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The Chesapeake Bay Foundation (CBF) headquarters, also known as the Philip Merrill Environmental Center, was designed in 1997. Back then, green building was a new idea that presented challenges in acquiring environmentally-friendly materials. But the Foundation persevered. The Center, which opened in 2001, is still one of the world’s most energy-efficient buildings, incorporating natural elements into a fully functional workplace which has minimal impact on its Bay- and creek-front surroundings. This sustainable structure was important to the mission of the CBF. The Chesapeake Bay Foundation is an independent non-profit organization dedicated solely to restoring and protecting the Chesapeake Bay and its tributary rivers. Since its founding 40 years ago, its goal has been to improve water quality by reducing pollution (“Save the Bay” is its motto!). The land that drains into the Chesapeake Bay covers 64,000 square miles, in a vast mosaic of cities, suburbs, farmlands, forests, and wetlands that extends across six states and the District of Columbia. Using photovoltaics, rainwater collection, composting toilets and a host of other measures, the building is cost effective and operates in harmony with the land, natural resources, and the Chesapeake Bay, proving that "green" buildings work. Clad in galvanized siding made from cans, cars and other recycled metal objects, the building was designed to use 10 percent of the potable water and 30 percent of the energy of the typical office building. Passive-solar principles and outdoor-air ventilation slash annual lighting and HVAC needs. Natural resources are harvested daily, including rainwater, solar energy, and the earth's constant ground temperature. The site has fewer parking spaces than usual, as the client's transportation management strategy meant more commuting by foot and bike - and boat.
by Anne Riley, Baltimore Daily Record, 15 Sep 2008 -- On the roof, photovoltaic panels convert the sun's rays into electricity. Inside, waterless toilets turn human waste into usable compost. And 300 feet below the surface, geothermal wells use the Earth's constant temperature for sustainable heating and cooling.
The building of the future? Hardly.
The Chesapeake Bay Foundation's Philip Merrill Environmental Center was designed more than 10 years ago (1997).
But despite its age, the building -- the first in the world to earn the U.S. Green Building Council's platinum rating on its Leadership in Energy and Environmental Design (LEED) scale -- is still hailed as a model of sustainability.
"It continues to hold up today," said Greg Mella of the Washington, D.C.-based design firm SmithGroup, which served as architect and engineer during the building's construction.
"Of all the buildings I've worked on since then, it's probably still one of the best examples of how passive design and integrated design contribute to a pretty sophisticated building," he said. "Everywhere you look in that project, from the closets to the lobby, you can really see a lot of those very straightforward sustainable strategies."
When the center was designed in 1997, green building was still a new concept, Mella said, making for an uphill battle as the foundation sought to acquire environmentally friendly materials.
"There were numerous challenges because really, there hadn't been any kind of commercial office buildings that were really that green," Mella said. "The foundation had these pretty lofty goals -- they wanted a fairly large-scale project that really addressed all of these things from water pollution to air quality to habitat protection."
"There weren't a whole lot of green building materials or contractors who were familiar with designing those green systems," he added. "It was before anyone really knew LEED, before it was kind of a household name."
LEED wasn't launched by the USGBC until August 1998. Although the Bay foundation had been planning to incorporate green building practices before LEED came into the picture, having the LEED scale as a model helped identify specific goals for construction, said Mary Tod Winchester, vice president of administration and operations at the foundation
"When you think about green, you can go off in all directions, and LEED provided the road map to stay focused," Winchester said. "We'd been practicing and encouraging green principles for 20 years. This was an opportunity to look at it holistically."
According to Winchester, building the world's first platinum- rated building was an important way for the group to confirm its commitment to the environment.
"The Chesapeake Bay Foundation has always tried to be a leader on environmental issues," she said.
"By being the first, we were able to convince so many business leaders, so many government leaders that it's something anyone is able to do.
"And having a facility like this on the East Coast has really helped push the movement."
The Merrill Center, paid for by a donation from newspaper and magazine publisher Philip Merrill, a foundation board member, cost $7.2 million, or $197 per square foot. That compared to an average cost of about $150 per square foot to build a non-green office building, Winchester said. Green materials were more expensive in the late '90s, she explained, because the marketplace had yet to be transformed by the green building movement.
"Economically, now it makes sense, even though it cost us a premium," she said.
