5 Coliseum Center
The 5 Coliseum Center building is located at 2810 Coliseum Center Drive in Charlotte, NC. It is a six story building based on a braced steel structure with a curtain wall of precast concrete panels and insulated glass providing the decorative exterior finish. The building was built in 1997 and has not undergone any significant modifications since the original construction aside from a few mechanical upgrades.
Target energy use for this type of building taken from the US DOE’s Energy Information Administration CBECS energy use Table for office buildings located in the South Atlantic Region that includes Charlotte, NC. Their number is 79.3 kBtu/ft2/year. The EUI for this building is 68.5 kBtu/sf/year indicating that the 5 Coliseum Center building has an EUI somewhat below the average, indicative of the energy conscious practices and upgrades in the building.
EE&D engineers identified 5 Low Cost / No Cost Measures and 3 Capital Improvement Measures. Added together the overall annual kWh reduction is estimated at 287,253 saving approximately $19,078 per year. The total estimated cost of the identified measures is $28,400 with a simple payback of 1.49 years.
Each floor is cooled by a Trane self contained water-cooled (SWUD) unit. Each unit has four compressors in four stages to provide direct expansion cooling for the unit. Onboard logic control of the unit calls the four cooling stages on and off in order to maintain the supply temperature set point for the building. Air is supplied to the building at 53° F and 1.5” static pressure.
The SWUD units are water cooled via an older Baltimore Air Coil cooling tower. Condenser water from all six units is pumped constantly to the cooling tower by two 20 HP pumps, each with a VFD. The two-speed cooling tower fan automatically changes fan speed to maintain as low a condenser water supply temperature as possible, with a minimum of 45°F.
The heating and ventilation for each floor is provided through a variable air volume (VAV) air distribution system served by the SWUD units. Air is distributed through a ducted supply air system to terminal boxes located within the occupied spaces. Terminal boxes are controlled by the building automation system, with each box having a dedicated temperature sensor that acts as the control point. All heating for the facility is provided through the electric reheats installed within the perimeter terminal boxes. All of the SWUD units have variable speed drives that control the fan speed based on ductwork static pressures
The Building is equipped with a Building Automation System (BAS) with custom built graphics. All major equipment in the building is controlled with start/stop/status and temperature set points for SWUDs, pumps, and terminal boxes. Exterior and common area lighting is controlled ON/OFF based on the occupancy schedule of the automation system as well.