This Issue
 
Architects around the world look to the past to introduce bioclimate strategies in designing greener buildings.


WRITTEN BY Alison Gregor

bioclimatic-design-feature4

Some of the best new green buildings are those that challenge our ideas of conventional architecture—but don’t challenge the environment. Building designs that embrace and respond to the local environment, called bioclimatic architecture, as opposed to trying to thwart nature with mechanical systems, are seeing a 21st-century revival.

 

Much of the world’s architecture, prior to the 20th century, responded to the regional climate and could be considered bioclimatic. “If you look at older buildings, you see that people were very good at adapting to climate to get the maximum performance, but we kind-of got lazy once air conditioning and electric light came along at the turn of the last century,” says Patrick Leonard, the director of Paladino and Company, a green building consultant based in Seattle.

 

Over the course of centuries, builders around the world had refined different types of bioclimatic architecture, particularly in regions such as North Africa, the Middle East, Southeast Asia, and Europe. For instance, the traditional Spanish hacienda design uses thick, thermally dense walls to retain heat or chill, thereby regulating temperature and creating a stable indoor microclimate, says Sam Kimmins, the principal sustainability advisor for the Forum for the Future, a global sustainable development organization based in London.

 

The haciendas have “small windows to reduce solar gain, or overheating, to the south, and larger windows to the north to bring in light,” he says. Similar thick-walled structures are found in ancient Greece, Yemen, and other regions.

 

Leonard pointed to the traditional high-peaked, curved roofs in China and Japan, developed to control stormwater and snow, as well as the indigenous architecture of Hyderabad, Pakistan, which has a structure designed to capture winds and channel air flow for natural ventilation.

 

Sod houses built by Scandinavian and Nordic cultures hundreds of years ago were some of the first bioclimatic structures to integrate vegetation, says Bruce Dvorak, a professor in the Department of Landscape Architecture and Urban Planning at Texas A&M University. “With stone and timber and other supporting materials, the sod formed the bulk of the walls and insulated the house,” he says. “Live sod was also placed on the roof. The living sod on the roof shaded the building during the summer and insulated the house during the winter.”

 

bioclimatic-design-feature3

By the late 19th century, much of the world’s architecture had evolved to use characteristics of the building site and building fabric to create a comfortable internal environment, Kimmins says. Some tactics used were air flow across ponds to create natural cooling; plantings to create shading; a stack structure to bring about natural ventilation; or orienting rooms in different directions and adapting window sizes to regulate temperature.

 

With the advent of modern technology in the 20th century, contemporary design trends shifted away from being responsive to natural conditions and emphasized instead isolating buildings from nature to try to overcome those conditions. The evolution of technologies to thwart nature wasn’t necessarily a bad thing, Leonard says.

 

“I think it’s a great innovation that we don’t have to be climate-adaptive, because it opens up a lot more of the world for trade and commerce and just being habitable,” he says.

 

Still, the evolution of new technologies and spread of “international style” architecture have created situations where, for instance, the glass office towers so popular in Western cities are built in desert climates that turn them into greenhouses. In some instances, there are even so-called “green” buildings constructed that have little or no responsiveness to the environment.

 

One of the latest trends in architecture is to use new technology to enhance, amplify, and measure the performance of traditional bioclimatic techniques.

 

“I think now we’re more focused on resource conservation and using what’s locally available, so we’ve got an opportunity to take the best of both worlds—in other words, how do we apply new technology to help us climate adapt?” Leonard says.

 

One example is a case of biomimicry in Harare, Zimbabwe, where a mid-rise building without air-conditioning was designed to stay cool with a termite-inspired ventilation system. Scientists digitally scanned termite mounds to map their architecture in three dimensions, and then architects and engineers applied the acquired knowledge about tunnels and air conduits to create a blueprint for self-regulating buildings for humans.

 

Another recent case is the U.S. Embassy in Monrovia, Liberia, which could have been an example of the worst kind of climate-blindness, but instead the government chose to respond to the local climate in modifying its typical building prototype.

 

“The Department of State has a standard embassy design, which can be deployed anywhere in the world, but if you don’t adapt it for climate, you’re basing your design off a Washington, D.C., building,” Leonard says. “So it was a really big move in Monrovia to take this standard embassy design and make it climate-appropriate and responsive to the location.”

 

The embassy, which is LEED Gold, is located in a hot, humid, high-rainfall location, so it uses waste heat for cooling, rainwater for drinking water, and extensive photovoltaic electricity generation to enhance energy security.

