Industry: Local Government
Products Used: Chillers, Controls,
Services Used: Energy Analysis & Monitoring,
Climate: Humid & Cold
Topic: Efficiency, Optimal Comfort, Air Quality,
Brown County is located in the south central part of Minnesota, approximately 100 miles southwest of the Twin Cities. The county is mostly agricultural, but also has many industrial and commercial businesses. Brown County has a population of 25,893, with New Ulm, its largest city, serving as the county seat.
The Brown County Courthouse in New Ulm was remodeled in 1968 with a state-of-the-art air conditioning system. In 1992 the county attached a Law Enforcement Center (LEC) to the courthouse building, with the third and fourth floors of the LEC designed to house the county jail. After forty years of service, the courthouse building’s HVAC system with pneumatic controls was reaching the end of its useful life. The equipment was deteriorating and it was becoming difficult to find anyone who could repair it. In addition, the county had no back up cooling for the LEC, leaving administrators concerned about the expense of moving prisoners elsewhere in the event of a system breakdown. The county was also facing a slowing economy and its highest energy bills ever. While always budget conscious, obtaining taxpayer dollars for improvements during tough economic times was difficult. The county sought solutions to improve the reliability of its equipment and lower its energy costs, while working within its tightened budget.
Relying on a trusted relationship that began with the installation of the LEC’s original rooftop chiller, Brown County facilities managers and county commissioners met with Trane to discuss how to improve their situation. After surveying the courthouse and seeing the condition of the aging equipment, Trane suggested an Energy Performance Guaranteed Savings contract. The performance contract would allow the county to use its energy savings to help fund a turnkey project that would address the outdated HVAC systems and pneumatic controls, as well as take advantage of other energy conservation measures.
Lighting retrofit helps fund project scope
Lighting fixtures were retrofitted in six county buildings, replacing 32 watt lights with 25 watt T-8 lighting with electronic ballasts. Due to the age of the lighting in the buildings, the energy savings was significant enough to help fund much of the rest of the project scope.
HVAC solution increases efficiency
Trane provided a complete HVAC solution that included the installation of more efficient HVAC equipment and the replacement of pneumatic controls with computerized controls. A 90-ton air cooled chiller was installed on the roof of the LEC adjacent to the existing LEC chiller. The new chiller was piped in parallel with the existing unit to serve as the primary cooling for both the LEC and the courthouse, with the existing LEC air cooled chiller working as a backup for both buildings.
Electric reheats were added in the basement of the LEC to eliminate long-existing comfort issues. To reduce energy use, the entire air handling system in the Courthouse was converted from constant volume to variable air volume (VAV) with hot water reheat with all new ductwork. So as not to disrupt county business, some work was done after hours, with the rest carefully orchestrated during working hours, keeping employees informed regarding the timing of work to be completed in their areas.
BAS provides control and monitoring
A Tracer Summit® building automation system (BAS) was installed in the courthouse and connected to the existing Tracer Summit BAS in the Law Enforcement Center. The Tracer Summit system provides integrated building control through a dedicated PC workstation. The BAS is used to perform daily tasks, such as responding to alarms, viewing reports and trends, programming and monitoring of systems in both county buildings. Using the BAS, twenty-eight zones were set up in order to match the individual comfort needs of each area.
Energy efficiency upgrades at Brown County facilities have resulted in lower energy bills, better air quality and temperature control in the courthouse building, as well as cooling redundancy and increased comfort for the county’s Law Enforcement Center. Energy audits have shown first-year energy savings to be more than $77,000, outperforming the Energy Performance Guaranteed Savings. In addition, the utility expenditures for Brown County as a whole have decreased nearly 16 percent countywide. “Our courthouse is unoccupied from about 5:30 at night to 7:00 in the morning,” said Chuck Enter, Brown County administrator. “The 90-ton chiller only runs as much as needed. We are able to shut the building down at night, and the chiller can quickly catch up the next morning. The old system had to run all night and all weekend.” “We also like that Trane used local contractors,” added Enter. “That’s important to our citizens and to the economy of Brown County.”
About Brown County
Brown County Courthouse, located in New Ulm, serves the judicial needs of nearly 26,000 county residents. To reduce energy consumption, the courthouse air handling system was converted from constant volume to variable air volume.