Demonstrating a Sustainable Path

by Alex WilsonMerrill Center Front final

The Philip Merrill Environmental Center of the Chesapeake Bay Foundation serves as a model of sustainable development and a demonstration project for resource protection/ restoration, environmental advocacy and education.

The Chesapeake Bay in Maryland and Virginia is the nation’s largest, most diverse and most productive estuary. More that 3600 species of plants and animals call it home, and more than a million waterfowl winter there. Thousands of “watermen” make their livelihood from the Bay’s bounty, which includes oysters, striped bass and more than a third of the nation’s blue crab. Many more make their living on the tourism spawned by the region’s rich natural and cultural history. The Bay is 200 miles long with nearly 12,000 miles of shoreline, and it drains 64,000 square miles of land including parts of New York, Pennsylvania, West Virginia, Delaware, the District of Columbia, Maryland and Virginia.

The ecological and economic importance of the Chesapeake Bay is tremendous, yet dramatic pollution and development pressures over the past 50 years have taken a heavy toll. Oyster harvests plummeted from 35 million pounds a year in the 1950s to less than 3 million pounds a year today. A prime culprit has been nutrient pollution, and while significant progress has been made, nutrients from fertilizer runoff, stormwater pollution and septic systems remain a significant problem.

So too is sprawl. The population of the Chesapeake Bay watershed is 16 million people – nearly 40% more than in 1970. Loss of wetlands, increased automobile use, agricultural runoff, deforestation and overfishing are just a few of the problems facing the Bay.

Since the 1960s, dozens of federal and state agencies, government commissions, academic programs, and nonprofits have been working to rescue the Bay from these problems and restore it to the healthy ecosystem it once was. The Chesapeake Bay Foundation (CBF), founded in 1967, has been leading the charge. Facing the need for more space in the mid-1990s, CBF trustees considered expanding in downtown Anapolis, Maryland, where they were based, but they couldn’t find the right building. Then they were approached about protecting a 31-acre property on the Bay that was slated for development. Could they protect the land by building on it?

From Vision to Reality
CBF purchased the land and hired SmithGroup, Inc., an architecture firm in Washington DC., to design a headquarters building that would be in keeping with the organization’s mission of resource protection/restoration, environmental advocacy and education. Because the site is located on the Bay, it was clear from the start this needed to be the greenest of buildings. Clearly, the use and management of water and protection of the land would be very high priorities, but so would low energy use, reliance on renewable energy sources and selection of materials that don’t result in significant environmental burdens during their manufacture.

With a $7.5 million gift from newspaper publisher Philip Merrill, the Foundation had the freedom to incorporate a wide range of leading edge green technologies, even those that increased construction costs. A decision was made to seek the highest level of LEED certification
. A visioning charrette, organized by the Sustainable Buildings Energy Council with support from the US Department of Energy, identified a wide range of strategies for greening the project. Those ideas were refined by the Smith Group and the Philip Merrill Environmental Center was completed in December 2000.

In serving as a model for sustainability, the building has succeeded admirably, and in 2000 it was awarded the first-ever LEED version 1.0 Platinum rating (the very highest). The building also received recognition from the AIA (American Institute of Architects) Committee on the Environment as one of the Top Ten Green Projects in 2001 and in the same year won an ASHRAE Technology Award.

The Greening of a Building
For starters, construction of the building had minimal impact on the 31-acre site. Only those portions of the property that had previously been developed were affected by construction – the 31,200 square foot building occupies roughly the same footprint as the beachhouse and swimming pool it replaced. The need for excavation was minimized by placing the building on piers, which also allowed parking underneath, thereby downsizing the parking area required around the building. Parking needs – and the environmental impacts of commuting by single-occupancy vehicles are also kept in check through CBF efforts to promote other means of transportation including carpooling, bicycling, walking, even kayaking by the building’s 100 employees. Alternative fuel vehicles (electric, hybrid, natural gas) are available for day use by employees who don’t drive to work.

Undeveloped portions of the site are being restored to the native ecosystems appropriate to the Bay shoreline. With a little help from human stewards, native grasses and wetland plants are quickly establishing themselves on the site, as are oysters in reefs just offshore.