 

“With fairly minimal modifications, you can make the building way more efficient,” Leonard says. “Even things as simple as, while you insulate the wall cavity in Washington, D.C., in Monrovia we’ve found if you use less insulation in the wall, you get a more efficient building, because you don’t want to retain any heat.”

bioclimatic-design-feature1-300
bioclimatic-design-feature5-300
bioclimatic-design-feature6-300

Renderings: Traditional architecture in Sana’a, Yemen; a Scandanavian sod-roofed house; a mashrabiya and detail of the wooden screen; a wind tower from Al Bastakiya in Dubai.

MGLM Architects. www.mglmarchitects.com

The sand dunes of the Algerian Desert served as inspiration for a new government building to be constructed in Northern Africa.

Mario Cucinella of Mario Cucinella Architects in Bologna, Italy.

Mario Cucinella of Mario Cucinella Architects in Bologna, Italy.

The sand dunes of the Algerian Desert served as inspiration for a new government building to be constructed in Northern Africa. Though the nine-story office building, which will serve as the headquarters for the Autorité de Régulation de la Poste et des Télécommunications, is in coastal Algiers, somewhat removed from the Algerian Desert, Mario Cucinella Architects of Bologna, Italy, studied the local climate carefully in designing the structure.

 

The three-sided, dune-shaped building is serving both as a cultural and geographic emblem of Algeria, but also as a prime example of bioclimatic architecture. The building’s slightly concave southeastern side scoops up cool, fresh winds from the Atlas Mountains while the its convex sides to the northeast and southwest serve to deflect hot winds blowing from the direction of the sea, said Alberto Bruno, who handles environmental design at Mario Cucinella Architects. Office windows designed to be open enable the building to breathe, and warmer air rises and exits at the top. “The shape of the building was derived and defined according to wind analysis to get the maximum natural ventilation for indoor and outdoor spaces,” Bruno says.

 

Another influence on the shape of the building was a desert structure used in antiquity in many arid parts of the world, called a tu’rat, Bruno says. These crescent-shaped structures, made of stones piled without mortar, captured moist winds and fog, which created condensation that percolated down to irrigate protected gardens.

 

“In the early morning, you can collect a little bit of water, and this allows you to grow plants,” he says. The tu’rat-inspired structure includes the enclosure of a small oasis of palm trees and other vegetation on the south side of the building.

 

In a region where summer temperatures regularly reach 95 to 104 degrees Fahrenheit, the evaporative systems help to keep the air in the oasis comfortable and cool, a natural passive cooling technique frequently seen in the traditional architecture of Arab countries, Bruno says. “They designed buildings that were able to catch hot and dry winds, humidify air by evaporating a small amount of water, and provide fresh air without any other technology. You can cool the air by five or six degrees. Without needing to use energy or chillers, they were able to make a comfortable space in a very hot climate.”

bioclimatic-design-feature8

Besides its structure, the second important bioclimatic feature of the building is its skin, Bruno says. “The southwest and northeast facades are like screens,” he says. “They are made of crossbeams and perforated panels, and this system allows us to use shading to reduce by 80 percent the solar radiation with the facades, so it’s very effective.”

 

Besides reducing the risk of overheating in the summertime, the facades also serve as a reminder of the regional culture. “The facade is similar to a mashrabiya, a traditional Arab screen, so we tried to make something that is very empathic with the local culture, something connected with the people,” Bruno says.

 

The building’s southeast facade has photovoltaic panels that power the air conditioning. The panels are integrated into louvers that serve to shade the building’s interiors, while a generous-sized hole in the facade creates a canon lumière, or lightwell, allowing sunlight to tunnel into the building’s interior down to the ground floor. The lightwell will be angled so that, for warming purposes, solar radiation penetrates the building from the autumn equinox until the first day of spring, but is deflected during the summer months to keep the building cooler, highlighting the deep connection between the building design and the local climate.

 

The building will cut energy consumption by 79 percent compared to a standard Algerian office building, Bruno says. Through the use of rainwater collection and phytopurification (a constructed wetland), potable water demand should be reduced by 77 percent, which is critical in a desert, he says. “We’ve just finalized the schematic design and, thanks to a thorough optimization, the building is performing better than we originally thought.”

 

While Bruno says he couldn’t yet comment on the total project cost, construction is anticipated to begin in 2015. Architects continue to analyze the building’s predicted environmental performance, though it’s safe to say that any bioclimatic strategies they use are above and beyond what is required in Algeria at the moment.

