Replacing the 43-year old Trane Centrifugal chillers and cooling towers had its share of challenges, and the plan put together had many critical timing components to be considered. The project needed to be completed during the winter to minimize the impact on the tenants and their businesses, leaving a short window of opportunity for the new equipment to be installed.
Located at Eighth Street and Nicollet Mall in downtown Minneapolis, the 419,000-square-foot McGladrey Plaza building has been owned by United Properties since 1994. McGladrey Plaza was built in 1968 and underwent a sweeping renovation in 1996 that earned it "Best Remodeled Building of the Year" awards from the National Association of Industrial & Office Properties and the Minnesota Shopping Center Association.
The building is managed by Cushman & Wakefield/NorthMarq, the largest commercial real estate firm in the upper Midwest, which manages more than 50 million sq.ft. of retail, industrial and office assets.
McGladrey Plaza has been a service contract customer with Trane for more than 15 years and is currently using Trane Tracer Summit controls to operate the building. When it came time to upgrade the energy performance of the building, leaders at McGladrey Plaza turned to Trane for help.
The building owners wanted to look at a comprehensive solution that used innovative technology to ensure tenants were happy and had a comfortable, reliable working environment. The Trane team worked with the owner to better understand the future needs of the facility and identify available options to plan for reliable operation for decades to come.
The owners selected an option that would minimize the risk of not being able to provide cooling by keeping redundancy in each of the chiller plants. The selected, highly efficient solution reduces energy consumption and carbon dioxide emissions equivalent to removing 81 cars from the road each year.
To keep all of the solutions working correctly, Trane will support McGladrey Plaza with a 10-year chiller select service agreement which includes predictive maintenance, overhauls and Trane R’newal Service programs on all four chillers. Trane R’newal Service programs are comprehensive services that ensure the performance of the chillers and can extend the useful life of the equipment. These services bring existing units to the same level of reliability and current technology as offered by a new Trane chiller.
The leaders at McGladrey Plaza wanted to upgrade the building’s cooling system equipment to improve performance, ensure the cooling plants were operating as efficiently as possible, and reduce the risk of critical system failure. They also wanted to create a safer working environment by upgrading the life safety equipment in the mechanical rooms.
Analysis & Recommendations
McGladrey Plaza asked Trane to conduct a preliminary analysis of the existing cooling system performance, as well as the building’s future cooling and maintenance needs. Trane used this information to create recommendations for potential upgrade options that would improve building performance while supporting the building owner’s business mission of creating a comfortable and productive working environment.
Trane provided a detailed analysis of the cost versus savings for selected options to help leaders at McGladrey Plaza make a solid business case for needed upgrades. Trane also provided a summary of the total investment and a project timeline that included completing all of the upgrades during the non-cooling season.
Replacing the 43-year old Trane centrifugal chillers and cooling towers had its share of challenges, and the plan put together had many critical timing components to be considered. The project needed to be completed during the winter to minimize the impact on the tenants and their businesses, leaving a short window of opportunity for the new equipment to be installed.
The equipment on the roof and penthouse required several blocks of Nicollet Mall to be shut down over a weekend in order to safely set up for crane operations. The challenge of shutting down a busy downtown street was only part of the logistical considerations Trane had to manage, as the crane could only be operated at that height with a wind speed of less than 11 mph. The ability that the Trane team had to be flexible and mobilize a team on short notice was key to the project’s success.
The biggest challenge with the lower chiller plant was having access for bringing the new chillers into the building. Because of constraints with the design of the building, Trane had to completely disassemble the chillers, including splitting the tube shells, to make the pieces small enough to get through doorways and down stairwells. Upon completion of mobilizing the equipment, the Trane technicians reassembled the chillers.
During the initial analysis of the plant operation it was determined that McGladrey Plaza had an opportunity to leverage their Trane control system to get additional savings and better system operation by implementing Variable Primary Flow programming. Pressure independent valves were installed to control the flow of chilled water and the capabilities were programmed into the control system.
Trane replaced the four existing centrifugal chillers in the building’s west tower, as well as the chilled water condenser water pumps and the cooling towers located on the roof of the building. Trane also installed pressure independent valves to allow for variable primary flow operation. To address safety concerns, Trane upgraded the mechanical room ventilation system to meet ASHRAE 15 safety requirements.