Mecanismos de participación activa de origen comunitario: el enfoque “bottom up” para el

Annual use^b Intensity

Cooling 540,000 kWh 18 kWh/sq m

Heating 1,290,000 43

Service Power 510,000 17

Total Base Building 2,340,000 78

Tenant Power 1,710,000 57

Total Energy Use 4,050,000 135 kWh/sq m

a Skanska, Hagaporten 3 Energy Use. PDF supplied by Jonas Gräslund on September 23, 2011.

b Maija Virta (ed.), in “HVAC in Sustainable Office Buildings,” REHVA Guidebook No. 16, Brussels, 2012, p. 93.

7.67 Left: About 30,000 sq m of office space surround a “light garden” in the center of Hagaporten 3. Photo: Äke E:son Lindman.

At a glance

Name: Hagaporten 3 Location: Stockholm, Sweden Size: 323,000 sq ft (30,000 sq m) Completed: October 2008 Cost: US$130 million

Distinction: Miljöbyggnad Green Building Gold level and EU Green Building Programme

Program: Commercial office

Project team

Owner: Skanska Commercial Development Nordic

EAWAG FORUM CHRIESBACH, Dübendorf

Forum Chriesbach, a 92,000-sq-ft (8,533-sq-m), five-story office build ing in Dübendorf, Switzerland, uses only as much energy as a typical residence, even though it is forty times larger. Occupied by Eawag, the Swiss Federal Institute of Aquatic Science and Technology, the building was designed to be a place for researchers and scientists to learn, study, teach, and, most importantly, collaborate.

Eawag is an international research institute committed to the ecological, economic, and socially responsible management of water.

Naturally, one of the Institute’s objectives for its new building was to incorporate the best water-management practices. The building is named after the Chriesbach stream, which flows to the north of the building. Bach is German for brook or stream, and a forum is a meeting place for discussion. Thus, the name “Forum Chriesbach” not only signifies the location of the building but is also a fitting name for a collaborative knowledge center focused on water science.⁸⁷

Eawag is concerned not only with water, but with all natural resources. Additional requirements for the new building included:

• Energy, materials, land, and funds should be handled frugally.

• Energy use must be minimized.

• Renewable energy sources must be utilized.

• Room temperatures should be 66°F (19°C) minimum and 79°F (26°C) maximum.

• Rainwater must be collected and used.

• Urine must be collected separately from wastewater and solids.

• The site must be landscaped as naturally and integrated with the Chriesbach as appropriately as possible.⁸⁸

When planning the building, the construction techniques and technology selected pushed available systems to their limits. For example, the building uses only onethird of the energy of a con -ventional building, and the office areas are not conditioned by conventional HVAC systems. Rainwater is used for flushing toilets, and a sophisticated sanitation system was installed with urine-separating NoMix toilets.⁸⁹

Designed by Bob Gysin + Partner (BGP Architects), the interior of Forum Chriesbach is organized into various functional zones, grouped around a full-height atrium. Cantilevered conference pods hover over

the atrium. The main 2mwide staircase and transparent wall parti -tions link the building together and turn the atrium into a spatially expansive experience.⁹⁰

“We laid out the interior spaces around a large, five-story atrium which functions as a village square where presentations, exhibits and events can be held,” said Gysin. “This community space is open, flanked at each floor by glass parapet walls. In fact, a great many partitions throughout the building are in glass, which gives the interior its great transparency. So from the lobby you can see into the offices and meeting rooms, practically through the whole building. Orienta -tion in the lobby is instant; you understand the building immediately.

You can see the stairs leading to the corridors, leading to the offices around three sides of every floor. You can see who is there and who is not, who is in a meeting room, who is talking together in the corrid -ors. And the corridors are three times as wide as normal corridors—

we conceived them as places for communicating. Spontaneous, informal conversations are vital to the activities that go on in this building. The researchers like their informal meetings, and they feel com fortable in the building.”⁹¹

In addition to providing office space for 150 employees, the floor plan includes a lecture hall for 140 people, seminar rooms, meeting rooms, contact areas on four floors with desks and seating areas, a joint library, and a staff café. “Researchers don’t like to work in open-plan offices, so we gave them small offices for a maximum of four people,” said Gysin.⁹²Instead, the corridors between the atrium and offices are designed to be collaborative spaces with seating for spontaneous meetings.

The building interior is designed for flexible room configurations.

