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Steps and challenges to design a sustainable building in tropical environment

One of the projects of our foundation is to share information on sustainable construction in the Tropics and to build a model house that can inspire all builders in Bali and elsewhere in the world under the same latitude.

The first point, totally cultural, is to get rid of this symbol of modernity that is air conditioning. Air conditioners not only represent 10% of global electricity consumption but they release refrigerants which are powerful greenhouse gases. We build without thinking about the orientation of the building, its envelope, its openings because we know that with air conditioning, we will maintain thermal comfort in the building. But in doing so, we all know that our ecological footprint condemns future generations, we now speak of temporal colonization because we steal the resources of our descendants.

© GreenGreat

In 2023, we continue in Bali to build concrete bunkers painted in black with large windows exposed to the sun that run the air conditioners. And yet, concrete not only stores heat but has a high carbon footprint during its manufacture. Black paint on a tropical building is an environmental aberration because it traps heat. And finally large unshaded bays also contribute to the storage of heat and do not allow air to circulate. And in Indonesia, where more than 60% of electricity is produced with coal, the more electricity we use, the more greenhouse gases we emit and the more we contribute to social and environmental problems.

The new credo is porosity, an old principle that urgently needs to be brought up to date, the circulation of air in buildings.

The second point to keep in mind is the word bioclimatic. Take into account sun exposure (in Bali, orient buildings east-west and completely reduce openings to the north) and wind orientation (in particular the wind) and assess the air flows in the building (calculation of the air flows linked to the climate motors, calculations on some air speed zones).


The third point is the Negawatt approach. Applied to a various energy-consuming equipment, this strategy provides a rigorous methodology to recover as much as possible:

  • Passive or active recovery of climatic elements to meet energy needs.
  • Sobriety in the operation of the installations or in the appropriation of the operation by the users.
  • The efficiency and optimization of the envelope components and the necessary equipment for the operation of the building.


The fourth point is the overall cost. The initial investment, decisive criterion for the client, must be put into perspective and put into perspective on the life of the building by integrating the costs related to operation, maintenance, upkeep and exploitation. This approach can value some over-investment by saving building lifetime.


The fifth point is the carbon footprint the energy content of the building (embodied energy) for its construction represents the equivalent of the energy consumption of several decades of operation of the establishment. Similarly, the choice of location for a project can be decisive if the environmental cost of transporting people is considered.

The analysis of the site naturally includes different criteria:

  • The physical environment topography, soil type, hydrology, natural disasters (landslides, earthquakes, etc.) and soil pollution
  • The climate: exposure to the sun and shade (neighboring buildings or existing vegetation), prevailing winds
  • The shipyard: riparian, waste recovery
  • Biodiversity: existing fauna and flora
  • Proximity nuisances: acoustic, visual, odor, electromagnetic field – relay antenna or high voltage line)
  • Local resources: sustainable energy, local materials, local facilities and services

Once this site analysis has been carried out, the two main guidelines for drawing the construction plan of the building are the thermal and aerolic zoning consistency, in other words how to protect yourself well from the sun and how to best circulate the air to cool the building either with the prevailing winds or by pressure difference.

Here are the general principles of bioclimatic architecture adapted to Bali (8 Degrees South):

  • Natural ventilation (separated building mass, porous opening, high ceiling)
  • Solar shading (movable shading, building self-shading, double roof)
  • Day light (light tube, light shelf, sky light)
  • Micro climate adjustment (pond, landscape)
  • Roof insulation (white roof)
  • Heat capacity (high mass in day time, lightweight in night time)
  • Nocturnal radiation (high emissivity material)
  • Stack ventilation (chimney effect)
  • Evaporative cooling (with caution)
  • Orientation (East-West, blind on the North)
  • Stilt construction to promote air circulation.

