Page 113 - Zero Net Energy Case Study Buildings-Volume 2

approach to the lighting design. During construction and before wall finishes were applied, how- ever, the client expressed concern about the light levels (despite the results of the daylight mod- eling and overall lighting level simulations) as well as the visibility of the space from the street through the large south-facing window. The concern was that the library might be misunderstood to be closed if the space were illuminated by daylight only. Other commercial enterprises along this busy street would have their electric lights turned on, indicating “open for business”, but the library would not.
The design team was directed to add suspended overhead electric light fixtures to the space even though the fixtures were not necessary for illumination purposes. Large, circular suspended LED fixtures were added to the space in response to this directive. The large space now basically has two electric lighting systems, each of which can separately provide the electric lighting necessary for backup of the daylighting skylight system—the distributed bookstack-mounted lights and the ceiling-suspended light fixtures. In addition, the visual effect is to reduce the perceived height of the space to the plane of the suspended light fixtures and obscure the appearance of the shaped ceiling designed to optimize the daylighting effect.
This issue was compounded by the fact that no dimming controls are currently operational. For the purposes of having the suspended light fixtures be indicators of “open for business”, the manual controls for these fixtures were locked in the on position. The measured energy use data indicates this high level of electric light energy being used.
There has been some effort to modify this operation and to revert to the original design intent of having all electric lighting under dimmable controls responding to the daylight sensors. However, the backup electric lighting systems, the distributed bookstack-mounted lights and the ceiling- suspended overhead lights, remain essentially redundant.
Post Occupancy: Occupant Behavior
Some of the interventions by building occupants are described above. The general design con- cept to separate the operation of passive systems from occupant control and make it automatic is best when these systems are integrated with the overall operation of the building systems. It is important for optimal results, however, to design as well the allowable options for user control of certain aspects of these systems. Not only is interference avoided, but the informed occupant can also make better use of these options to customize comfort conditions and often improve energy efficiency.
At the West Berkeley Branch Library, the library staff in particular did not initially understand the operational design of the building; they modified settings or used override switches as they would in a conventional building. A special meeting was arranged so that details of operation could be explained and how their user behaviors would result in lower energy use and a smaller carbon footprint for the building. The observed result of this effort to fully inform the staff seems to be a supportive attitude toward the target of accomplishing a ZNE performance for the building by the end of the year, which was indeed achieved, as well as smarter use of the building in general.
All of the case studies point to the advantages of a fully-informed and fully-supportive user group. For private clients and owners, this is an easier goal. Special efforts to provide information and training for public user groups seem to be required and should be planned as part of the transi- tion to the new space.
Zero Net Energy Case Study Buildings, Volume 2
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WEST BERKELEY BRANCH LIBRARY
CASE STUDY NO. 10