First, you need to measure the temperature in the room, compare it to what you want the temperature to be, and then move a damper to send more or less hot/cold air into the room to make the occupants comfortable.
Second, someone has to turn the lights off and on. At my house, the teenager turns them on, and I have to turn them off. There are too many lights in buildings to have a person go around twice a day turning the lights on and then off.
Third, when a fire alarm goes off, doors are closed and the ventilation system pressurizes the areas around the fire area so that the smoke doesn't spread.
Fourth, not just anybody can walk into a building off the street, nor is everybody permitted to walk into all areas of the building. Access control systems check your credentials (when you slap your badge on the reader) and
sometimes even tell the other systems to warm up your cubical and turn on your lights.
Fifth, there are bureaucratic constraints on operating your building. For example, building codes typically require a certain amount of fresh air to be brought into the building. In Chicago, there are laws requireing
landlords to maintain certain minimum temperatures in their buildings. And this Total Quality Management process thing means you have to have the paperwork that shows you did it. FDA requirements of the pharmaceutical
makers is a prime example.
Finally, the energy required to run your building, mostly cooling it, is expensive. Time clocks, night setbacks on room setpoints, and other optimizations are definitely worth it.
Bottom line: you need controls in your building to keep the occupants comfortable and save the owner money.
Best,
B.O. Mar. 4, 2005
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Robert Old, System Architecture, [email protected]
Siemens Building Technologies, Inc., Building Automation
1000 Deerfield Pkwy., Buffalo Grove, IL 60089-4513 USA
Phone: +1(847)941-5623, Fax: +1(866)699-0126
If you want air conditioning or heating something has to tell the heating/airconditioning when to come on and how long to stay on and where and how to circulate air.
If you live in San Diego, just open the windows and forget the controls (if you building has windows that open).
Building controls are intended to save money and provide comfort. Any sizable building has hvac, lighting, etc. that can be done most economically by a building control system. In the old days, someone who knew the building decided when more steam was needed and when to switch from cooling to heating, when outside air could be used, etc. A building system can watch many more factors and anticipate better and works cheap. Lighting can be controlled independant of occupants and can provide only the amount needed rather than lighting the whole building when there is one worker in.
