Page 128 - Zero Net Energy Case Study Buildings-Volume 3

CASE STUDY NO. 16
LACCD HARBOR COLLEGE SCIENCE BUILDING
(Right) Photo by Tim Griffith 114
Master System Integration and Control Systems
The building controls system is part of a campus-wide controls system that is based on BacNet protocols. The building automation system (BAS) monitors all of the energy systems of the build- ing by processing and recording data from the sub-metering network that was installed per the construction specifications. The intention was that the output from this network of meters would not only provide a means of monitoring the performance of the energy system components for the maintenance staff, but also to form the basis for the Measurement & Verification Plan, re- quired as part of the submittal for LEED-Gold certification. (See the diagram of the sub-metering system on the opposite page.)
The design intention was that during the first year of occupancy, the actual energy use as mea- sured by the meters could be compared with the modeled energy use. If there were a significant difference between the two in any category of energy use once the model was recalibrated for actual use conditions, the District could take corrective action. Thereafter, the District could monitor the data reported from the meters through the BAS to check on the building energy performance.
It was found at the time of the writing of this case study, however, that the data from the installed sub-meters was not being properly recorded by the central BAS. The result is that there is no data record until recently of the energy use by category of use (lighting, fans, plug load, etc.). This is discussed further below in the Post Occupancy section.
Renewable On-Site Energy Supply
The 264 kW (DC) solar PV system that is installed on the Science Building is integrated with a structural framework to provide shading of the south façade and the roof. This building-integrated system creates the strong architectural feature that is the visual hallmark of this building.
In addition, there is a vast array of solar PV panels located on canopy structures above the three parking lots to the west of the campus and above the west parking structure, totaling 2,366 kW (DC). Together with the building-mounted solar panels on the Science Building and the Learning Resource Center (58 kW), the total installed capacity on the Harbor College campus is 2,688 kW (DC), a sizable source of renewable energy for the campus buildings as a whole.
The principal value for the Science Building is that a portion of the larger system arrays es- sentially can act as an “offset” of the natural gas consumed at the Central Plant for making the heated and chilled water used for heating and cooling this building. So that portion of the large parking lot arrays serves to bring the Science Building to overall ZNE performance, at least by one method of energy accounting. See Energy Production versus Energy Use: Zero Net Energy Performance below.
Zero Net Energy Case Study Buildings: Volume 3