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The Smithsonian Institution created a research campus on Colon Island in Bocas del Toro, Panama, located off the Caribbean coast on a sensitive site next to a mangrove swamp. Known as the Smithsonian Tropical Research Institute (STRI), the design for its large “green” laboratory building is based on "net zero impact" -- collecting its own water, treating its own waste, and generating its own energy. The form of the building itself is responsive to its site and was designed for energy efficiency. Interior volumes are shaded by the large photovoltaic roof, which minimizes direct heat gains. The narrow plan, together with the space between the two roofs, allows cross ventilation to keep the building cool while providing daylight and views. The translucent lower roof, along with the partially transparent photovoltaic roof, admits an optimum five percent of daylight into the interior rooms for daylighting. The 38-kW photovoltaic upper roof produces approximately 75 percent of the building's energy needs, while doubling as the rainwater collector. Raising the entire building on concrete piers helps to catch prevailing breezes for passive cooling, and also provides flood protection and minimizes the lab's impact on the site. Air conditioning is zoned so that individual rooms can be cooled separately. Materials were chosen for environmental reasons, and, where possible, were left without additional finish. Sustainably harvested local hardwood was used for the upper structure and siding of the building. The pond area, which had been filled with saw mill waste, was restored to provide habitat for local species. Six crocodiles now reside there. A constructed wetland treats blackwater and graywater waste from the laboratory, emptying into the pond. The rainwater system treats and uses all rainwater from the roof to be used as the main water supply of the building. Any overflow water from this system goes into the on-site pond. (Scroll to bottom for additional resources)
Bocas del Toro has a tropical climate, with consistently warm temperatures, high humidity, and abundant rainfall. Passive-solar concerns greatly shaped the building’s form, including the double roof and shallow, sloped, photovoltaic roof, which is optimal for electricity generation at this latitude (9° 20' 0" N). Nighttime light pollution is minimized by using low-level exterior path lighting. The lot size is 26,000 m2 with a building footprint of 30,800 sq ft (2,860 sq meters).
The STRI at Bocas del Toro is an education and research facility, providing scientists and students with access to an extraordinary diversity of marine and terrestrial biota. This station is situated among areas of undisturbed forest, a coastal lagoon system, and numerous islands and reefs. The green laboratory was designed to minimize its environmental impact while providing an exemplary scientific facility that is focused on both marine and terrestrial environments. The building's main functions — labs for resident and visiting scientists, teaching labs, a conference room, and support spaces — occupy a string of volumes on a raised platform shaded by an overhanging pitched roof.
The site had previously been home to a sawmill. The pond area, which had been filled with saw mill waste, was restored to provide habitat for local species. Bocas del Toro is a complex region of islands, mainland bays, rivers and forested mountain slopes on the Caribbean side of the Panamanian isthmus. The very high diversity of marine and terrestrial ecosystems makes Bocas an ideal area to study natural environments. However, Bocas is also a socio-politically complex setting—a site with fisheries, growing tourism, agriculture and a significant population of endangered sea turtles and manatees. It comprises a model region for working on the important issue of sustainable multiple uses. Bocas del Toro is a mosaic of cultures: Spanish, Indian, English-speaking and French-speaking West Indians, Germans and Americans were part of the development of the region. The architecture of the nearby town employs a wooden vernacular style, with large outdoor spaces and overhanging tin roofs.
Additionally, Bocas del Toro offers an ideal setting for conducting paleoecological studies to answer important questions about the history of the Isthmus of Panama. The rocks and fossils around Bocas hold the key to understanding when and where the Isthmus began rising, and when and where it closed, separating the Atlantic and Pacific Oceans. Pinpointing the time sequence of this division, which triggered the formation of the Gulf Stream, among other major natural events, has huge ramifications across varying fields of scientific inquiry as diverse as evolutionary biology and climatology.
The majority of the building's users are visiting scientists who stay either on-site in the dormitories or in the village of Bocas del Toro. Many of these off-site visitors use a bicycle, taxi, or local bus to get to the site. The amount of parking provided on-site accommodates approximately eight cars.
In an area with abundant rainfall and a non-potable municipal supply, the decision to collect rainwater was an easy one. The form of the roof directs rainfall into centrally located tanks on the lower level, where it is stored in 4,000-gallon storage containers, filtered, and treated with ultraviolet light before being used as the building’s water supply. Since the site is already hooked up to the municipal water supply, emergency back-up is easily provided. Fixtures are of the lowest water consumption locally available. Potable water is supplied via bottled-water coolers. No water is used for landscaping purposes.
