Design improvements to an outdated and inefficient central cooling and heating plant in a 16-story, 225,000-square-foot building in downtown Norfolk are expected to cut utility costs by almost 50 percent, with estimated savings of $90,000 per year.
Under a contract with Hourigan Construction, B&N worked closely with Warwick Mechanical Group, IES Commercial and Industrial, and CBRE to collaboratively design the improvements to the building’s central air handling units, chiller plant, boiler plant, and building automation system.
The new cooling plant is designed to provide lower chilled water and supply air temperatures to improve the cooling capacities of existing equipment. The design also will allow smaller equipment, ductwork, and piping to be used when designing future tenant improvements. Additionally, the central air handlers are now capable of supporting variable air volume (VAV) systems in the core areas of future tenant spaces which will provide enhanced zone control and save even more energy.
Improvements included:
- Replacement of two fully redundant 600 horsepower scotch marine steam boilers with three 3,000 MBH gas fired condensing boilers
- Swapping a combination of outdated centrifugal and screw chillers with new premium efficiency 400-ton centrifugal chillers
- A new 800-ton variable speed cooling tower
- Retrofitting the central air handling units with new cased heating and cooling coils, damper actuators, and variable speed supply and return fans
- Upgrading heating water and chilled water distribution systems to a variable-primary pumping scheme using new split case pumps and variable frequency drives
- An Automated Logic direct digital control system that controls the new equipment
- Boiler and chiller plants fully optimized to maximize energy efficiency
Using the Design Assist process, B&N partnered with the contracting team at the beginning of the design process which resulted in the delivery of a highly coordinated set of construction documents that minimized the potential for change orders and deviations from the construction schedule.