Concerning the building envelope, here are the main points to consider:

  • Limitation of the direct light
  • Optimize natural ventilation
  • Controlling air permeability
  • Thermal insulation on the exposed wall and the roof

Finally, of course, a bio-climatic house takes into account the rainwater harvest and also produces its own energy:

  • Collect rainwater and store it in tanks. Big problem of water resources in Bali, contamination of groundwater.
  • Install solar panels because it gives us a guaranteed price for electricity for 20 years (their lifespan)

Science without conscience is only ruin of the soul and the immoderate use of concrete and air conditioners in the Tropics is an ecological aberration. It is time to look for viable alternatives for construction, to draw on the past while adapting low-tech techniques with contemporary designs, that’s the responsibility of every architect, every builder and every client and it is the fight of the Greengreat Program and the Ocean Gardener Foundation.

Eloy LARCENA
Construction Engineer

Sources :

International Shading design strategies within the Tropical Modernist Nigeria: Lessons for Nigerian Designers, in ijird.com, June 2015

 

Manuel de bonnes pratiques architecturales. Eco-construction et efficience énergétique dans les Bâtiments, CTB Sénégal, June 2017

 

Conception Architecturale Durable en Milieu Tropical, ONU Habitat, Institut de la Francophonie pour le Développement Durable, 2015

 

Tropical Sustainable Architecture, Social & Environmental Dimensions, Joo_Haw Bay & Boon-Lay Ong, Architectural Press, 2006

 

© GreenGreat April 2023

10 Questions To Better Understand Bamboo Challenges For The Future

Meeting with Olivier Betting, head of Asali Bali, one of the main companies based in Bali and specialized in bamboo construction engineering in Indonesia and abroad.

As a steel structural engineer, how did you come to use only bamboo to construct buildings?

It is a personal journey, also linked to the impact of my original profession. Metal and concrete require a lot of energy, it also contributes a lot to greenhouse gas emissions. Not to mention the extraction of sand which also devastates rivers and beaches. Bamboo has phenomenal mechanical qualities to the point that the span reached 45 meters for a bridge in Columbia and 35 meters for International Bamboo and Rattan Organization’s building in China. If we take the necessary precautions, bamboo is solid and durable, and in addition it allows architectural audacity at low cost. From my carpenter grandfather and my mother, a wood structure teacher, I was made aware of the preservation of our resources from an early age as well as the alternative solutions that we can develop, or rather reinvent in a modern context.

Alam Atelier

So, tell us the limits of bamboo and the precautions it requires for its implementation

Being an organic material, bamboo is subject to humidity, insects and UV rays. It seems prohibitive but in fact, we can live with it provided we treat it well and arrange it. Against insects (and in particular Powderpost Beetle more than termites), it is treated with a natural salt, borax borix, for 3 days. Against the humidity favorable to the development of fungi, you must make sure to dry your bamboo until the humidity level drops below 20%. We usually say that bamboo needs boots and hat, which means that it must not be in contact with the ground to avoid water and splashes of humidity associated with washing soils. Bamboo is naturally protected by a layer of silica which is sensitive to UV sunlight, so avoid exposing it to direct, overhead sunlight. This is why in general we overhang the roofs so that the sunlight does not penetrate more than 45° into the structure.

Tea house Bali
Umani Bali

How durable is a bamboo structure? Do you guarantee it for at least 10 years?

Yes, we guarantee it for 10 years provided that our customers take out a maintenance contract equivalent to 10% of the construction price (1%/year). Out of 1.000 treated bamboos, there are on average 3 which contain insects and which should be treated or replaced. It is a risk, we do not hide it. It is advisable to check visually (twice a year) that the structure is aging well, this can happen faster than on a metal or concrete structure if you do not take care of it. However, a metal structure exposed to rust or a concrete wall exposed to humidity can also be subjected to the natural elements until it breaks.

 

Have all your customers embraced the trend of bamboo or do they simply see it as a financial or even purely aesthetic interest?

I think it’s the aesthetic that takes precedence, no need to hide it in the age of social networks. Bali has become the showcase for bamboo construction in the world with dozens of buildings, each more breathtaking than the next. Then, I would say that it is the financial argument. For example, we are in talks with a Turkish company investing in the Maldives which prefers to build with bamboo from Bali rather than wood from Russia, it is much faster to implement and it offers more possibilities in matter of architecture. For our part, we charge around 3 million IDR (200 USD) per square meter for the construction in Bali including bamboo structure and roofing (Foundations, MEP… not included) it is very competitive. The business plans are calculated over 20 years, there is real profitability with bamboo.

