Page 103 - Zero Net Energy Case Study Buildings-Volume 2

Domestic Hot Water
Hot water for use in the restrooms is provided via the solar thermal heating system using a heat transfer coil at the water storage tank.
Plug Loads
Much of the existing library equipment was to be used in the new building. In addition, the branch library planned to begin a program of providing laptop computers for patrons to use in the library for Internet access and general reading. A special literacy program, which was also going to be located in the new building, made heavy use of desktop computers that would be moved over. Initially at least, there was no funding option to replace this equipment with more energy efficient models. It was therefore essential to determine how large this plug load would be.
Measurements were made over several weeks to determine the average and peak power draw of all the equipment generating the plug load for the new building. This data was used in the whole building energy model to ensure reliable estimation of the building EUI and confirm that the building remained on track for ZNE performance.
Master System Integration and Control Systems
Unlike other case study buildings in this Volume, the design team for the West Berkeley Branch Library did not include a master system integrator to develop an omni-controller for all control systems related to the HVAC, lighting, solar PV, energy metering and energy dashboard during the design and documentation phases. Rather, separate control systems were specified and separately programmed by individual vendors, resulting in the similar problems and issues de- scribed in Volume 1 for earlier ZNE case study buildings. (See Post-Occupancy Observations and Conclusions, below.)
The controls subcontractor tasked with the programming of the HVAC building management system (BMS) was required to include coordination of the operation of all building components comprising the passive ventilation design—the automatic windows and skylights in relation to the Mixed Mode of Operation for the entire HVAC system, the weather measurement system and the CO2 sensors. With construction partially completed, the subcontractor also took on the task of incorporating the controls for the solar PV system, the energy metering system and the setup of the energy dashboard. This required a change order and extra cost to the project since this work had not been defined and planned beforehand. The development of an “omni-control” system essentially evolved during the construction phase, carried out by the BMS controls vendor.
The final “omni-control” system, however, is not quite complete since the control systems related to daylighting and electric lighting, including daylight sensors and dimming controls, were ex- ecuted separately by the electrical subcontractor.
The controls subcontractor did not continue in any kind of maintenance or advisory role after the completion of construction. Tracking of the building energy performance since that date has been done by the director of the Office of Energy and Sustainable Development for the City of Berkeley on an intermittent basis. Building systems operation has been the responsibility of the maintenance staff of the Berkeley Public Library.
Commissioning
Commissioning was carried out by a third-party commissioning agent and included all the com- missioning requirements for LEED certification. However, once the commissioning activities in the construction phase were completed, no further commissioning was done by this agent. (See Post-Occupancy Observations and Conclusions, below.)
Zero Net Energy Case Study Buildings, Volume 2
91
WEST BERKELEY BRANCH LIBRARY
CASE STUDY NO. 10