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Challenge

Managing a thirteen-story building with both offices and a data center required Childress Klein to perform a balancing act between keeping the facility's 500 employees comfortable, while maintaining the cooling required by the building's 24/7, mission critical data center. With 40 percent of the building’s budget consumed by mechanical systems, the company also sought ways to lower operating expenses and energy costs.

Solution

Two 350-ton Trane® CenTraVac™ centrifugal chillers in the chiller plant were operating 24 hours a day, although evening load was lower. To save energy, a strategy was devised to use a smaller 120-ton Trane air-cooled roo op unit, designated for emergency scenarios, as the a er-hours chiller. While the solution offered some savings, Childress Klein sought more control to optimize the cost-effectiveness of the equipment and worked with Trane to identify potential upgrades.

Developing an energy strategy
Leveraging Trane Building Advantage™ energy management services, a Trane Energy Assessment from the Intelligent Services portfolio was conducted. Using Energy Optics* and Energy Analyzer tools, Trane analyzed energy consumption over several years, benchmarked the facility against other likekind buildings, and identified potential energy conservation measures (ECMs). The Trane solution involved using the building’s existing equipment, but managing it differently.

Increasing comfort and reliability
The building’s two existing chillers were retrofi tted with Tracer® AdaptiView™ control panels. Intuitive and customizable, the touchscreen displays on the AdaptiView provide a snapshot of building systems. Facility managers use AdaptiView to access and control chiller operations to improve reliability and identify energy saving opportunities. AdaptiView also interfaces with the building's Tracer Summit™ building automation system to trigger alert notifi cations. “With AdaptiView, we can check every part of the chiller, temperature set points, when the compressor starts, and how long it’s been running,” said Juan Bedoya, general maintenance mechanic, Childress Klein. "Plus, if there is an issue, an alarm is sent directly to our phones."

Implementing the new chiller plant strategy
Pressure independent control valves were installed on the thirteen air handlers in the building to improve system efficiency, allowing Childress Klein to regulate discharge air to extract as much heat as possible. The plant was converted from constant fl ow to variable-primary flow technology to efficiently distribute water throughout the facility and connect building load to the production and use of chilled water. As the load profile drops, operators use AdaptiView™ to reduce the flow, and control the refrigeration inside the centrifugal chiller, removing inconsistencies and reducing energy costs. “AdaptiView gives us the ability to vary the water flow and control the chillers in a different way to enable energy savings," said Jack Kennedy, director of engineering services, Childress Klein. "By doing this, we can utilize pressure independent valve technology to achieve more stable coil temperatures to remedy the drafty conditions that have been inherent to the building since it was constructed."

Gaining knowledge to enable active energy management
AdaptiView helps building managers gain insight into chiller operating patterns, energy use and system performance over time, provides customizable graphs to display data for analysis of variations and trends, and helps operators deploy energy saving strategies. “We use information from AdaptiView to incorporate into our strategy the most cost-efficient method to cool the building,” said Kennedy. “AdaptiView collects active tonnage data, so we can calculate when to use the smaller rooftop unit. Information taken from the panel helps us know how to vary the evaporator flow, and we use AdaptiView pressure ratings to make  decisions on air pressure control."

Results

Energy strategies implemented at the Atlanta office and data center building managed by Childress Klein include variable flow technologies, installation of pressure independent control valves, increased utilization of a third chiller, and retrofitting of existing chillers with AdaptiView control panels. The project is resulting in energy savings of approximately 30 percent annually as verified by a third-party engineer, and has a payback of less than five years. The reliable, quiet operation of the systems, as enabled by the AdaptiView, is also helping enhance comfort for individuals working in the building. “We require a lot of Trane," said Kennedy. “Our account manager and his team have always been responsive, and always prepared for any request we’ve ever made.”