Despite the center's expensive price tag, she said in some ways the building has paid for itself since it was occupied in 2000. For example, its solar-powered hot water heaters paid for themselves in 18 months, while the geothermal wells had a payback period of a little more than five years.
"What we ask people to think about is not just the cost savings but the savings on the environment. The paybacks are more than in dollars," she said.
About 8,000 people tour the building each year. Winchester said the visitors include school children, contractors and people simply interested in sustainable building.
"A lot of the contractors who want to be green don't know how to put it all together. Here, they can see what it looks like," she said.
Some of the design principles incorporated into the building were included for the sole purpose of educating potential tour groups, Winchester said.
"As a nonprofit, we have no need for hardwood floors, but we wanted to show people you can have a beautiful floor and still be green," she said, noting that the hardwood floors in the building are made from rapidly renewable bamboo.
"We wanted people to walk in and go, 'I could do that!'" she said.
"What we wanted was for any person, no matter what their background, to leave this building with one idea.
"We'd obviously like people to think holistically, but if everyone included one thing, imagine what the impact would be."
From the Smith Group:
In the years since the building's opening, monitoring of the energy and water consumption by the National Renewable Energy Laboratory has confirmed that the headquarters is meeting its environmental performance goals. A study conducted by the Center for the Built Environment at the University of California, Berkeley surveyed 25,000 occupants of 150 buildings to question users' satisfaction regarding air quality, comfort, acoustics and lighting. Of the 150 buildings rated, the Philip Merrill Environmental Center received the second highest overall satisfaction score.
From Mixed Mode CBE Berkeley Case Study:
Mixed Mode Strategy
Changeover system. Temperature and humidity sensors located on the exterior of the building determine when the climate is appropriate for natural ventilation. Upon sensing optimal conditions the building management system turns off the mechanical heating or cooling system and turns on modified exit lighting fixtures which notify the building occupants that it is ok to open the windows. Simultaneous to this change mechanical operators open the windows in the clerestory above the second floor to allow a natural draft to begin. Air is then pulled in though the operable windows, rises through the building, and exits through the clerestory.
Natural Ventilation Details
Operable windows on the north (leeward) side of the building are larger than those on the south (windward) side, to promote greater air velocities inside. Inlet windows total approximately 495 ft2, while outles total approximately 822 ft2. There are a combination of lower windows that can be operated by the occupants, and upper clerestory windows that automatically open.
HVAC System Details
Geothermal heat pumps with a desiccant dehumidification system are used for heating in the winter and cooling in the summer.
There are two ventilation fans in the east portion of the building to assist the natural ventilation flow in areas obstructed by the mechanical room and restrooms. The air enter enters on the east and is exhausted on the north. The fan sizes are 6500 cfm (1st floor) and 2800 cfm (2nd floor), providing an estimated supplementary air change rate 1.025 air changes per hour.
Configuration & Control
The building is arranged in an open plan office with the whole of the office space utilizing the mixed-mode strategy. A total energy management system monitors and controls energy use in the building. The system alerts employees when windows should be opened. Other windows are opened and closed automatically. The system also monitors daylight levels, adjusting electric lighting as needed.
There are approximately 60 individual controls for the windows. On the south façade, windows are banked together in groups of four. Hand cranks by Clearline are mounted on the first floor of the building. They operate both the lower windows and another set approximately 15 ft. high.
Rain sensors are located on the mechanically opened clerestory windows set to automatically close when wet weather arrives.
As of December 2001, the building setpoints were:
Nat’l Vent’ Available between 61-72°F.
Window use is up to discretion of occupants. Assist fans may or may not be turned on.
Assist Fans Off when indoor temperature < 68°F. On when indoor temperature > 72°F.
Summer Cooling Between 77-78°F.
Humidity is controlled to 50% with a 10% range.
Winter Cooling A/C or NV used when indoor temperature > 81°F. System turned off when indoor temperature < 78°F Humidifcation off when RH > 68%. Humidification turned on when RH < 50%.
Building Design Process Time Line
The U.S. Green Building Council's LEED Rating System was used in setting goals for the project before the design commenced. Benchmarking tours of other green projects and CBF's educational centers were influential in the design. A peer review of the concept design was organized by the Sustainable Building Industries Council (funded by the Department of Energy) and included reviewers from the Maryland Energy Administration, Maryland Department of Natural Resources, World Wildlife Fund and National Renewable Energy Laboratory. An integrated approach to design was used, and in-house engineers worked closely with architects. Air flow predictions made with simplified rules-of-thumb from ASHRAE Handbook of Fundamentals.
