than concrete. • Hempcrete has very good thermal and acous c insula on proper es. • Because of the lime in the mixture, hempcrete is fire resistant. • Because it is plant based, hempcrete is considered carbon-nega ve. • The hemp will keep sequestra ng carbon even in the hempcrete form. 1m3 of hempcrete can absorb and lock up to 165kg of carbon over its lifespan (several decades) • Hempcrete is a breathable material that regulates the moisture of indoor environments. • It can be cast in-situ or precast in factories.

Once again, hemp is not industrially grown in Mauri us but the incredible proper es of hempcrete might encourage its use in Mauri us and eventually the growing of hemp. Moreover, hempcrete is visually very similar to concrete, so the design of hempcrete buildings can have the same aesthe cs as their concrete counterparts, and can therefore be more easily accepted in Mauri us. Envirotecture. “Hempcrete - a whole (not so) new low energy material.” 2012. h p://www.envirotecture.com.au/hempcrete-a-whole-not-so-new-low-energy-material

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HEMPCRETE

SEAWEED

Mauri us has 330 kilometres of coastline, and seaweed o en accumulates on the shores on the island. A large por on of the coastline is made up of beaches, and the seaweed, which is an undesirable element on the beach, is removed and discarded. Un l quite recently, there has never been any thought about how this seaweed could be used in a usefull manner. A researcher from the University of Mauri us, Dr. Dhanjay Jhurry, has conducted extensive research regarding the poten al use of seaweed. Some of the poten al uses of seaweeds and algae found in Mauri us that his research has iden fied are: • Addi ves in the food inductry (gelling, thickening, stabilising agents) • Pes cides • Flame retardants • Himidity control • Cosme cs • Use in pharmaceu cal and biomedical industries • Biopolymers All the above products/niches are high value-added, meaning that small quan es of the la er can yield high economic returns. While seaweeds accumulate in fairly large quan es along the coast, the natural abundance is not so great as to realis cally use them on a large scale (such as for construc on). The more intensive land based cul va on is an aspect that the researchers from the University of Mauri us is currently looking into.

The interest in seaweed as a construc on materials lies in the physical proper es that result from the high salt content. Seaweed, once dried and compacted have the following proper es: It has good insula on proper es (as good as mineral wool) It is fire resistant It does not rot It repels insects and small pests. Tropical Sustainable Living

A type of seaweed called Neptune balls forms naturally into balls. A German company called NeptuTherm has successfully managed to convert these seaweed balls into thermal insula on.

SEAWEED

A holiday house in Denmark pushed the use of seaweed even further by making it the primary building material for walls and roof. In addi on to the fantas c proper es of seaweed, notably its very good thermal insula on proper es , its ability to regenerate itself naturally every year and having a lifespan of around 150 years, the use of seaweed as a cladding material on this Danish house had strong vernacular overtones. Should local seaweed in Mauri us become an economically viable construc on material, it could be used as insula ng material and as insect control, which is always a problem in warm climates. Jhurry, D. “Towards a Bio-based Industry in Mauri us.” University of Mauri us. Grozdanic, L. 2013. “Seaweed-clad House in Denmark Combines Natural Materials with 21st Cetury Building Techniques”. Inhabitat. http://inhabitat.com/seaweed-clad-house-in-denmark-combines-traditional-materials-with-21st-century-buildingtechniques/

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TIMBER

Prior to European se lement in the 16th century, Mauri us was covered by a dense rainforest, mainly of the precious ebony tree. Today, only 2% of the indigenous rainforest remains, and is protected in The Black River Gorges Na onal Park. Several foreign species have been introduced and today both evergreen and deciduous trees are known to grow, but not for large-scale use. Most of the mber used in Mauri us is imported, mainly from South East Asia. Timber as a construc on material is not very widely used, and finds its use mainly internally as doors, windows, staircases, ballustrades, flooring, mouldings, skir ngs and furniture. Many hotels, in an a empt to ‘sell’ the vernacular Mauri an culture use more mber in their architecture, but the bulk of the construc on material is not usually mber. Timber varie es most widely used are pine, sapele and mahogany. Even the use of solid mber is increasingly being replaced by composites and laminates, that are mostly manufactured locally. One of the most widely occurring species of trees in Mauri us is the casuarina, an evergreen trees that is known as `filao’ by the locals. The casuarina is fairly abundant along the coasts and grows fairly straight. Because of its interlocking grains it is known to be diﬃcult to work with, but that same feature also makes it extremely strong. The trunk of the casuarina has o en been used as columns or beams, and I have had personal experience with casuarina floorboards.

