Tango Bo01 Housing

KEY ENVIRONMENTAL ASPECTS:
The energy concept is based on minimum consumption, renewable resources, and the balance between energy production and consumption. Bo01 incorporates Sweden’s largest urban application of solar energy. Energy and drainage systems work together through heat recovery and biogas generation, utilizing the technology of storing heat and coolants in underground reservoirs. Calculations show the block has a green factor of 0.62.

A custom IT network monitors the details of power and energy use throughout the day. Vacuum-tube insulated solar panels provide heating and cooling for the building, and produce more than 100% of the building’s energy needs. Sod covered roof surfaces provide insulation, replenish oxygen to the atmosphere and slow water runoff during heavy storms. The landscape planning combines biology and sustainability to extract underground pollutants; rainwater from roofs is recycled to irrigate water gardens. The planning of this pedestrian block emphasizes alternate means of arrival other than automobiles.

The Tango building was our first fully sustainable project. When we began the project, Sweden was farther advanced than the United States in use of sustainability techniques, and the Swedish government wanted this to be a sustainable project. The knowledge we learned from our Swedish colleagues, such as systems of water cleaning, have since been applied to projects in the United States. Some of the technical aspects of “smart technology” are not necessarily relevant to the future, but others are. It’s fun and useful that the refrigerator can regulate its contents, and be programmed to order fresh supplies when needed, but more useful is the ability to reserve the community room or guest apartment through the internet, or turn on your home’s heating before leaving the office on a cold wet night.

SITE ECOLOGY
Tango’s courtyard garden restates Bo01’s ethos as island amid marshland: a small elliptical public terrace set into a wet garden of mosses and tall grasses reminiscent of the geography and flora of the nearby Öresund. Before construction began on the former brownfield site, the city treated the polluted soil, then laid five feet of clean dirt on top. The landscape planning combines biology and sustainability to extract remaining underground pollutants. Trees and grasses, selected for their ability as bioremediators, trap metals and pollutants, and absorb toxins to further improve the quality of the soil. Vertical planting behind the towers increases the green area. Precipitation on the site is 100% managed:--most rainwater from roofs is recycled to irrigate water gardens, and all rainwater from the roof and the garden that is not used in the planting areas is sent to a “wetlands” that surrounds the oval in the courtyard. Run-off water from surfaces (metal panels, paving, concrete) is directed into a perimeter channel, brought into a central cistern and cleaned.

COMMUNITY DESIGN & CONNECTION
As a pedestrian neighborhood, the planning of this block emphasizes alternate means of arrival other than automobiles. By planning with a holistic view of environmental matters, inhabitants will be inspired to make environmentally friendly decisions in their choice of transportation. Tenants walk, ride bicycles, or take public transportation within this urban area. Other than delivery/drop-off areas, there is no designated parking for cars in the Tango complex—the only “parking garage” is for bicycles! This leaves ample room for the central courtyard and garden, which acts as a public meeting space, especially in the warmer months.

Automobile parking is available only in a city lot. Access to public transportation is facilitated through the building home page (for example, the computer can report the precise times at which buses will leave). Other types of road information that are planned include a booking system for car pooling, interactive cycle maps and travel-planning tools.

WATER USE
For the most part, potable water is used only within the apartments. Given that the building is fairly recently occupied, we have been unable to obtain figures from the Swedish client as to how much potable water is utilized in the units. With an annual rainfall of about 55 inches, sufficient collected rainwater is recycled to irrigate the water gardens. The Tango roof consists of a large section of green sedum which holds rainwater and lessens flooding. All the rainwater from the roof and the garden that is not used in the planting areas is sent to a “wetlands” that surrounds the oval in the courtyard. A well in the outer edge of the wetlands acts as an overflow shield in the courtyard. Run-off water from any surfaces (for example metal panels, paving, and concrete) is directed into a perimeter channel and then brought into a central cistern and cleaned. Finally, the cleaned water is returned to the ocean. During a strong rain, the surplus water is led out from the yard via the well to the common run-off water system in the street to the west.

ENERGY PERFORMANCE
Advanced 2-megawatt wind turbines and photovoltaic systems supply the district’s electricity. Tango’s vacuum-tube insulated solar panels are sufficient to provide heating and cooling for the entire building, and produce more than 100% of the building’s energy needs. With a nod to traditional Scandinavian sod roofs, Tango’s sedum roof surfaces provide additional insulation, replenish oxygen to the atmosphere, and slow runoff during heavy storms.

All glass areas are triple-glazed to provide insulation. Their R-value measure of thermal conductivity is about 6.5, as compared to the 1.5 to 2 for typical American double-paned glass. Two outside layers encapsulate transparent aragon gas, forming a “blanket”. The two inner layers are vented to allow fresh air to pass through. This air is warmed as it passes the aragon layer on its way inside during cold weather, and conversely cools the building during warm weather.

One interesting feature common to all the plans is the Intelligent Wall. Framed of demountable cabinetry, it runs through the middle of the plan, providing each unit with the services of a custom-designed information system, which monitors the details of power and energy use throughout the day—a treasury of information to help residents and the management streamline their energy profile—an eminently sustainable idea.

ENERGY SECURITY
Advanced 2-megawatt wind turbines and photovoltaic systems supply the district’s electricity needs. Tango’s solar panels provide heating and cooling for the building, are vacuum-tube insulated to be functional in cold weather, and produce more than 100% of the building’s energy needs. The excess energy is sold at a premium to the regional electric company, and then sent back via district heating at a lower cost. Exact usage figures are unavailable at this time, but will be available shortly. Energy and drainage systems work together through heat recovery and biogas generation, storing heat and coolants in underground reservoirs.

Remote-controllable wall-mounted ventilators draw in fresh air to keep the rooms from getting stale. All windows are operable by remote control, but can be manually operated as well. In addition, the building has its own generator with storage, in the event of a grid power failure.

MATERIALS & CONSTRUCTION
Bo-01 avoids using environmentally dangerous substances. Materials that reduce the quality of sewer water or sludge are not permitted in areas where there is a risk of leakage into the drainage system. The area is provided with sludge extraction--nutrients are extracted from treated sewage at a local plant, then used in agriculture. Materials and methods that facilitate recovery and recycling during any future demolition were used. All building materials were evaluated and reported using life-cycle methodology.

Emphasis on ecological sensitivity was used during the material selection and building process in order to drive development toward more environmentally appropriate, power and resource-saving materials, products, and systems. Material selection and product purchasing was carried out in collaboration with the City of Stockholm, which arranged competitions between various manufacturers emphasizing performance specifications. To ensure an environmentally appropriate building process, all contractors and suppliers worked according to an environmental management system.

LIGHT & AIR
The apartments have fully developed automatic systems that can direct all electrical functions via the internet. Tango is also prepared for future supplements and changes to the existing technology. Each apartment has a special IT service cupboard, most often located in or near the kitchen. All technology that services the apartment is found inside. Climate, security, and lighting can all be controlled and monitored through this system.

Daylighting and lighting supplement/complement one another in a harmonious way to allow full daylighting of the building. The construction of the windows with build-in-air vents brings fresh air into the apartment throughout the day, allowing the building to be completely ventilated and cooled with operable windows.

Rust-free and allergen-free breakers and sockets and other environmentally correct, halon-free, and sustainable products have been used. With a thought to the high level of technology in the flats, the distribution board has built-in shields, with precautions so that the electro-magnetic field shall not affect the tenants.