Page 49 - Zero Net Energy Case Study Buildings-Volume 1

STEVENS LIBRARY AT SACRED HEART SCHOOLS CASE STUDY NO. 2
ated for this building is fairly complex in the way that it stages on multiple levels of cooling, but in general, the library control systems are relatively standard.
All systems are tied into the BMS (building management system) including HVAC operation, lighting, and systems metering. Although the systems are stand alone they are still monitored and controlled by the Delta control system which is a BACNET system.
The BMS was heavily used during the first few months for system diagnostics, optimizing start and stop times, and reset schedules to optimize comfort and energy conservation.
Renewable On-Site Energy Supply
The 40 kW system shares the building roof with the package HVAC unit and the solar tubes. The high-efficency system (310 watts per panel) was sized simply to fill out the available roof space, with the understanding that the actual building demand would deviate from the predicted load. The modeling results indicated that the 40 kW system would be ample to produce a ZNE per- formance and the measured results have borne this out. (See the PV system production graph on p. 38.)
The solar photovoltaic panels are horizontal, primarily to avoid shading of one panel by another in the densely packed array. This conformed to an esthetic look that was preferred by both the architect and the local building agency–a local ordinance from the 1970’s restricts visible solar panel arrays on buildings. A drawback with horizontal panels is that debris and water stains can collect on the flat surfaces, requiring regular cleaning to keep performance at an optimal level.
PHOTO: BRUCE DAMONTE
Zero Net Energy Case Study Buildings: Volume 1
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(Left) Roof Plan / Power Plan (Courtesy of WRNS Studio)