Although the casuarina is not a na ve species to Mauri us, it is always associated with the beaches, which is a very important component of the Mauri an culture. Using casuarina in the construc on can be a way of bringing back the vernacular into the architectural culture, which tends to be lost.

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All in all, the interest in the local sourcing of materials and the focus on plant based materials ( mber, bamboo, hemp, algae) does not only have to do with their good environmental performances, but also owing to the economic condi ons in Mauri us - with sugar exports going down, the island is le with thousands of hectares of agricultural lands that need to be converted. If seen from a purely economic point of view, conver ng the lands for commercial or residen al use makes perfect sense (although many of the commercial centres have become fairly empty in the past few years.) Ge ng rid of the greenery will have several impacts on the island. Replacing more greenfield with built areas will only increase the urban heat island effect, will affect the hydrology and the adverse effect of stormwater runoff and all the other nega ve impacts of urban sprawl. The argument is not that construc on should not happen - development needs to be supported by infrastructure. However, if construc on needs to happen, it needs to happen in a strategic way, in a way that allows the land to support the construc on. Mauri us has been ranked as having one of the cleanest airs in the world, and the high coverage of greenery certainly has something to do with it. By allowing part of the land to remain greenfields, the island can retain some of the benefits associated to having large por ons of aggricultural lands. Besides the environmental benefit, remaining green has another benefit - Mauri us is a top tourist des na on and one of the common posi ve feedbacks that tourists provide is the landscape of the country- the mountainous and relief and the sprawling fields. Ge ng rid of the la er will be a terrible loss to the Mauri an heritage, and although it is the sugarcane that is at the crux of this heritage, retaining the agricultural aspect would nonetheless be a be er way of rethinking the landscape of the island.

2nd green revolu on. “Cleanest Air in the World?WHO ranks the Best and Worst Places”. 2011. h p://2ndgreenrevolu on.com/2011/09/27/cleanest-air-in-the-world-who-ranks-the-best-and-worst-places/ 53

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AGRICULTURE AND INDUSTRIES

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DESIGN PROCESS

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INITIAL CONCEPT SKETCHES

Without any no on of scale, performance or services, several conceptual sketches were made during the early stages of research and inves ga ons. Many of these sketches were completely diďŹ&#x20AC;erent from what the final design would be, but they were all part of the design process that started well before ideas were formally put on paper.

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INITIAL PLANNING INTERVENTIONS

The ini al plannings had for purpose to determine the spaces that would be required to sa sfy the brief, and how these spaces would interact with one another to enable the type of human interac on that was intended. It is during the earliest stages of planning that the site at Bain Boeuf was discarded. However, many of the planned spaces have been transferred to the Ebene site, and adapted to the context.

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INTERIM STAGE

Technical Wing Academic Wing Exchange Space Green Areas External Engagement

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GROUND FLOOR PLAN

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FIRST FLOOR PLAN

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FEEDBACK AND CRITICISMS. The feedback received during the interim stage was taken onboard as an addi onal design driver. Some of the most useful pieces of feedback were: • • • • • • • •

The research was extremely thorough The strongest aspects of the presenta on were the par diagrams. Representa on of some of the informa on did not properly convey the ideas behind the design (eg cross ven la on). The spa al syntax did not manage to exactly embody the idea of gradual collabora on between the different facul es and the interac ons between the different academic levels. Materiality and inves gated construc on principles were not celebrated sufficiently in the design besides statements that they were part of it. Design was too separate from context. Vernacular aspect of Mauri an architecture was missing. More design should be undertaken in sec on.