Designing Low-Energy Buildings with Energy-10 (DLEB/E-10) software was used for energy analysis. The initial design projection that the building would run in natural ventilation mode for 9% of the year was found to be actually 25% of the year after monitoring the building for several seasons.
Project commissioning was provided by SmithGroup, Inc. the designers of the building rather than an independent third-party, as Commissioning Agent. As a result, the contractor felt that the Commissioning Agent could not be a neutral arbiter. The mixed-mode component was one of the easier parts of the commissioning process. The architect credits this to the simplicity of the mixed mode system as compared to the daylighting and water collection/treatment systems which were more complicated and required changes and adjustments during commissioning.
The need to naturally move air from the first floor up to the second floor and exhaust through the roof when windows were open required special consideration due to required fire and smoke separations. To accommodate this, the architects worked with the fire Marshall to install a laser-beam detection alarm in the air slot connecting the two floors triggering the building fire response if smoke was detected moving through the building.
Other Design Issues
Due to a relatively low design fee available for the design of the building the architect wasn’t able to perform a full CFD study of the natural ventilation, a process they normally require to confirm intended design performance. Luckily, due to the excellent historical weather records collected at the nearby lighthouse, enough climate data was available to satisfy the designers that simple natural ventilation rules of thumb would result in a well-ventilated building.
Due to the relatively small building footprint on a 32-acre site, outdoor noise and air pollution are not a concern.
The University of California Berkeley Center for the Built Environment performed a web-based occupant indoor environmental quality (IEQ) survey at the Chesapeake Bay Foundation. The survey addressed general building satisfaction, general workspace satisfaction, office layout, office furnishings, thermal comfort, air quality, lighting, views, acoustic quality, cleanliness and maintenance, and several other functionality issues.
Occupants reported being satisfied or very satisfied with all categories but with more neutral comments in thermal comfort and acoustic quality. Thermally responses showed that occupants often find the building too cool in both warm and cool weather. This dissatisfaction was attributed to a lack of accessibility and control of thermostats as well as stratification of warm air to the upper floor and certain rooms that then result in discomfort. Acoustically the responses showed that the open plan cubicle workspaces were not providing enough privacy for occupants both between cubicles and between the open first and second floor.
• South-facing exposure.
• Takes advantage prevailing winds for natural ventilation.
• Minimizes heat island potential through landscaping and exterior material choices.
• Minimizes light pollution by using timers on exterior lights. Water Efficiency • Composting toilets.
• Water-efficient appliances.
• Native landscaping.
• Captures and reuses rainwater.
• Uses bioretention filter to treat oil and other pollutants in runoff from the pervious parking area.
• 90+% reduction in water use over an otherwise comparable conventional office building.
Energy and Atmosphere
• Maximizes daylight with large windows, clerestories, and an open interior design.
• Each workstation has a motion sensor that shuts off computer monitor and task lighting.
• Luminous sensors control overhead lighting.
• Photovoltaic panels on south wall.
• Solar hot water panels on the roof.
• South façade shaded with large slotted wooden structure, allows winter sun, keeps out summer sun.
• Interior blinds on west, south and east facades.
Materials and Resources
• Began with "cradle-to-cradle" philosophy (consider what materials can be made into at the end of their useful lives).
• Deconstruction, rather than demolition, of existing structures on the site; all materials were auctioned, salvaged, or recycled.
• Materials with recycled content (i.e., galvanized siding made from cans, cars, and guns; interior fabrics; and rubber flooring).
• Materials from rapidly renewable or regenerable resources (i.e., cork and bamboo flooring).
• Structurally Insulated Panels (SIPS) in roof and walls.
• Parallel strand timber beams.
• Local sources (over 50% of materials came from a 300-mile radius).
Indoor Environmental Quality
• Natural ventilation is used whenever possible.
• CO2 monitor and automatically controlled operable windows.
• VOC-free paints.
• Natural, non-toxic materials (i.e., cork, linoleum, bamboo).
Chesapeake Bay Foundation SIPs (72 kb)