Infrastructure Upgrades Expected to Net City of Marietta Nearly $100k in Annual Savings

Nestled just north of Atlanta and just south of the North Georgia Mountains, the City of Marietta, Ga., offers visitors the charm of a small city along with a stimulating urban environment. With a beautiful and vibrant downtown square filled with restaurants and antique shops, the city offers its 56,000 residents access to beautiful parks, quaint streets, Victorian homes and historic sites.

The city of Marietta, Ga., just completed infrastructure upgrades to its city hall and public safety buildings which are anticipated to reduce annual energy, operations and maintenance costs by nearly $90,000.

Trane, a leading global provider of indoor comfort systems and solutions and a brand of Ingersoll Rand, provided high-efficiency heating, ventilation and air conditioning (HVAC) solutions combined with energy saving advanced system controls for the upgrades. Trane was awarded the retrofit project for providing the best solution at the lowest cost during the competitive bid process.

Marietta leaders expect the infrastructure upgrades to save $71,000 in annual energy costs and reduce annual maintenance costs by $19,000. In addition, the upgrades will improve the comfort and productivity of city employees and visitors to the city buildings.

The $560,000 in HVAC infrastructure upgrades were funded through an Energy Efficiency and Conservation Block Grant (EECBG) provided by the U.S. Department of Energy under the American Recovery and Reinvestment Act of 2009 (ARRA).

Energy-Saving Upgrades Meet City Needs

Prior to the upgrades taking place, engineering company CDM Smith performed an energy audit of City Hall and the public safety complex buildings, which include the police department, courts and fire department headquarters station. The energy audit identified energy conservation measures that will best provide increased economic efficiency with maximum long-term benefits. CDM Smith also provided engineering services to the city throughout the entire project including design, bid and construction management.

The completed upgrades provide enhanced monitoring and control of HVAC systems throughout the facilities, while making facilities personnel jobs easier and less costly to perform. The installation work was completed with minimal disturbance to city operations, allowing staff to maintain full use of the facilities throughout the project.

The retrofits at City Hall included the installation of direct digital control (DDC) building controls to replace the original pneumatic building controls. The new DDC building controls utilize wireless thermostats with timed override buttons for limited HVAC during unscheduled hours.

The project included replacement of all air distribution variable air volume (VAV) boxes. A new building automation system can be accessed remotely online for trouble-shooting of building systems and operations.

The new building automation system includes complex control algorithms for the HVAC system to reduce energy use and maximize efficiency, including control of existing chilled water systems, air handling units, all new VAV boxes, and two new high-efficiency condensing boilers (the new boilers were installed under a separate contract). Additionally, new premium-efficiency HVAC motors replaced old motors, and variable frequency drives were added at pump and fan motors to work with the new control algorithms.

The upgrades at the public safety complex buildings included integration of the existing building automation system into the new Trane building automation system, along with advanced control algorithms to maximize energy efficiency. Existing thermostats were replaced with new digital thermostats equipped with timed override to reduce energy usage and maximize efficiency.

The Results Benefit the City, its Staff and its Residents

The upgrades implemented by Marietta make good sense beyond the fiscal and environmental benefits, as research has shown that steps such as those Marietta has taken to improve the working environment can actually increase employee productivity and reduce sick days.

The project reduces the city’s carbon footprint by approximately 490 metric tons of greenhouse gas emissions (metric tons of carbon dioxide equivalent) per year, the equivalent emissions savings from planting about 12,000 new trees or removing 96 cars from the road per year.

Perhaps more important to the city and its taxpaying residents, however, the successful implementation of the projects has allowed the city to realize a meaningful reduction to its budget.

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