The VanDusen Botanical Garden, about twenty-two hectares in size, is located in Vancouver, Canada, a few kilometers from the Pacific Ocean, and has existed since the 1970s.
In the south-eastern part of this garden, a new building was erected in 2011 - a visitor center with an area of about 1,800 square meters. It accommodates a lecture hall, a wedding venue and a cafe.
The shape of the building, its energy efficiency and the materials from which it is built - all this suggests that even before the design began, its creators set their goal to obtain the LBC (Living Building Challenge) certificate, but this in no way diminishes the dignity of the building. LBC is much more difficult to obtain than LEED (by the way, the center building is LEED platinum) - LBC requires the building to have zero energy consumption. His requirements for the materials used are also high. Probably, the authors carefully studied the nuances of this certification and only then moved on to the ideas of the building. The symbol of the certificate is a flower with seven petals, each of which represents a specific aspect of architecture: place, water, energy, health, materials, objectivity and beauty.
Legend has it that the Canadian authors of the project - architect Peter Busby, Perkins + Will bureau and landscape designer Cornelia Hahn Oberlander - the idea to create a center in the form of an orchid flower came independently of each other, and that both of them came for discussion of the project with a copy of the page with the image of this flower, taken from the same book. Both authors are adherents of green architecture. Mrs. Oberlander is even considered a pioneer in rooftop landscaping, which she began to create in the seventies of the XX century.
So, the center is made in the form of an orchid, and its roof is in the form of wavelike and partially overlapping petals. The roof is spread over a one-story, almost entirely glazed building. One of the "petals" gently descends to the ground, creating a path that allows small animals to climb up.
The green roof, which is planted with over twenty species of plants, reflects the herbaceous vegetation characteristic of the Canadian Pacific coast. Sedge (Carex acuti-formis) and rump (Juncus) grow on flat surfaces, and yellow irises (Iris pseudacorus) and camassia (Camassia) grow on slopes. These plants effectively break down ammonia, nitrates and phosphates, so they participate in the purification of rainwater. Drought-resistant febrile grass is planted on steeply sloped roof sites. Thanks to this variety of plants, the roof of the center has become a habitat for many species of birds and insects.
If earlier the main tasks of the botanical garden were the preservation of plants and the promotion of biodiversity, now they have been added to the promotion of energy efficiency and environmental technologies.
Everything in the building of the visitor center is subordinated to the ideals of the LBC: the building uses its own renewable energy sources, and the water for the building is taken from the sludge and reused after purification without the use of chemicals.
In the center of the building, there is equipment that provides air circulation and cooling of the building. The twelve-meter high walled atrium includes a solar aerial power plant made up of self-sensing windows and an aluminum heat sink. The sun shines through the atrium, heats the aluminum heat sink and draws air out, cooling the lower parts of the building through convection. It was decided to perforate the aluminum, making many 3mm holes to increase the surface area. When the windows are open, the perforation allows for through ventilation.
Wide, partially overlapping roof petals prevent heat gain while protecting the building from rain. Its thermal insulation is roof greening, and four of the six roof petals are greened. The remaining two petals are covered with a standard roof. One of them supports pipes of water heated by the sun, and the other is inverted so that it can collect and drain water into a cistern with a volume of three hundred thousand liters, located under the building in the easternmost "petal" of the roof. This water is filtered and used for flushing toilets. After that, it is cleaned and sent to its own bioreactor located in the northern part of the building. There it is processed with the help of microorganisms, then purified using a filtration pad, and then used to water the gardens around the building. Surplus water from all roof petals is collected in another tank and sent to a drainage well.
The City of Vancouver requires drinking water to be chlorinated, so the VanDusen Botanical Garden Visitor Center is connected to municipal utilities. At the same time, chlorine is on the LBC's "red list" of prohibited materials, so the architects had to negotiate with the management of the certifying company to make an exception to the rules when considering this project.
The team placed four hundred solar water pipes on the north side of the building's roof and on a nearby building to avoid shade from trees. Pipes accumulate heat from the sun and store it in water, which is used to heat the building. A radiant panel heating system built into a floor of concrete slabs drives hot air around the perimeter. Part of the water heated by the sun's rays heats the liquid in the radiant heating system. Surplus water flows into 52 wells 60 meters deep, which are randomly located around the building. This water is stored at a temperature of about 20 ºC and helps to heat the outside air in winter and cool it in summer.
In the parking lot at the entrance to the building, there are photovoltaic solar panels that provide 11 kilowatts of electricity - this volume covers from twenty to twenty-five percent of the electricity needed for the center. Thanks to the flow of daylight from the atrium and the glazed wall, as well as LED lighting, energy consumption for lighting remains low.
Most of the energy is spent on the café, and to achieve zero energy consumption, the visitor center trades surplus hot water heated by the sun for electricity generated by an improved air conditioning system in the adjoining restaurant building. This allows all the energy to be generated on site while maintaining carbon neutrality.
LBC also regulates the choice of building materials - there is a "red list" of materials that LBC does not tolerate, as it is recognized that they have a negative impact on the environment and human health. Therefore, simple materials were chosen for the construction of the center, which determined the strict forms of the building: the eastern part of it is made of earth and concrete walls, and the floors are made of polished concrete.
Due to the same “red list”, it was necessary to abandon the ready-made perforated PVC drainage pipes in favor of pipes made of acrylonitrile, butadiene and styrene plastic, in which thousands of holes were drilled specifically for this site.
The main building material for the building itself was wood, the use of which prevents the growth of carbon dioxide in the atmosphere. Wood in the visitor center is used very widely - from roof structures to the exterior of the building, furniture and interior elements. Moreover, the Living Building Challenge prescribes the use of only those wood products that are certified by the FSC Forest Stewardship Council, and also sets a high minimum threshold for the proportion of processed products used and requires materials to be supplied by local producers, since in this case, you can do without long-distance transport. …
The roof of each of the six petals was assembled from factory-produced timber panels made from FSC-certified laminated plank beams. At the same time, thermal insulation, electrical equipment and fire protection devices were pre-built into the components of the roof to facilitate its installation, which was carried out in winter.
The wooden roof was equipped with a leak detection system and was complemented by a two-layer bitumen membrane, waterproof and plant root resistant. The pitch of the roof varies from two to fifty-five degrees, and since parts of the roof with different angles of inclination require different drainage, irrigation and shear resistance, it had to be landscaped in several ways.
ZinCo was tasked with greening the roof and came up with a three-system solution. The protective and irrigation layer BSM 64 was integrated over the entire roof area. Where the angle of inclination of the roof was less than ten degrees, a Floradrain drainage and water storage element was integrated® FD 40. Where the angle was more than ten, but less than twenty-five degrees, special Floraset elements were applied® FS 75, which provide sufficient adhesion to the substrate, and the shear force is redirected to the eaves. Where the angle of inclination of the roof is above twenty-five and in some places reaches fifty-five degrees, Georaster elements are applied® 10 mm high, filled with the bottom layer of soil. Additional barriers against soil shear are here completely absorbed by the shear forces. When determining the size of the cornices and barriers, the increase in the load on the roof due to soil moisture and heavy snowfalls was taken into account.
The green roof not only accentuates the unusual architecture of this flower-like building, but also serves as one of the factors to ensure the “LBC Ideal”, because buildings with zero energy consumption and carbon neutrality are the future.
The representative office of ZinCo in Russia - TsinCo RUS - has adapted ZinCo technologies to the climatic conditions of Russian regions and has been successfully using them at sites from St. Petersburg to the Urals for more than ten years.