 

Ekommunity

So precisely, why has Bali become the world reference in bamboo?

It was Linda Garland in the 80s who gave the impetus with her Environmental Bamboo Foundation. The torch was taken up by John Hardy with the construction of the Green School in the 2000s. During the last World Bamboo Congress held in Vietnam, it was noted that it is in Bali that we find such an emulation, people are very envious of the level of finishing and the architectural innovations. Whether in Colombia, the Philippines, Thailand and even Vietnam, companies specializing in bamboo are involved in a fairly limited range of action.

But, it is more than important to underline that all this is based on an artisanal know-how still present in Bali, in particular in Belega in the Gianyar region where our company has been established since 2009. We build a lot of bamboo in Bali always and there is therefore a workforce that perpetuates a very qualified traditional know-how to implement the bamboo but also to cut and treat it. As often in Bali, it is the encounter of foreigners with highly qualified Balinese craftsmen that makes it possible to achieve this level of excellence and this is the main reason for the success of this bamboo construction sector.

 

Does Bali produce enough bamboo for the needs of this booming industry?

Unlike Java or China where there are plantations for the bamboo industry, the bamboo we use comes from small producers and forests, thus avoiding monoculture land. Bamboo being a grass, as soon as a cane is cut, it will grow back (provided that the roots are not cut). Bamboo grows very quickly, 40 to 60 cm per day and can reach 20 to 30m between 3 and 6 months But it is only after 3 years and sometimes 5 years that it can be cut, we must wait until its walls have thickened (9% of the diameter) It is cut during the new moon and dry season. It is therefore understandable why it is a first-rate ecological product, not to mention that it sequesters carbon even better than trees (30% more than a deciduous forest) and that its end of life does not pose a recycling problem.

 

What are the different products made from bamboo?

First of all bamboo poles which measure up to 12m long with a maximum diameter of 15cm, pieces of choice for making beautiful structures. Then, inspired by all the local craft techniques, we cut it into slices, lengthwise, in all directions. It is gathered in bundles to give these organic shapes to the frames. We even make tiles with 7 layers of bamboo/m.

Why are there mainly yoga shalas, hotel lobbies, restaurants, bungalows and so little individual bamboo housing?

Although there is a growing demand for individual housing, we have not yet worked on turnkey solutions for individuals. We specialize in bamboo structure only. Our goal is to bring our knowledge of large-scale bamboo buildings in order to professionalize practices and change the perception around this material such as the lobby that we are building in Sumatera which will be the largest building in bamboo in the world ever realized (3122m² of roof, opening planned for new year 2023).

 

Why all these mock-ups in your workshop?

We are one of the few companies in the world to specialize in bamboo with 4 structural engineers working permanently but you never see the rendering as well as with a mock-up. We generally start with an intention mock-up to imagine a form that sticks to the desires of the client, to the topology of the land and the project. And then, once the calculations are finished, we will produce a mock-up on a scale of 1/50th in general (2cm=1m) which includes exactly the number of bamboos that fit into the construction. This is essential because sometimes the 3D design does not render certain curves precisely enough, it helps us a lot to visualize the project with the client as well as to communicate with the teams on site.

Beluna Ubud

What is your dream for the future?

Building a bamboo airport would change people’s perception of this material and contribute to modifying mentalities on ecological and sustainable solutions, we already have the plans [smiles]. The next step is to set up other entities around the world to promote Balinese know-how and bring our expertise to use local resources in each environment.

ASALI BALI
https://asalibali.com/
Jl. Padat Karya No.9, Belega, Blahbatuh, Gianyar, Bali

More info on bamboo construction in Bali
STUDIO WNA https://studiowna.com/
PT.BAMBOO PURE Ibuku.com

Why is solar energy having such difficulty breaking through in Indonesia?

Courtesy : Inecosolar

In recent years, an effort had been made by PLN, the national company which has the monopoly of distribution and sale of electricity in Indonesia, to allow the export of electricity produced by the solar panels of individuals which is not self-consumed, this is called Net Metering. When you produce more electricity than you consume, it goes to the national grid and your meter runs backwards to reduce your bill and enhance your investment. The power of the solar installation was limited to the size of your subscription / grid connection: if you had a 5.5kVA meter, you could install 5.5kW solar power (alternating current). The bill was never zero since there was a minimum monthly fee due to the connection to the network.

