Carter Keep Federal Courthouse Chilled Water Loop, San Diego, CA
Project Summary
The 480,000 square foot, 19 floor James M. Carter & Judith N. Keep U.S. Courthouse in San Diego, CA was built in 2012 to serve the Judiciary Branch. It was originally designed in 2008 with a chilled water cross-connect to the Schwartz Federal Courthouse in mind. GSA made sure the required infrastructure was installed between the two facilities simultaneously with the original construction. This energy savings project would not have been financially feasible if the piping between the two facilities had not been installed while the Carter-Keep Courthouse was being built. The project was also able to leverage the close proximity of the two buildings and the moderate climate in San Diego.
In 2020, GSA started a project to establish a shared chilled water loop between the two courthouses. A small, disadvantaged business that was hired as the design-build contractor completed the chilled water piping loop back to each central plant and made adjustments to both building automation systems. This allowed the combined unit to share 400 tons of chilled water and run the campus in the most efficient manner, reducing fossil fuel use.
Sustainability Features
While the project created opportunities for cost and energy savings, it also created system redundancy should one of the central plants unexpectedly go down. Significant energy savings are created during times of low demand when one central plant can satisfy the cooling needs of both buildings. These low demand periods are typically seen during the winter and “shoulder” seasons, as well as nights and weekends when the building must continue to provide cooling to computer room air conditioning (CRAC) units in server rooms and overtime utility needs. Further savings are realized through reduced run time on chillers, pumps, cooling towers, etc. by running only one central plant at a time.
Resulting impacts of this project include significant annual utility cost savings as well as an annual greenhouse gas (GHG) emission savings of 565 MT CO2e. These results help GSA work towards the goals of Executive Order 14057 by reducing scope 1, 2, and 3 greenhouse gas emissions through lowering the overall energy use intensity (EUI) of the two buildings by 5.66 kbtu/gsf. It also reduces the run time on building equipment, which extends the useful life of chillers, pumps, and cooling towers. Extending the life of existing equipment further reduces carbon output by delaying the need to manufacture, transport, and install new building systems.
