Page 143 - Zero Net Energy Case Study Buildings-Volume 3

STANFORD UNIVERSITY
PREFACE TO CASE STUDY NO. 17
(Opposite page, top) System diagram of the new CEF, with the “OSHPD Plant” separated in order to meet then-current code requirements.
(Opposite page, bottom)
Isometric sketch of the final CEF design with all system components.
The Central Energy Facility — Choice Made and Moving Forward
Stanford began the process of planning the new CEF in 2011. Before that, the campus had asked Cardinal Cogen if they would be willing to extend the lease of the existing plant on a month-by-month basis if construction and start-up of the new CEF experienced any delays. The company declined, so a hard start date for operation of Stanford’s new CEF was set for 2015.
The design of the facility started by using the well-studied basis of design undertaken by the cam- pus in the previous three years. Still, some constraints appeared during the design phase that had to be accommodated. The most significant of these was a consequence of the fact that the Stanford University campus has major hospitals that are served by the CEF and are governed by the California Office of Statewide Health Planning and Development (OSHPD). This agency would not approve the new CEF since it would not fit any approved criteria and the path to ap- proval of the new design approach would simply take too much time given the 2015 deadline.
The solution was to design a small sub-system that would serve the hospitals, which would nec- essarily be conventional gas-fired equipment for heating. This “OSHPD Plant”, separated from the main CEF, meets all the OSHPD requirements—it’s a necessary anomaly in this otherwise simple energy plant design. As a result, the CEF is not purely electric power driven, but has a small fossil fuel use. However, given that this gas-fired facility was required, Stanford could use it as a back-up source of heated and chilled water for high peak load situations or a potential unplanned shut-down of one of the heat pumps.
The non-equipment space of the CEF, namely the administrative offices, control rooms and meeting spaces of the Department of Sustainability and Energy Management, with its on-site so- lar PV array, has performed at ZNE and merits independent treatment as a ZNE building design. (See Case Study No. 17, Central Energy Facility Office Building, following this Preface.)
Construction began in late 2012 and by March, 2015, the CEF was started up after 22 miles of the distribution network around the campus were modified and the connections were made to the new heat exchangers in 155 campus buildings. This significant effort took more than two years, but eventually the entire campus was converted to the modified system, with heating and cooling energy supplied by the new CEF.
It remained to connect to a solar electric power supply to realize the full potential of minimizing the carbon emissions that the CEF could make possible.
(Below, left) Aerial view of the construction site after grading and preparation.
(Below, right) Aerial view of the construction site at an early stage. Note how con- crete pads for large thermal storage tanks are set well below grade.
(Construction photos courtesy of Whiting-Turner Contracting Company.)
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