EPUD Revisited

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Emerald People's Utility District Revisited: A Post Occupancy Analysis of Thermal and Daylight Design Implementation

Authors: Architecture 407/507 class, Winter 1999

School: University of Oregon
Faculty Advisor: Professor Alison Kwok

Abstract:

The Emerald People’s Utility District, EPUD, is a publicly-owned utility interested in energy conservation and renewable sources for generation. Two architecture firms: Equinox Design, Inc. and Group Architects & Planners, in addition to a daylighting consultant from the University of Oregon, were brought together to collaborate on the design of EPUD’s new headquarters.

The building's design combines several energy conservation strategies such as the integration of daylight with electric light, passive cooling, and supplementary passive heating. A seminar class of graduates and undergraduates of the University of Oregon conducted an investigation of this building during winter term (10 weeks).

We focused on thermal comfort and daylighting. Our hypotheses stated that thermal comfort during the winter is sacrificed by the thermal mass strategies used in the building and that the daylight integrated electric lighting system functions as designed by evenly distributing the light and providing occupant satisfaction. To evaluate the building, the class divided into two teams: thermal comfort group and lighting group. Each group developed a set of inquiry questions.

The success of the building lies in having an group of informed occupants and an outstanding maintenance program. Workers know how the building operates and they have a fairly high degree of control over their thermal and luminous environment. The daylighting strategies in the building work well. There is an even level of illumination provided at the task level and people are satisfied with the general lighting conditions. The daylight-integrated lighting system did not perform as expected by stepping the electric lighting down when there is adequate light. Although people responded with comfortable thermal sensations and did not perceive the surfaces in their environment to be too cold, they were aided by heat from local space heaters. Recalculations of the effective thermal mass (using rule-of thumb) found that much more thermal mass was available than necessary, absorbing too much of the available heat (from equipment and any direct sun) making various locations become too cool.