GBA developed an upgrade strategy including the following elements:
- Two existing constant-volume multi-zone air-handling units were replaced with one new variable-air-volume AHU with fan-wall-type supply and return fans, expanded economizer operation, outside air intake monitoring, and a chilled water cooling coil.
- Two water-cooled chillers that used potable city water for heat rejection were replaced with a new air-cooled chiller, with variable-speed compressors and chilled water pumps.
- Two low-pressure steam boilers were replaced with high-efficiency condensing-type hot water boilers. All of the old steam and condensate piping within the building was replaced with new hot water piping.
- The building’s existing pneumatic controls were replaced with direct digital controllers, linked on a communication network with a new server providing easy browser access to the maintenance and operations team, as well as reporting equipment status for validation and troubleshooting.
- Outdated electrical service was replaced with a new electric service and main switchboard.
- Additional replacements included toilet and locker exhaust fans, heating and ventilating equipment serving garages, replacement of the existing electric domestic hot water heater with a high-efficiency gas-fired heater, replacement of a make-up air unit serving a gun range, and replacement of heating elements and control valves in convectors throughout the building.