Page 112 - Zero Net Energy Case Study Buildings-Volume 2

CASE STUDY NO. 10
WEST BERKELEY BRANCH LIBRARY
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Zero Net Energy Case Study Buildings: Volume 2
The design team, understanding the value of providing occupants with some local control in a naturally ventilated building with a broad range of temperature swings, provided for a single manually operable window in most spaces to enhance the sense of control and comfort. In the meeting room, however, the automatically-controlled windows are, because of the low ceiling, within reach of the occupants.
Because of the actuator issue described in the previous section, on the first occasion when the meeting room became stuffy and uncomfortable, one of the automatically operating windows was forced open and broken. This is perceived as a design issue that can be addressed with an alternative approach in this type of room, such as utilizing operating in-wall air dampers rather than controlled windows.
Another issue pertains to the design of the hydronic convection heating grilles located just inside the automatically operable windows. The grilles are manufactured with metal flat bars at a spe- cific geometry and spacing to ensure that cold outside air is heated to room temperature over the short distance as the air passes over these flat bars. After the grilles were installed, some library staff complained that the appearance of the flat bar grilles suggested incarceration. The client ordered a change in the geometry—a wider spacing of the convective flat bars that make up the grille, to mitigate this visual association. The effect was also to reduce the heat transfer and warming of incoming air, resulting in complaints of cold drafts near the operable windows.
Finally, the large room fans were placed under manual control only, which resulted in infrequent operation even when the cooling effect would be substantial, or excessively high speeds be- cause of lack of understanding of the purpose of this feature. In public spaces where users are likely to lack information about the operational design of a ZNE building, it is probably better to have the large room fans operate automatically as part of the passive cooling modes, with a manual “off” switch at each fan for local user control.
Post Occupancy: Commissioning
Standard commissioning was carried out for this case study project and was completed approxi- mately at the start of occupancy in January 2014. Similarly, the related programming and devel- opment of the master control system for all but the lighting systems was wrapped up at the same time. Neither the commissioning agent nor the controls contractor continued with the project after the start of building occupancy. The building operations and maintenance was turned over to the maintenance supervisor for Berkeley Public Library with little transition instruction or training.
Issues with operations, metering and unusual energy use continued for some time after occu- pancy, as would be expected in this situation. Activities during this initial period should be re- garded as ongoing commissioning and are best accomplished with continuity from construction through initial occupancy. The two principal objectives during post-occupancy are:
• Continuous “re-commissioning” of the equipment and system functionality for energy ef- ficiency;
• Calibration(andre-calibration)ofpowermeters,flowmeters,sensorsandgauges.These devices tend to drift from their initial set points soon after the first commissioning is done.
Post Occupancy: Lighting
The daylighting design for the main public space features the large skylight arrays that provide adequate lighting for 90% of the open hours. For remaining hours and dark days, the LED stack lighting provides the balance of light required to meet library lighting level standards for horizon- tal and vertical (face of book titles in the stacks) illumination, as noted in the discussion of the