Ramsey County Library, Roseville, Minn.
Retrofit Team
Retrofit Team
BUILDING-AUTOMATION PROVIDER: Uhl Co. Inc., Maple Grove, Minn.
Materials
Ramsey County asked Uhl Co. to conduct a recommissioning study at the library in 2013. The goal was to review the building’s existing equipment and identify ways to make it run more efficiently and generate cost savings. The study included functional testing of major equipment and the use of analytics to identify seasonal energy-conservation opportunities.
Energy-efficiency enhancements Uhl implemented included air-handling unit and rooftop unit run-time improvements, demand ventilation adjustments, chiller compressor sequencing, RTU outside air CO2 control and economizer improvements, AHU discharge air and duct pressure resets, AHU economizer improvements and adjusting library space temperature setpoints. The building’s HVAC system is controlled by an advanced building-automation system. The facility staff uses analytics to continually monitor building performance and is constantly commissioning the building’s operations to keep all systems optimized.
Uhl is a member of the InsideIQ Building Automation Alliance, an international organization of independent building-automation contractors. Learn more at insideiq.org.
CHILLER MANUFACTURER: Trane
BOILERS MANUFACTURER: Aerco
NEW AIR-HANDLING UNIT AND NEW ROOFTOP UNIT: McQuay
BUILDING AUTOMATION SYSTEM MANUFACTURER: Schneider Electric
The Retrofit
Ramsey County Library is a 70,000-square-foot facility constructed in 1993. It received a major addition in 2010 that qualified the building for LEED Gold. In addition to library uses, other building functions include offices, conference rooms and a coffee shop.
Uhl’s recommissioning study identified many energy-conservation opportunities and the county chose to implement most of them. Utility rebates of $7,673 from Xcel Energy, the local utility, helped cover the upfront costs of the project. Once implemented, the energy-conservation measures lowered natural gas use 5,038 therms and saved 54,420 kWh in electricity for a utility cost reduction of $10,518. Overall, savings were 5 percent more than projected and the payback period for the library was just more than six months.
“Ramsey County implemented the recommissioning along with analytics to help determine best practices in development of a sustainability model for our facilities. This project has proven to us that even in a LEED-certified building less than five years old we still have opportunities to save energy,” says Gary Mrachek, director of building operations for Ramsey County Property Management. “The analytics continuously evaluate system performance and notify the team if the system is not performing as optimized during the recommissioning. This actionable information allows the team to move quickly in resolving issues that could affect building operations and increase energy consumption. We see this as a model the Property Management Department will use in all of our facilities going forward.”
“Commissioning ensures that specific building systems perform interactively according to the design intent and the owner’s operational needs,” adds Joseph Ciernia, Uhl’s director of energy services. “But even if a building was properly commissioned when it was built, changes in use and operations over time typically lead to diminished building performance. Recommissioning is the process of making adjustments so a building is once again properly calibrated to achieve optimal performance. In our experience, recommissioning consistently saves between 5 and 25 percent of building-energy costs while improving occupant comfort and operations.”
PHOTO: InsideIQ Building Automation Alliance