 

“In Algeria, they’re still working on regulations related to sustainability, energy and the environment, and also some tools to evaluate building performance,” Bruno says. “We’ve been told in the next few years, they’ll have these regulations.”

bioclimatic-design-feature7

The building was conceived as an icon where tradition and modernity, both in form (derived from the pointed arch typical of Mediterranean architecture and the incline of the solar diagram) and in the treatment of the surface of the envelope.

 

The project emerges from the desire to create a building that works according to the principles of bioclimatic architecture, and in particular by the natural cooling techniques of the past, such as the tu’rat, has suggested an aerodynamic shape, convex on the North to divert hot winds at midday, and concave to capture the cool breezes at night, and thus promoting the natural ventilation of the building.

 

Renderings: MIR, Engram Studio

The building will be the first to use photovoltaic panels for its own electricity production.

The building will be the first to use photovoltaic panels for its own electricity production.

Immersed in the heat and humidity of the jungle and the sea, an old building in Rio de Janeiro is being completely rejuvenated using bioclimatic and other green strategies to transform it into one of the most sustainable office towers in Brazil.

 

The project, called RB12 after its address at 12 Rio Branco Avenue, is a 21-story conversion that began construction in January in Rio de Janeiro’s Porto Maravilha district, an area that’s undergoing a renaissance of its own with more than five million square feet of redevelopment. Designed by the French-Brazilian architectural firm Triptyque and constructed by Natekko of France, RB12 will have a façade that can be opened to the elements, in contrast to other office buildings in the city that are fully sealed off from the climate.

 

A façade of double-glazed glass will optimize the use of daylighting with angled windows that should make the building glitter like a diamond, while louvered stainless steel panels control the amount and quantity of sunlight, explained the architects at Triptyque in a joint email response to questions. Suspended gardens integrated into the façade, along with a green rooftop, also help control lighting.

 

“The building is located in an avenue lined with buildings very closed in on itself,” the architectural team says. “The heat tends to stagnate between buildings, and the sun is directly on the windows because of their height.”

 

The glass façade is strategically shaded to reduce the heat gain in the building from direct solar radiation, but is transparent enough to allow high levels of natural light to enter indirectly and illuminate the building. The façade system “allows a reduction in the use of artificial lighting along the walls, and therefore power consumption and internal temperatures are also reduced,” the architectural team says.

 

At night, the building’s windows are opened to provide ventilation and cool down the building.

 

“The project provides a system for automatically opening windows during the night, which makes it possible to take in the fresh air and keep it all day, thanks to the insulation of the building,” the architectural team says.

 

Though not necessarily considered by purists to be a bioclimatic strategy, a convection HVAC system of active chilled beams will be used to moderate the building’s temperature during the day and provide thermal comfort for workers in the building. The primary advantages of the system are lower operating costs.

 

“The system of chilled beams is becoming a worldwide trend in air conditioning, having been selected by ASHRAE Journal in September, 2007, as the best option for ambient air conditioning when considering the optimization of energy consumption and generating a comfortable environment for the user,” the architectural team says.

 

The developers of RB12 claim that it will be the first commercial building in Brazil to use photovoltaic panels, and a small vertical installation will meet about 18 percent of the building’s energy demand. The tower will also use a regenerative brake elevator that harvests thermal energy from its braking mechanism. And, subject to the approval of local authorities, RB12 will also incorporate fuel cell technologies to convert excess methane gas from the streets into electricity.

 

Upon analyzing all the green strategies used in RB12, architects say they estimate the building will use about 60 percent less energy than a typical office building. And since the building will be producing energy 24 hours a day, but consuming it for about eight, excess energy will be sold back into the electrical grid.

 

“The law to allow this process is currently under discussion,” architects say. “The proposed RB12 is indeed a trendsetter in Brazil, preceding the legislation of the country and generating national changes.”

 

Reduction of water usage is also an objective of RB12, where low-flow faucets will minimize water use, and greywater will be recycled for irrigation of the building’s rooftop and green walls. Triptyque architects say that greywater treatment should supply about 60 percent of the building’s daily water needs.

 

The total construction costs of RB12, which is anticipated to be completed by March 2015, will be about 23 million Brazilian reais, or about $10.4 million, architects say. While RB12 will cost more than a conventional office building, “The project was designed to have an extremely short payback,” architects say.