Page 58 - Zero Net Energy Case Study Buildings-Volume 1

CASE STUDY NO. 3 IDeAs OFFICE BUILDING
IDeAs Office Building
Case Study No. 3
Data Summary
Building Type: Office
Location: San Jose, CA
Gross Floor Area: 6,557 gsf
Occupied: April 2007
Energy Modeling Software:
eQuest version 3.51
Modeled EUI (Site)
24.8 kBtu/gsf-year
Measured EUI (Site)
18.7 kBtu/gsf-year
On-Site Renewable Energy System Inatalled
30 kW (DC) Solar PV
Measured On-Site Energy Production
40,432 kWhr/year
21.9 kBtu/sf-year
Owner/Client
David and Stephania Kaneda
Design Team
Architect: EHDD Architecture, San Francisco CA
Structural Engineer: Tipping Mar, Berkeley CA
Mechanical / Plumbing Engi- neer: Rumsey Engineers (now part of Integral Design Group, Oakland CA)
Electrical Engineer and Light- ing Designer: Integrated Design Associates - IDeAs (now part of Integral Design Group, Oakland CA)
Landscape Architect: MPA De- sign, San Francisco CA
General Contractor
Hillhouse Construction
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This small commercial office building is one of the first measured and confirmed zero net energy buildings in the United States. Completed and occupied in 2007, the energy performance of the privately-owned 6,557 sq. ft. structure has been carefully documented, confirming that it has annually sent slightly more electrical energy back into the public utility grid over the course of the past five years than it has consumed. The design strategies, commissioning measures and post-occupancy adjustments made to some of the building systems describe a model approach applicable to similar building types in California.
Background
In 2005, David Kaneda and his firm, Integrated Design Associates—IDeAs (recently merged with Integral Group, Oakland, California), purchased a small tilt-up concrete building that had been built in the 1960’s in a suburban shopping center south of San Jose, California, to house a bank branch office. The plan was to renovate the structure extensively to house his staff of engineers specializing in electrical engineering and lighting design, but the vision was to transform the structure into a high performance green building in every aspect and to demonstrate that it was feasible technically and financially to build a zero-net-energy and zero-net-carbon building within existing constraints and using existing technologies.
The building is a renovation of an existing building. Because of the extent of the renovation work, it is best characterized as “deep retrofit.” Like every building project with a ZNE goal, as we now know, the process of its design necessarily involved full integration of all design disciplines in the early design phases, analyzing and evaluating every aspect that would affect the energy “bottom line.” In the case of this project, the contractor was selected early and was also involved throughout the process. Understanding the need for the early, integrated design decision-making and how it would make a ZNE performance possible within the typical constraints of this type of building is an important part of the achievement of this project.
Low-Energy Design Approach for the IDeAs Office Building
With the basic requirement that available on-site renewable energy balances the total building energy load over the course of a year, the approach taken with this project was to simultaneously determine how low the load could reasonably be set with “a reasonable cost premium” and how much renewable on-site energy could be realistically harvested. The encouraging result of this quick study was that there would be enough renewable energy available through a standard ap- plication of solar photovoltaic panels on the roof and an added canopy to satisfy an achievable annual energy demand of approximately 20,000 Btu/sf-year.
This target energy budget set the parameters for the design and specification of the different buildingcomponentsthataffectedthetotalenergyuse.Thefollowingisadescriptionofeachof these component features and systems.
Building Planning and Building Envelope
Given the large open space desired for the engineering staff workstations within the small of- fice building, the plan concept is simple: place the open workstation along the south side of the building where a new large glazed area of sliding doors and windows are located and individual offices and conference space along the north side with no exterior windows but a shared open view toward the south.
Many alterations were done to the basic building envelope, including the addition of daylight-pro- viding skylights, high performance windows and added insulation. The skylights were distributed
Zero Net Energy Case Study Buildings: Volume 1