The interim presenta on was held on the 20th of September 2013. Design crit panel consisted of: Dr. Dominique Hes Prof. Philip Goad Dr. Boon Lay Ong Prof. Clare Newton Dr. Ben Cleveland Mrs. Sarah Blackhouse Mr. Richard Leonard

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POST INTERIM DECISIONS Some of the design decisions made a er the interim were: • • • • • • • •

Rework on the spa al syntax to improve narra ve and interac ons. Addi on of more outdoor green space on every level. Moving atrium to more centralised area to obtain increased benefits for internal spaces. Ge ng rid of long dark corridors Using bamboo and mber not only as cladding, but also as structure Expressing the materiality be er Overall form and detailed sec ons changed to be er harness cooling eﬀect of the wind Work be er with the site context

Overall, the post interim design was a significant change from the one presented during the interim. However, many of the strongest core design values were retained and improved: • • • • •

The dual wing separa ng the technical and the academic wings of the school The integra on of green inside and outside The use of lightweight construc on The crea on of communal spaces The celebra on of systems, namely the liquid desiccant and the thermal chimneys.

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SPATIAL SYNTAX

Similar to the previous design, the spa al syntax of the changed design will s ll create spaces of innova on at the intersec on of the two wings. The narra ve of how these interac ons happen is what is the most radically changed: Previously, the interac on happened at a pla orm between the wings and created a double volume circula on/ study area. While the openness created a direct and obvious connec on, the loca on and programme was quite haphazard and awkward, and did not follow a logical progression with the rest of the space. For new design tells the following story: â&#x20AC;&#x153;Students wishing to study in any one of the facul es enter through the same entrance, and are immediately welcomed in a communal area and the atrium, the main central social space, the main place of interac on. As they enter the students are awed and inspired by what they could accomplish in a couple of years, since the atrium also doubles as an exhibi on space. From there, they can choose their preferred pathways, which will lead them to either of the wings. They move to the top of the building so they can have views on what is happening below. The first years are thus protected by being above, and can see and be inspired by what is being done below them by later-year students. The top sec ons of each wing are fairly separated from each other, which allows students to focus on what they learn. As they progress through their respec ve academic careers and gather more knowledge, they move down the diďŹ&#x20AC;erent levels where the spaces start merging more and enable more collabora on. The configura on of these spaces enables and encourages sharing and exchange. As they progress even further they move to the groundfloor where they have the opportunity to use their acquired individual and collabora vely acquired knowledge to produce something that would be exhibited, a tangible tes monial of what was achieved during their years of educa on.â&#x20AC;?

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PARTI DIAGRAM PLAN

Iden fica on of technical and academic wings

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PARTI DIAGRAMS SECTION

Iden fica on of technical and academic wings

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PARTI DIAGRAM PLAN

Iden fica on of a space of interac on between the two wings.

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PARTI DIAGRAMS SECTION

Iden fica on of a space of interac on between the two wings.

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PARTI DIAGRAM PLAN

The spaces of interac on happen more gradually as the students move further down their academic careers, and spa ally through the building.

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PARTI DIAGRAMS SECTION

The spaces of interac on happen more gradually as the students move further down their academic careers, and spa ally through the building.

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PARTI DIAGRAM PLAN

Inclusion of green areas internally at the entrance/atrium and as outdoor green areas as lawns and balconies.

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PARTI DIAGRAMS SECTION

Inclusion of green areas internally at the entrance/atrium and as outdoor green areas as lawns and balconies.

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PARTI DIAGRAM PLAN

Overall form of the building is skewed to be er take advantage of the wind

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PARTI DIAGRAMS SECTION

Overall form of the building is skewed to be er take advantage of the wind

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PARTI DIAGRAM PLAN

More greenery is added internally to further increase the biophilic quali es of the space.

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PARTI DIAGRAMS SECTION

More greenery is added internally to further increase the biophilic quali es of the space.

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PROPOSED DESIGN

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SITE PLAN

Entrance

Service entrance

Main artery leading to and from Ebene. Heavy circula on happening both days through the day.

Orienta on of site and form of building op mised to catch sou-east trade winds

Original image @ 1:500 Scaled 25%

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GROUND FLOOR PLAN