“The term ‘sustainability’ has become a bit of a vogue word in recent years. But if you consider it seriously, it would mean that things we make quickly might not necessarily be the best in the long run,” said Gysin. “A sustainable building is surely one that serves its purpose for a long time. In this age, in which no building type remains unchanged over the centuries, architecture should possess flexibility. Materials that are appropriate for a building designed to last a century are different from those for a building design to last only 20 years. But in either case, the materials must be suitable for recycling, or even better, up-cycling.”⁹³

The architectural scheme is based on the principle of “saving 7.68 Right: The 92,000-sq-ft Eawag Forum Chriesbach in Dübendorf uses 75 percent of the energy of a typical office building.

Photo: Eawag – aquatic research.

energy rather than paying to generate it” and resulted in a low-energy building.⁹⁴The sustainability strategy consists of three primary systems that are highly integrated and serve multiple functions:

• A multi-layered, super-insulated, light-modulating building envelope that incorporates emergency egress externally.

• A highly efficient HVAC system that relies on multiple passive energy sources.

• A full-height atrium that unites interior spaces, transmits daylight, and helps control the indoor climate.⁹⁵

One of the goals of the project was to align with the vision of the 2,000-Watt Society, an initiative of the Swiss Federal Institute of Technology. The initiative advocates the reduction of each person’s consumption to 2,000 watts, or 17,520 kWh annually.⁹⁶According to the 2,000-watt program, energy consumption in office buildings should be limited to 600 watts per capita, or 5,256 kWh per person per year.⁹⁷

Envelope

The box-like shape of the building may be traditional but the shimmering aqua façade is not. The appearance of the façade changes with the weather, time of day, and season. Composed of 1,232 blue glass louvers, the façade is a visual reference to the main concern of the institute—water—but is also a major contributor to the building’s

performance. Each of the glass panels is 9 ft 3 in (2.8 m) high, 3 ft 4 in (1 m) wide and nearly an inch (24 mm) thick. Each is laminated from two sheets of glass, one of which is light blue with a transparent dot-screen (frit) pattern. Considering Dübendorf’s climate, the team tested varying shades of blue and sizes of frits to find an ideal amount of transparency for both daylighting and thermal gain.⁹⁸

The active louvers surround the building like a second skin and adjust automatically to optimize temperature and lighting conditions while minimizing energy use. In synchrony, the motor-driven louvers rotate on a vertical axis in five-degree increments following the daily movement of the sun based on data from the building’s weather station. In the winter, the louvers usually remain parallel to the sun’s rays to allow for maximum solar gain. In the summer, panels angle to block direct sunlight while allowing daylight to penetrate the building.⁹⁹

Atrium

The interior is divided into two climate zones: the comfort zone and buffer zone. Comprising offices, meeting rooms, and other work areas, the comfort zone is mechanically ventilated, with the tempera -ture actively maintained at a comfortable level. The buffer zone, comprising the atrium as well as the adjacent corridors on each floor, has no permanent ventilation or direct temperature control. The design allows for greater fluctuation in temperature in the buffer zones.

To allow this, the zones are separated by insulated glass partitions.¹⁰⁰

In winter, the building uses energy to heat the offices and other permanently used rooms, but not the circulation spaces in the buffer zone. The atrium is not only warmed by the sun but via the well-insulated comfort zone that surrounds it on three sides. It maintains a comfortable temperature year-round with almost no added energy.¹⁰¹According to a detailed study of the building, “the atrium plays decisive role in determining the temperature regime of the whole building.”¹⁰²

In summer, the building is cooled using night-flush ventilation. The atrium windows open to flush out the warm air and provide cross-ventilation. Motorized windows on both sides of workspaces—the exterior windows and corridor partitions—open to allow warm air to exit via the atrium and outside cool air to enter the offices. The incom -ing air cools the thermal mass (the interior concrete floors), which provides cooling throughout the day. The only energy used in the cooling process is the weather station, the control system, and the motorized windows.¹⁰³

HVAC

With the exception of the ground floor (café, library, and reception area) the building is not mechanically heated with a typical (Swiss) hydronic radiant system. External (solar, geothermal) gains and internal loads (people, lighting, computers, and other equipment) generate enough heat to maintain a pleasant ambient temperature.¹⁰⁴

A forced-air system uses geothermal, solar, and recovered energy to provide supplemental heating and cooling. A series of seventy-eight plastic ducts draw fresh air into the earth where it is preheated in winter.

