J. Wayne Reitz Union, Gainesville, Fla.
A Union of Comfort and Performance
The only constants during 50 years of adding and renovating various spaces at the University of Florida’s student union were the mechanical systems, lighting and controls. An energy performance contract not only improved occupant comfort and building performance but saves over 3 million kWh annually.
Since the original structure opened in 1967, the numerous additions to the J. Wayne Reitz Union changed the footprint of the building and added a significant amount of square footage. The changes also resulted in the loss of a cohesive building design and performance challenges—with disparate systems that did not communicate with each other or work efficiently together. Different sections of the building varied greatly in efficiency and needs.
In addition to a $65 million expansion to accommodate campus growth, the university developed a separate project to focus on existing infrastructure issues and implement a variety of equipment updates and energy-saving solutions—from mechanical and electrical system updates to plumbing and lighting renovations. Using an energy savings performance contract allowed the university to complete significant upgrades and implement improvements with funding from guaranteed energy savings.
Challenges to Overcome
Five major expansion and renovation projects in the 50-year history of the Reitz Union resulted in a facility with confusing circulation patterns and a mix of equipment and systems. The building had two inefficient centrifugal chiller plants that weren’t properly linked, aging air handlers and outdated pneumatic controls. Constant volume air was used in most of the building, and some systems ran 24/7 due to inefficiency and the inability of the systems to communicate.
The range of services and functions in the building (everything from a hotel and career center to ballrooms and offices) meant the facility was continuously occupied and continuously operating. While the building was functional, it was extremely energy inefficient and desperately in need of modernization. Poor system performance also led to frequent issues with occupant comfort.
The university sought to implement energy conservation measures (ECMs) that would deliver maximum savings and efficiency. The project needed to drastically improve energy efficiency of the existing building in keeping with the goal of achieving LEED Platinum certification for the building expansion project. It was also critical that the improvements not disrupt day-to-day activities in the critical campus building.
While the university was planning a large expansion of the Reitz Union, funding was not available for the infrastructure renovations needed on the existing building. This made it necessary to use a performance contract for those improvements.
Energy performance contracting is a project delivery process that implements significant infrastructure upgrades through the combination of building science, third party financing and guaranteed energy savings.
Project goals were to replace obsolete systems and increase capacity of the central cooling and heating plants, while conserving energy.
A comprehensive energy audit of the facility was conducted to determine which improvements would result in significant energy and cost savings. Because of the size of the building and the range of occupancy types, the energy modeling required four models to audit the lighting and HVAC systems.
A comprehensive renovation with more than 50 potential ECMs was proposed. The measures chosen for implementation by the university included:
• A new high-efficiency chiller;
• Replacement of outdated air-handling units;
• Conversion of existing multizone air handlers to variable air volume (VAV);
• Modernized building automation system (BAS) controls;
• Lighting upgrades;
• Water conservation measures;
• Building envelope improvements; and
• Mechanical solutions to optimize performance.
Among the many mechanical system improvements, the redesign of the facility’s two chiller plants was especially critical to optimizing efficiency and building performance.
The chilled water piping between the two plants was redesigned to create a single primary-secondary variable flow pumping system, while the chilled water pumping system was replaced and expanded to provide 1,500 tons of chiller capacity and chilled water pumping capacity to serve the new expansion. In addition, a refrigerant monitoring system was added in the chiller plant for improved safety.
The chiller plant was upgraded with a 2,000 kVA transformer, electrical service and switchgear, and the steam heating systems were replaced with a larger system to enable hot water flow throughout the complex. To provide sustainability, reliability and efficient operation, the existing chillers were replaced with two 500 ton centrifugal water-cooled chillers and a 375 ton chiller that delivers the highest full- and part-load efficiencies in that tonnage range.
The wide range of services and functions in the building meant the facility was continuously occupied—and continuously operating. While the building was functional, it was extremely energy inefficient and desperately in need of modernization. Poor system performance also led to frequent issues with occupant comfort.
Steam converters were replaced for building heat and domestic hot water in the facility. A steam metering system that dated back to the building’s 1967 construction was also replaced, as were hot water piping and pumps.
In addition, 11 of the existing constant-volume air-handling units were replaced with more efficient VAV air-handling units for cooling, and in some instances an energy recovery ventilation unit was added. Twenty recently installed constant-volume, multi- and single-zone air handlers were converted to VAV rather than replaced to take advantage of existing assets while still improving efficiency. This system reconfiguration allowed for the removal of five air handlers.
Improving System Control
The obsolete pneumatic controls and legacy control systems in the union were replaced with a new building automation system (BAS) to improve control and performance.
The updated BAS provides 24/7 access to HVAC and lighting systems for scheduling, occupied/unoccupied settings and night setback of cooling and heating setpoints. The system also provides demand-controlled ventilation based on occupancy or CO2 concentration and optimal start/stop and controls scheduled based on occupancy.
Among the many mechanical system improvements to the University of Florida's Reitz Union building, the redesign of the facility’s two chiller plants was especially critical to optimizing efficiency and building performance.
With an easy-to-operate user interface, building operators can set and adjust setpoints, start and stop functions and chiller pumps based on system load. The interface also allows users to implement chiller, pump and cooling tower sequencing and energy optimization routines and to obtain status reports on important operating data. Custom graphics and trends are included to allow monitoring and reporting of real-time chiller plant efficiency.
To save energy and money, interior fixtures and exterior perimeter lighting were replaced with more efficient solutions, and greater lighting controls were implemented.
All linear fluorescent lights were replaced with new LED fixtures or new linear LED sources. This achieved significant energy savings while also reducing the time and money spent on maintenance, due to the extended life of LED lighting products. New LED fixtures were carefully selected to improve aesthetics and light quality.
The majority of the plug-in compact fluorescent recessed cans were replaced with new LED downlight fixtures. Where possible, existing recessed cans used screw-in LED lamps. This improvement was based on maintenance savings and addressing staff concerns, as staff previously spent a lot of time replacing lamps.
The food court area was renovated to revise the ceiling design to match the aesthetics of the new expansion, so lighting fixtures were matched to create a seamless transition from the old portion of the building to the new expansion.
This chart shows the year-over-year actual energy use and actual savings performance for the renovated portion of the Reitz Union. The first year, 2014, represents the construction of the project. The savings that appear in the second half of 2014 are from the project. The year-over-year performance in 2015, 2016 and especially 2017 show the impact of continuous improvement by the Reitz Union. There is no change to the existing Reitz Union over the last three years, other than continuous optimization of schedules, setpoints, and use of the energy management system to drive greater actual energy savings.
The project made it possible for the university to replace infrastructure without the financial burden of having to find new funds, and at the same time significantly reduce energy consumption (Figure 1).
The upgrades were projected to result in annual savings of 3,278,505 kWh of electricity and 13,597 therms of natural gas, with annual energy use and rate change savings of $414,562 and annual operational savings of $121,095. The university also received an additional $90,549 under an energy-efficiency structure.
The project qualified for energy rebates for indoor lighting, HVAC system and chiller replacement, as well as building envelope upgrades and demand controlled ventilation measures.
The energy retrofit of the University of Florida Reitz Union met the numerous goals established for the project—improving the quality and functionality of the building and its key systems, while also reducing long-term operational and energy costs and supporting the university’s sustainability goals. The building is intended to have a long life and serve its unique purpose on campus for many generations of students to come. •
About the Author
Steve Corson is Energy Services Leader for Trane Florida, West Palm Beach, Fla.