Merrill Center Interior FinalThe overall building geometry is simple – basically a large rectangular box with a shed roof for the main building. A conference center on the south side is separate from the main building, allowing either building to be shut down when not in use, saving energy. The shed roof with galvanized steel roofing allows easy and effective collection of rainwater. The south facade is mostly glazed, with an exterior sun shade system to minimize solar heat gain during the cooling season. In addition to supporting the shade structure, an exterior timber frame on the south side also supports a PV array, although the timber structure results in some shading of the PV panels. On the interior, an open floor plan provides superb daylight distribution, significantly reducing the need for electric lights.

The building was designed to use very little energy. Structural insulated panels (SIPs) with four to eight inches of expanded polystyrene, provide insulating values of R-24 in the walls and R-30 in the ceilings. The fllors are insulated to R-20. Window glazings have a fairly low U-factor of 0.32 and a solar heat gain coefficient of 0.49, which is considerably higher than a typical office building. The solar gain provides passive solar heating as well as daylighting.

Renewable energy sources account for about 13% of the overall energy load. Flat-plate solar collectors provide 100% of water heating (saving as much as 120 kWh [kilowatt-hours] of electricity per day), and a 4-kW PV system offsets a small portion of the electric load.

Heating and cooling are provided with a ground-source heat pump system. Vertical wells were drilled for this system to minimize land disturbance and erosion that would have occurred with horizontal pipes. 48 wells, 300 feet deep were installed. An energy recovery wheel with desiccant dehumidification on the heat pump’s ventilation system also saves energy. Natural ventilation supplements mechanical ventilation when outdoor climate conditions permit. All this is controlled by a sophisticated energy management system, which even indicates to employees when it makes sense to open windows for natural ventilation.

Efficient and careful water management is a hallmark of the Center. A combination of conservation strategies reduced consumption by 90%, compared with a typical office building. Measured con
sumption is 58,000 gallons a year – about half a typical home. These strategies include composting toilets (used exclusively), water-conserving faucets, showerheads, laundry, sinks, and minimal irrigation needs for the native vegetation outside.

The rainwater catchment system satisfies most of the non-potable water needs and provides a reservoir for fire suppression. Rinawater passes through sand filters and is stored in cisterns made from pickle barrels salvaged from an abandoned pickle factory in the region. During the first year, rainwater provided 38,000 gallons of water. Potable water comes from a well on the property.

Stormwater is managed carefully too. Runoff from the parking lot is channeled into “bioretention” swales that use carefully selected soils, filtration media and wetland plants to remove pollutants from stormwater before it is channeled into the ground or, in the event of a large storm, flow into Black Walnut Creek and the Bay.

Finally, green building materials were carefully selected. Most of the building products were produced within 300 miles of the site. A few of the more innovative products include bamboo, cork and natural linoleum flooring, shade louvers made from salvaged lumber, metal siding and roofing with high recycled content and formaldehyde-free fiberboard trim and casework on the interior. Concrete salvaged from the previous building on the site was crushed and used for the road beds. The exterior timber framework is constructed of parallel-strand lumber, which is made from small diameter trees (one concern some have expressed is how those exposed timbers will hold up over time.)

Building Performance
Overall energy use, measured from August 2001 through July 2002 by the National Renewable Energy Lab shows a 19% savings compared with a similar building designed to meet ASHRAE 90.1 (2001). Energy savings of 28% are achieved with lighting and 29% with equipment for heating, cooling and ventilation. Savings with energy costs are even greater (27% total energy and 35% for lighting and equipment), reflecting the higher value of saved electricity. On a per-square-foot basis, the total annual measure energy use is 37,000 Btu/ft, and the annual energy cost is $1.07/ft (squared).

The PV system generates about 2700 kWh per year, and the solar thermal water heating system reduces water heating energy consumption by an estimated 41,000 kWh per year. The PV system output is only 42% of the predicted output, due largely to shading by the timber frame structure on the south side of the building.


The Chesapeake Bay Foundation
Smith Group
High Performance Buildings database

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Reprinted from Solar Today, a Content Partner.

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