Williams Mullen Corporate Headquarters
PACE Collaborative is proud to have provided the mechanical and electrical engineering services for the new Williams Mullen Office Tower in downtown Richmond, Virginia. This project was an extension of an existing 6-story parking garage and added ten (10) additional office floors.
The mechanical/plumbing design included dedicated 100% outside air energy recovery unit with heat wheel which delivers outside air to each self-contained air handling unit mechanical room on each floor. The design provided self-contained VAV air handling units and fan powered VAV and shut-off VAV terminal units for zoning on each floor. Two (2) cooling towers deliver condenser water to each self-contained air handling unit as well as to a decoupled system heat exchanger which delivers condenser water to water source heat pumps that serve offices on the first floor and first floor mezzanine and future retail space. This project also included two (2) vertical split case open loop condenser water pumps, two (2) inline centrifugal closed loop condenser water pumps, variable refrigerant flow (VRF) systems with heat recovery for data closets, and stairwell pressurization systems.
The electrical design included a 5,000A, 277/480V, 3 phase, 4 wire electrical service, Dominion Virginia Power transformer, and high voltage switch vault. A 4,000A, 277/480V, 3 phase, 4 wire bus duct provides vertical distribution of the electrical system through the building. A 350KW, diesel generator provides life safety and option stand-by power. A full building lighting control system controls all the common area, parking garage and exterior lighting. LED color changing exterior accent lighting was also provided.