Challenge
Parkway Properties was challenged with making the twenty five-year-old One Orlando Centre, with original HVAC systems, compete head-to-head with the newly constructed building market. Although prior retrofits, including a T-8 lighting conversion, reduced energy consumption, the building was experiencing gross inherent inefficiencies compared to current systems and design standards. Issues included garage roof and 18th floor chiller plants, which were never connected properly to enable optimized performance, and inconsistent temperatures compromising comfort and the working environment for tenants.
Solution
Impressed with the customizable solution presented by Trane, Parkway Properties selected the company for its upgrade project. Trane began by performing TRACE™ 700 modeling and field testing to determine the effects of integrating the building's two chiller plants. It was determined that connecting the plants and optimizing the pumping strategy would significantly reduce the connected load and improve energy performance. The two chiller plants were re-piped into a variable primary flow loop, allowing the system to reduce pump horsepower and eliminate several chiller water pumps. New cooling tower technology uses a fan array concept that further reduces connected kW, an ability to recapture (water) drift, and incorporates a near zero bleed water treatment.
Improving efficiency and redundancy
Two 375-ton Trane® Series S™ CenTraVac™ chillers deliver optimal performance to keep tenants comfortable. For increased redundancy, a 300-ton Trane Stealth™ air-cooled chiller was also installed to handle peak and night loads. Featuring AdaptiSpeed™ technology, the integration of a direct-drive compressor, a permanent magnet motor, and third generation Adaptive Frequency™ drive (AFD₃), the chillers provide industry leading efficiencies and ultra quiet operation.
Controlling and monitoring building systems
Building operators use a Trane® Tracer™ SC building automation system (BAS) to control and monitor HVAC, lighting and other systems, from virtually anywhere, using Web-connected devices, such as tablets and smartphones. Tracer SC enables optimal start/stop scheduling, night setback, chiller plant control, fan and pump pressure optimization, reporting and alarm notifications. Tracer™ ES, a Web-based systems integration solution, gives Parkway Properties an online, enterprise-wide view of multiple properties and systems, from any PC or mobile device on the network. The customizable system lets managers perform daily operations such as scheduling, alarm management and troubleshooting; enables better decision making and faster issue response; and allows tracking and analysis of all their buildings over time.
Utilizing reliable, wireless technology
Trane® Air-Fi™ wireless technology eliminates communication wires between the BAS, unit controllers and zone sensors, reducing controls installation costs. The wireless solution provides twice the signal range of other wireless systems and offers flexibility to reconfigure space for changing occupant needs. Air-Fi's redundant, self-repairing mesh technology helps ensure reliable communication, automatically rerouting around obstacles to avoid disruption of building operations.
Results
By inter-connecting the two chiller plants and optimizing the pumping strategy, Parkway Properties has been able to significantly reduce its connected load at One Orlando Centre by approximately 467 kW. New cooling towers incorporate a near zero bleed water treatment program, with first year actual savings of approximately 1.5 M gallons of water per year.
Trane® Series S™ CenTraVac™ and Stealth™ air-cooled chillers have increased redundancy, and operate quietly and reliably to create a comfortable environment. Using a Tracer SC BAS,Parkway Properties has been able to further reduce energy consumption and carbon footprint, and keep a watchful eye on issues that could compromise tenant comfort.
A 34 percent average energy use savings has been achieved in the first twelve months actuals. Parkway Properties continues to monitor results, using multiple Intelligent Services: Trane Building Performance to analyze system performance; Trane Energy Optics™, which uses utility interval data to show usage trends and identify needed adjustments; and Trane Energy Performance, a cloud-based online dashboard to provide visualization of energy use, enabling implementation and validation of demand reduction strategies to sustain savings and support the discovery of improvement opportunities.