A brake on Net Metering in March 2022
But last March 2022, PLN changed the situation and now only accepts a maximum of 15% of your subscription, which has put a sudden brake on the installation of solar panels in Bali and everywhere else in Indonesia. PLN surprised everyone as it contravenes government regulations. So why this shift? And this general impression that renewable energies are not developing as fast as they should in Indonesia? Let us remember on this occasion that the Archipelago is home to the largest geothermal deposit in the world, a carbon-neutral energy, but that geothermal energy only represents 5.2% of the electricity produced in Indonesia1.

The only reason for the reversal of PLN and the slow development of renewable energies in Indonesia is coal. Indonesia is the world’s second largest producer behind China and ahead of India, its production has increased by 9.2% in 2021 and by 74% since 2011. We can of course deplore that countries continue to extract coal and to burn it in their thermal power stations because this highly polluting material contributes to 42% of greenhouse gas emissions. It will of course be objected that the economic reality and the low cost of coal explain its intensive use and its development, especially in Asia.

Conflicts of interest in coal mining at the highest government level.
But in Indonesia, the situation is made even different by the conflicts of interest as they were highlighted by an extraordinary documentary filmed in 2019 and entitled SEXY KILLERS2 which is easily found on Youtube. This documentary sheds light on how the campaign team that brought Jokowi to power has interests in coal, not only owning mines but also thermal power plants.

60% overcapacity of coal-fired power plants Despite Finance Minister Sri Mulyani’s warning in 2017 to the boss of PLN, the national electricity company, PLN has continued to program the construction of coal-fired power plants to the point that Indonesia is at least on the 10 next years in overcapacity of 40 to 60%3. This is the main reason why PLN is doing everything possible to curb renewable energy programs in Indonesia, and in particular photovoltaic solar energy. And when we also know that the energy supply contracts are accompanied by a TAKE-OR-PAY clause, which means that whatever the energy demand, PLN is obliged to pay the supplier, it is easy to understand that the business coal-fired electricity benefits an elite that holds the reins of power.
Courtesy : Unearthed-Greenpeace

Blame is placed on the Japanese and the Chinese
Two Indonesian analysts belonging to the Institute for Energy Economics and Financial Analysis, a very respectable international institution, published in November 2021 a 23-page study titled “Indonesia Wants to Go Greener, but PLN Is Stuck With Excess Capacity From Coal-Fired Power Plants It’s Time for Japanese and Chinese Investors to Step Up and Be Part of the Solution”. We strongly disagree with the angle of this analysis which brings opprobrium to the Japanese and the Chinese and makes no mention of the financial interests of the Indonesian political elite in this energy market based on the coal. As shown in the attached diagram, 41% of shares in private thermal power plants are owned by Indonesian companies, with the Japanese and Chinese coming far behind.

 

Little hope for radical change despite Indonesia hosting the G20 in November 2022 As the G20 summit to be held in Bali in November 2022 approaches, statements abound to announce net zero carbon emission by 20604. But in view of this edifying situation, one really wonders how Indonesia will be able to take a turn towards renewable energies as long as coal will bring as much to people who have functions in the government. Not to mention, as the documentary cited above points out, that the exploitation of coal mines creates desolation: 3,033 abandoned mines have not been filled in as operators are required by law to do, creating lakes polluted with heavy metals and drownings5 ; the barges transporting thousands of tons of coal daily ravage the corals when they park behind certain islands to escape the bad weather; coal-fired power plants pollute and poison the inhabitants…

International Energy Agency – IEA), Key World Energy Statistics 2021 [archive], september 2021, [PDF].

SEXY KILLERS (Full Movie) – YouTube

Institute for Energy Economics and Financial Analysis. IEEFA.  “Indonesia Wants to Go Greener, but PLN Is Stuck With Excess Capacity From Coal-Fired Power Plants” page 9. Ieefa.org

Indonesia’s PLN in talks with investors over early retirement of coal plants | Reuters

5www.jatam.org/en/category/campaign/deadly-coal-campaign/

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