The air is then directed through the server room to pick up additional heat while cooling the computers. A heat exchanger extracts the heat, and the warm fresh air is distributed to the rooms within the comfort zone via insulated ceiling ducts. If additional heat is required, a 3,170-gallon (12,000 liter) thermal storage tank captures heat from the kitchen appliances and rooftop solar vacuum-tube collectors (which also supply service hot water).¹⁰⁵

The PV installation on the roof provides 70,000 kWh of electricity annually, about one-third of the building’s energy consumption (not including the computer servers). The solar thermal installation produces about 25,000 kWh annually, equal to the site’s heating demand from the local area heating network.¹⁰⁶

With a measured primary (source) energy demand of 98 kWh/sq m/year, the building is significantly below the required Swiss federal Minergie-P standard of 141 kWh/sq m/year.¹⁰⁷Developed in 2001, Minergie-P is a more stringent specification, based on the Passiv Haus concept that originated in Germany to designate ultra-low-energy buildings.¹⁰⁸

Water

Water is the main topic of research at Forum Chriesbach, and so of course the building incorporates an innovative water-management strategy. In fact, one building system is a component of current research. In addition to water-free urinals, the restrooms utilize NoMix toilets, which separate urine and feces. Urine is collected and drained into local storage tanks for research purposes. Men’s and women’s urine is even stored separately, to study the differences. Separate

7.69 Forum Chriesbach’s interior spaces surround a large, five-story atrium featuring artwork inspired by a water molecule.

Photo: © Eawag – aquatic research.

treatment of urine reduces loads on wastewater-treatment plants and makes solids treatment easier. Eawag scientists study practical uses for substances found in urine and test various urine-handling technologies for future widespread use.¹⁰⁹

Collecting and reusing rainwater on the roof of Forum Chriesbach reduces potable water demand. Captured water is used for toilet flushing. Potable water is only used for preparing meals in the staff café, filling the water fountains, and hand washing.¹¹⁰

Adjacent to the building, a rain garden stores rainwater harvested from the green roof. The garden is also a triple-chamber biological system that conditions the water for use in toilet flushing. Eawag researchers are also studying new processes for treatment and purification of rainwater.¹¹¹

Forum Chriesbach proves that a high-performing building is possible through innovative and progressive approaches using conventional materials and existing technologies. At a cost of 29.5 million Swiss francs (US$32 million¹¹², or $348/sq ft), similar to conventional Swiss offices of the same size, the building was also financially practical, especially considering the reduced operating costs.

Some may say that the architecture and technology at Forum Chriesbach tests the limits of what’s possible, but Gysin disagrees.

“Actually, there are no limits; at the most there are limit ranges. In geography, the transition from mountains to steppe to desert is fluid.

On my first trip to Italy when I was 16, I looked intently out the train window to notice the change between Switzerland and Italy, but everything looked exactly the same on both sides of the border. Limits are artificially defined. This room [we are in] might have clearly defined

limits, but as soon as we are outside this building, we talk about intermediate spaces and if we look up toward the heavens, space has no limits. We set our own limits ourselves.”¹¹³

TABLE 7.32

Annual energy and water use, 2007^a

Annual use (kWh) Intensity Primary Energy Intensity

with servers and solar

Heating from network 63,971 kWh 7.5 kWh/sq m 7.5 kWh/sq m

Space cooling from network (excl. servers) 124 0.0 0.0

Gas for kitchen/cooling from network 14,000 1.6 1.6

Domestic hot water and heat losses 32,700 3.8 3.8

Electricity (excl. servers) 266,000 31.2 71.4

Embodied energy (Grauenergie)^b —- 28.6

Server electricity (allocated to building) 43,000 5.1 11.5

Total site energy use 419,795 kWh 49.2 kWh/sq m 98 kWh/sq m

Add: solar thermal 26,439 3.1 3.1

Waste Heat Recovery 1.9

Net primary energy demand 103 kWh/sq m

Solar PV & thermal 23

Water use 1,300 kl 152 l/sq m

a B. Lehmann, et al., op.cit.

b Based on 37.6 average life-span of building components, B. Lehmann, Ibid.

At a glance

Name: Eawag Forum Chriesbach Location: Dübendorf, Switzerland Size: 91,850 sq ft (8,533 sq m) Completed: September 2006 Construction Cost: CHF 29.5 million Program: Office building

Vacuum-Tube Heat Pipe-Type Solar Collectors: 538sq ft (50 sq m)

PV Power Plant: 77 kWp

Project team

Owner: Eawag, Swiss Federal Institute of Aquatic Science and Technology and Empa, Materials Science and Technology Architect: Bob Gysin + Partner BGP

Energy and Mechanical Engineer: 3-Plan Haustechnik AG Architecture and Energy Engineer: EK Energiekonzepte AG Engineering and Design: Henauer Gugler AG

Electrical Engineer: Büchler + Partner AG

General Contractor: Implenia General Contracting Ltd.

DANIEL SWAROVSKI CORPORATION,