REAL-WORLD EXAMPLES

Three real-world examples of high-performance buildings exemplify whole-building high performance.

Mapleleaf Orthopedics

The Mapleleaf Orthopedics building in Pueblo, Colo., is southern Colorado's first LEED-certified building and has made a statement in the local building and design community. The 8,000-sq-ft building is oriented along an east-west axis to better harness the sun's heat energy. Renewable-energy and energy-efficiency features dramatically decrease the building's carbon footprint.

A 30.6-kw photovoltaic (PV) system meets nearly 90 percent of the all-electric building's energy needs. The owner requested that the PV panels be a highly visible and dramatic part of the building's architecture. The PV system is connected directly to the utility power grid, and any excess generated energy is fed back into the grid. Essentially, the utility grid operates as a battery, storing excess energy. This building is an example of how renewable energy can be incorporated easily into a building's design.

Windows are located throughout the building to provide daylight and views for more than 90 percent of all of the occupied spaces. Shading techniques are used to block direct sunlight during summer. Daylight harvesting and occupancy-based lighting controls are used to further reduce expended lighting energy to roughly 0.8 w per square foot.

Heating and cooling are provided via ground-source heat pumps with field-verified heating efficiency of 350 percent (a coefficient of performance of 3.5) and an energy-efficiency ratio of 19. An energy-recovery ventilation air-handling unit tempers outdoor air and reduces ventilation load by 75 percent. Twenty air exchanges per hour improve indoor-air quality. Low- and no-volatile-organic-compound (VOC) paints, glues, stains, and flooring add to the quality of the indoor environment. Other notable high-performance features include low-flow water fixtures and landscaping, pervious paving, sustainable lumber, recycled-content product, and wheat-board casework.

All of this results in a building that performs at 19 kBtu per square foot per year, nearly 80-percent lower than a typical building. Builders can learn how incorporating renewable, sustainable concepts in their own designs can be easy and cost-effective for the owner and healthy for occupants.

Namaste Solar Electric

Namaste Solar Electric remodeled a 15,000-sq-ft warehouse for its new offices in Boulder, Colo. The company, which manufactures and installs PV systems, has submitted the project for LEED for Commercial Interiors Gold certification. The building benefits from daylighting, recycled building materials, increased insulation, evaporative cooling, and environmentally friendly finishes.

The building's electricity is provided by a 10-kw solar system. The PV panels are located on the rooftop, as well as a solar awning. The project's insulation consists of a combination of fiberglass batt, spray foam, and wet-blown cellulose.

The building's HVAC system provides heat via a central high-efficiency, gas-fired hot-water boiler serving baseboard convectors with individual zone control. Cooling is provided via zoned direct-evaporative-cooling systems for all areas except the conference room, which is served by an Energy Star-rated packaged rooftop heating and cooling system. A dedicated outdoor-air system provides tempered ventilation air during the heating season.

The project also reused existing materials. Salvaged-wood framing was used to frame interior and exterior walls and create exposed flat-stacked low partitions.

Eco-finishes and fixtures, such as zero-VOC paints and carpet, a polished concrete slab, recycled-content ceramic tile, carpet and toilet partitions, eco-friendly furniture systems, and waterless urinals, dual-flush toilets, and low-flow faucets, were chosen to reduce toxicity and conserve resources. The project garnered $29,086 in efficiency rebates from the flexible-rebate division of the city's business-incentive program.

Hyland Village Community Center

Designed to be the first zero-energy community center in Colorado, Hyland Village Community Center is under construction and will include meeting rooms, a small kitchenette, restrooms, and an associated outdoor seasonal pool. Zero-energy buildings use the equivalent of the energy provided by on-site renewable sources.

The project will harness passive solar energy through south-facing windows and a Trombe wall. The Trombe wall will collect and store solar energy in a concrete-mass wall during the day and release energy to help heat the building at night. All of the facility's electric needs are fulfilled via 14.5 kw of PV panels. Solar-thermal panels are employed to handle domestic water and space and pool heating.

The center's insulated building shell will require little cooling, which will be provided by a fan that will flush the building with cool air at night. Other notable features include a greywater system for shower-water reuse in toilets, air-to-air heat recovery on ventilation air, low-flow plumbing fixtures, and a live green roof. The project has been submitted for LEED Platinum certification.

PROMISING HVAC TECHNOLOGIES

Data from Arthur D. Little, an international management-consulting firm, estimates that roughly 59 billion sq ft of commercial floor space in the United States consumed 14.7 quads of energy in 1995. HVAC systems consumed 4.5 quads of this total, representing the largest percentage of energy end-use. In July 2002, the DOE published a report, “Energy Consumption Characteristics of Commercial Building HVAC Systems, Volume III: Energy Savings Potential,” in which 55 technology options were analyzed for energy-savings potential. The 15 most attractive options were given a more refined analysis (Table 1).

Figure 1 presents the simple payback of 11 of these options. Radiant-cooling and dedicated outdoor-air systems have an instantaneous payback requiring no additional capital outlays.

Several areas absent from the DOE's list of 15 promising technology options include cogeneration/waste-heat utilization opportunities, building-envelope technologies that reduce building heating/cooling loads, renewable energy, and natural-cooling/ventilation technologies. As previously mentioned, these technologies often are present in high-performance buildings.

CONCLUSION

There is no single path to a high-performance building, although enhanced collaboration and team commitment to goal success is paramount. Delivering a high-performance building on time and within budget is a top priority. Experience is a valuable commodity in teams designing a high-performance project. Measurable goals should be established early and accomplished throughout the duration of a project. Modeling should be used to inform the design, commission the project, and monitor post-occupancy. These steps will ensure a high-performance project has the greatest chance for success.

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Peter C. D'Antonio, PE, CEM, LEED AP, is the director of business development at PCD Engineering Services Inc., an award-winning provider of mechanical/electrical engineering, commissioning, and energy analyses for buildings. His work has been recognized with design and service awards from various organizations, including the U.S. Green Building Council, Colorado Governor's Energy Office, and American Solar Energy Society. He can be reached at peter@pcdengineering.com.

Resources for More Information

Resources for additional information on high-performance-building mechanical-system design include:

• “Advanced Energy Design Guides,” which can be found at www.ashrae.org/technology/page/938.

• “Los Alamos Sustainable Design Guide,” which can be found at www.eere.energy.gov/buildings/highperformance/lanl_sustainable_guide.html.

• “High Performance HVAC,” which can be found at www.wbdg.org/resources/hvac.php?r=dd_hvaceng.

• “Energy Design Guidelines for High Performance Schools,” which can be found at www.eere.energy.gov/buildings/highperformance/design_guidelines.html.

• “High Performance HVAC,” which can be found at www.highperformancehvac.com.

• “IAQ Design Tools for Schools,” which can be found at www.epa.gov/iaq/schooldesign/hvac.html.

• “Building Energy Software Tools Directory,” which can be found at apps1.eere.energy.gov/buildings/tools_directory/subjects_sub.cfm.

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