Building Automation Systems
Building Automation Systems (BAS) is part of the University of Michigan’s Facilities Maintenance department. BAS serves nearly all of the University's General Fund Buildings, and a few non-general fund buildings (for a fee). BAS implements schedule and operational changes for various types of equipment, and monitors alarm conditions and energy efficient system operation.
Direct Digital Control, known as “DDC” is at the heart of building automation. DDC measures environmental conditions and compares the measurements to the desired settings (a.k.a. setpoints). It calculates an appropriate response if the two aren't equal, and sends out control signals to correct for any difference. Start/stop control and alarm reporting are also incorporated into DDC.
Controlled Equipment at the U. of M.
At the University of Michigan, DDC is typically used to control fan systems, namely the supply and return fan speeds, fresh-air mixing dampers, heating and cooling coils and humidification systems, all to maintain the desired fan discharge temperature and humidity and ultimately the occupied spaces of buildings. Additionally, BAS may control and/or monitor fume hood exhaust fan and energy recovery controls, using the available heating/cooling from the exhaust air to heat/cool the outside air that’s being drawn into the building by the supply fans. CO2 monitoring also provides for controls that adjust fresh air to auditoriums as the occupancy level changes. BAS also controls complex chilled water systems, including primary/secondary/tertiary chilled water loops, cooling towers start/stop and where available variable-speed controls, free-cooling systems, as well as outside and inside lights, hot water pumps and a rapidly growing number of individual DDC room controls.
Prior to DDC
Regardless of whether you have DDC in your rooms, the local thermostat should be able to adjust individual room/zone temperatures. If all of the areas served by a particular fan system are too hot or cold, the fan system’s DDC may need attention. However, if there is a problem in one specific area while other areas served by that same fan system are fine, it usually means the local controls are at fault.
The building occupants determine the schedules. Typically each building has a representative who collects schedule information before passing it along to BAS. Schedule changes can be sent to: Building Automation Systems, 326 E. Hoover, Campus zip 1002.
We have several computer consoles that are connected to our campus-wide networks, from which Utility Systems Technicians and Control System Specialists can make program changes that alter schedules and modify control operation. Changes are sent to remote panel-mounted computer servers which control the building systems. The servers perform stand-alone control for autonomous operation whenever networks are unavailable.
For Information or Assistance
BAS can be reached 24 hours/day at (734) 763-4013, and the Plant Operations Call Center is available to take comfort and maintenance requests at 647-2059, also 24 hours/day.
A division of the Utilities and Plant Engineering organization, Energy Management strives to fulfill the University's commitment to minimizing energy consumption and containing energy expenditures. The Energy Management Section concentrates its efforts to promote energy conservation and energy efficient building operations in over 100 general fund buildings on the Ann Arbor campus.
Questions or comments about this document can be directed to Tim Kennedy.
Content modified: August 9, 2011