Technical Design for Building Performance Knowledge Community

Premnath,

While at the AIA Research Corporation in the early to mid 1970's and then later at the Solar Energy Research Institute, we developed a whole-building, integrated energy design process to assist architects and engineers to understand ( define ) and to develop effective design solutions to energy design problems of specific building types. One aspect of this process was call "Energy Use/Cost Characterization" and was undertaken during the Programming Phase of the architectural design process.  In the E2ASE Design Process (Energy Efficient Architecture Sensitive to the Environment), what we called our energy and environmental design process at Architectural Energy Corporation, I defined Energy/Cost Characterization as follows:

"The purpose of energy use/cost characterization is to identify the energy problems and
opportunities in a way that facilitates the development of energy design solutions within
the economic criteria of the project. A set of building energy analysis simulation (such as
the DOE-2 program) runs are performed on the reference building model to characterize
the overall building energy consumption. The entire reference building is simulated to
establish a baseline in terms of energy consumption, demand, and cost. Next, each
component of overall building energy consumption, listed in Table 1, is eliminated from
the simulation, and the annual energy consumption, demand, and cost for each run is
calculated. The components having significant impact on overall energy consumption
will show a significant reduction in the annual energy cost when eliminated from the
simulation. This exercise identifies the important factors in overall building energy
consumption and points the design team to solutions that can make the greatest impact
on reducing energy consumption, demand, and operating costs.

Table 1: Elimination Parametrics (from Reference 1)
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Elimination Parametric Category Input Change
1. Illumination Lighting W/sf = 0
2. Occupants Number of people = 0
3. Equipment - plug loads Equipment power = 0
4. Ventilation Outside air = 0
5. All internal loads Combination of 1 through 4
6. Opaque envelope conduction R wall > 100
7. Glazing conduction Glazing U value = 0
8. Solar gain through glazing Glazing shading coefficient = 0
9. Infiltration Infiltration air = 0
10. All envelope loads Combination of 6 through 9
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Energy use/cost characterization also provides the necessary information to establish
energy performance goals relative to energy consumption, demand, and cost."

Through Energy Use/Cost Characterization, those design elements driving energy use / cost could be identified, but also a project specific energy performance target / goal could be established, and specified in the Program -- before any design work has begun. As importantly, this information was now integrated into the Architectural Program, and approved by the owner and the design team -- providing clear, objective criteria for developing and evaluating the proposed design solution.

Undertaking Energy Use/Cost Characterization is essential if the design team is to focus on design elements that significantly impact whole-building energy performance.

Michael J. Holtz, FAIA

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Michael Holtz FAIA
Boulder CO
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