STRI is currently designing a constructed wetland, to include the existing on-site pond, to treat both greywater and blackwater from the facility. The laboratory is a marine research field station, and STRI does not allow hazardous chemicals to be used in the laboratories since they would be difficult or impossible to treat in the wetland. Currently, waste is treated with a conventional on-site septic system.
Extensive research was done to find the most suitable type of wood for the upper frame and siding. The wood chosen, canafistula, is naturally resistant to termites and fungi. FSC-certified wood is not produced in Panama, but the Panamanian environmental agency, ANAM, has its own sustainable forestry regulations, and the wood used was locally harvested and certified by ANAM. The same hardwood was used for windows, doors, exterior siding, and siding in the lobby.
The building foundation required a reinforced concrete mat because the bearing capacity of the soil was extremely low. The site is also often waterlogged, and the concrete lower level helps minimize termite and fungi damage to the upper wood structure.
Wherever possible, the structure became the finish, and there are minimal other finishes; interior walls are water resistant gypsum wallboard, and the lower roof is translucent fiberglass. Specified paints are low-VOC, and the interior floor finish is ceramic tile.
All working spaces have translucent, daylit ceilings and are within five meters of a window, affording good views and daylighting. Individual occupants in all spaces have the choice of air conditioning, ceiling fans, or natural ventilation from operable windows.
Daylighting of five percent comes through the semi-transparent fiberglass lower roof. Since the exterior areas are shaded, users' eyes have time to adjust to the lower interior light levels, and typically will not immediately turn the lights on before their eyes have time to adjust.
The air conditioning system was designed to lower relative humidity to 35-65 percent, while providing an internal temperature of 75°F ± 4°F. Ceiling fans are provided in each room to allow occupants to be comfortable at higher temperatures. The air-conditioning units are zoned to adjust to use patterns. A separate fresh-air heat-pump supercools the air to reduce humidity before supplying makeup air to the labs.
Low-VOC paints were used throughout, and wood that did not need to be treated was chosen. Detailing of water runoff, along with good ventilation of all spaces, was designed to avoid conditions favorable to mildew growth.
The form of the building was heavily guided by passive-solar concerns. The double roof shades interior volumes, hence reducing solar heat gain. The building-integrated photovoltaic (BIPV) roof faces south and has a shallow pitch, an optimal position for maximum electricity generation at this latitude. Measurements indicate that the photovoltaic system provides up to 30 kW of actual instantaneous output and a yearly total of close to 70,000 kWh. The BIPV roof supplies approximately 75 percent of the base building energy use of the facility. Because the grid power on the island is diesel-generated -- a very dirty and unreliable source of power (compared to the average U.S. grid supply) -- the benefits of the BIPV system are significantly greater than they would be in the mainland U.S.
Efficient lighting strategies include 100 percent daylighting during daylight hours and the exclusive use of fluorescent light bulbs at other times.
All parts of the building could operate during a blackout. The unreliability of local grid power was a major impetus behind the design. There is daylight in every room, and the main photovoltaic system has been configured so that, after it turns off for a few seconds, when the main power goes off, it quickly turns on again when the on-site generator comes on. A secondary PV-UPS subsystem dedicates 6 kW PV to a 16-kWh battery bank serving one or two outlets in each lab for sensitive electronic equipment. Another bonus is that on-site photovoltaic generation provides the most electricity at similar times to peak air-conditioning loads.
Bocas del Toro is an island off the Caribbean coast of northern Panama, located at 9°N latitude, 82°W longitude. The climate is tropical, with an average relative humidity of 80-85 percent, and an average temperature of 26-32°C. Diurnal temperature difference is minimal. Average monthly rainfall varies from 160 to 450 mm. The basic strategy was to maximize airflow and minimize solar heat gain. The form of the building developed out of passive solar concerns. The double roof, which has an overhang large enough to prevent the sun from hitting the exterior walls, shades the interior volumes. This substantially lowers solar heat gain, and ventilation of the large space between the two roofs (with louvers at the apex of the roof) prevents the build-up of hot air. The narrow plan and operable windows allow for cross ventilation and scenic views. The translucent lower roof, together with the partially transparent photovoltaic roof, allows an optimum 5 percent of daylight into the interior rooms for daylighting. The building design borrows from the local vernacular in its use of concrete piers to raise the structure, wood framing and siding for upper floors, and large overhanging roofs.
The learn more about the projects at Smithsonian's Tropical Research Institute in Bocas Del Toro, Panama, see the YouTube channel.