Location: Columbia, South Carolina
Industry: Local Government
Products Used: Chillers, Energy Management & Controls,
Services Used: Energy Analysis & Monitoring,
Climate: Humid & Hot
Topic: Efficiency, Cost-Saving,
Comfort issues and energy costs were increasing, as the original heating and cooling systems operating in the South Carolina Department of Transportation headquarters building had become less reliable and efficient. In addition, the 0.4 miles of underground piping, connecting the building to its remote central steam and chilled water system, were forty-two years old and degrading. “We wanted to come off the central plant, address issues on our own, and decrease our energy cost,” said Roger Sears, PE, SCDOT Headquarters.
Following South Carolina procurement statutes, the SCDOT issued a Request for Quote (RFQ), followed by a Request for Proposal (RFP), which included an Investment Grade Audit. Trane responded to the RFQ/ RFP solicitation with a comprehensive Guaranteed Energy Savings Performance Contracting solution that would allow the department to pay for the improvements with energy savings generated by the project, eliminating the need for an upfront capital outlay. The solution included equipment and controls upgrades, lighting improvements, and water conservation measures. The SCDOT selected Trane for the project based on a successful relationship centered on Trane’s unique understanding of the department’s critical facility issues and needs, and the solutions the company offered during the solicitation process.
Alleviating expensive contract services
A new water-cooled chiller plant was constructed on the ground level parking deck of the SCDOT building. The plant includes a 600-ton variable speed Trane® CenTraVac® centrifugal chiller in a variable primary flow configuration. Trane CenTraVac chillers offer the industry’s highest efficiency and a simple, robust design for reliable operation. The plant also includes chiller plant controls, cooling tower, pumps with variable frequency drives (VFDs), and electrical switchgear.
A new high-efficiency condensing boiler plant and boiler room was built in the penthouse of the building. The plant eliminated use of steam from the central system, using natural gas as its energy source, and increased redundancy with two identical boilers. “We now have on-demand gas boilers,” said Sears. “They only heat when needed and are much more energy efficient.”
Upgrading technologies, implementing conservation measures
To upgrade the air-handling system serving the core floors of the building, the team added new hot water coils and VFDs; established four variable air volume (VAV) perimeter zones per floor; and implemented direct digital controls (DDC) on the primary and perimeter air-handling units and 330 VAV boxes. A fifteen-fan array with VFDs replaced the antiquated vane pitched van axial fans and filter technologies for enhanced redundancy and efficiency. The air handling system also includes a dynamic, lower horsepower V8 filter bank to replace inefficient, high-energy use bag filters. The SCDOT implemented plumbing fixtures with low-flow devices throughout the building; added sub-metering to monitor cooling tower water use; and is in the process of implementing a comprehensive interior and exterior lighting upgrade to replace its T8 lighting with LED fixtures to reduce electricity use.
Optimizing building operations and energy management
Trane converted the building’s pneumatic controls to a Trane® Tracer® SC platform with Tracer® Ensemble™ Cloud for building automation and management. Tracer Ensemble Cloud provides software as a service (SaaS), hosted and managed by Trane. It connects to SCDOT systems, but does not require a server or IT support, reducing both up-front costs and ongoing support.
Ensemble provides a remote enterprise view of the entire building using a PC, tablet or smart phone, offering convenience and enabling greater staff productivity. The system’s interface features fully customizable navigation and an enhanced touch screen allowing facilities managers to easily perform daily tasks, address comfort needs, establish scheduling, adjust set points, manage alarms and troubleshoot issues. Using Ensemble, the SCDOT management team can monitor vital performance metrics, manage energy use, access long-term data collection, generate reports, and perform analysis to identify areas for improvement, helping to make informed decisions to proactively run the facility.
Proving effective project management for seamless installation
The Trane installation team completed major electrical upgrades to support the chiller plant, addressed code requirements, coordinated asbestos abatement during the VAV box retrofits, and performed seismic constraint upgrades for new gas piping. With the building being 100 percent occupied, and also designated as the state’s emergency broadcasting center, project implementation required significant coordination between SCDOT and Trane project management, with much of the construction scheduled on weekends, so as not to disrupt normal business operations.
The SCDOT entered into a Guaranteed Performance Contract with Trane to implement comprehensive upgrades at the department’s headquarters facility. The complex project was completed in just thirteen months, in spite of a fully occupied building. The upgrades improved comfort and air distribution, enabled the SCDOT to disable connections to expensive centralized utilities, and alleviated the department’s liability for an aging buried piping infrastructure. The building is realizing a 19 percent reduction in kWh and an 85 percent reduction in therms. Guaranteed Energy Savings for the project is more than $250,000, with an operational cost savings guarantee of more than $80,000.
Capacity, comfort issues
Rising energy costs
Guaranteed Energy Savings Performance Contract
Water-cooled chiller plant / high-efficiency boiler plant
Tracer® Ensemble™ building automation / management
$1.7 MM capital cost avoidance
Guaranteed $250,000 energy savings, $80,000 operational cost savings
$100,000 utility rebate