The COOLER Research Program
How can smarter buildings enhance the resiliency of Stanford’s utility chilled water system?
This question was asked by Professor David Goldhaber-Gordon and his faculty-led Energy Supply Advisory Committee (ESAC) in 2019 as they investigated solutions for recent chilled water supply challenges.
While the short-term response recommended by the ESAC was a major expansion of the campus' chilled water capacity, better exploration of the drivers of cooling demand and related flexibility issues was also recognized as valuable in the medium-term to improve resilience of the campus' shared energy infrastructure.
In response, the COOLER Research Program was launched to provide a quantitative assessment of the impact of different chilled water demand management strategies. The program leverages new technological resources available to the university, including smart building control systems and new data management platforms that enable acquisition and analysis of large and complex data sets.
The program is a collaboration between Stanford Land, Buildings & Real Estate (LBRE), Dr. Jacques de Chalendar and Professor Sally Benson from the Energy Resources Engineering Department, and senior faculty affiliated with the Stanford Precourt Institute for Energy. It entails experimenting with different chilled water load management measures within multiple operating buildings. A unique aspect of this research is the ability to test at the individual room level. This unlocks the potential for much more precise and targeted control strategies, opening the door to gradual demand reductions in non-critical spaces while simultaneously preserving critical zones.
The core strategy that is being tested in 2021 is to increase the temperature setpoint in select heating and cooling zones in participating buildings. The main research goal is to understand the impact of this strategy on building-level cooling loads. We seek to understand how the response varies as a function of: 1.) Important weather variables, such as outside air temperature; 2.) How many zones are included in the strategy; 3.) The time of day at which the temperature setpoint is increased.
By summer 2022, COOLER has on-boarded a dozen campus buildings. Research thus far has demonstrated significant, consistent, and predictable impacts on chilled water loads from simple measures like raising room temperature setpoints by 2 to 4 degrees Fahrenheit, while maintaining zone temperatures within target boundaries. Extrapolating these results to the campus level suggests the University could reduce system-level demand by 10-15% during periods of stress. Beyond emergencies, the research data that were collected will also be of value to LBRE in more regular operations, e.g. to more accurately estimate the energy saved by raising room temperatures in unoccupied spaces.
