Building Automation Systems(BAS)
Building Automation Systems (BAS)
The process of specifying, designing, and installing building automation systems (BAS) typically begins with the plans and specifications produced by the mechanical, electrical, and plumbing (MEP) design engineer. The MEP plans and specifications include equipment and process schematics that specify the location of sensors and control elements for the mechanical system. Also included is a narrative “Sequence of Operations” which describes how the mechanical system is to be controlled. Despite its name, the “Sequence of Operations” does not describe a sequential process; it is an overall specification of the control strategy for the heating, ventilation, and air conditioning (HVAC) system. This information is provided to the control system integrator, who then creates a configuration database for the control system, which establishes communication, network, and device parameters as well as input/output (I/O) configuration parameters. The control system integrator also develops control application programs for the controlled equipment based on the narrative “Sequence of Operations.” There is a great deal of variability in the level of detail provided in the “Sequence of Operations.”
How does Building Automation work?
HVAC and Lighting Controls – Stand alone computerized controllers are installed to take over the control of building HVAC (heating, ventilation, and air conditioning) systems and lighting. The building is not only scheduled more closely but it is also operated more intelligently and efficiently.
Outside Air Optimization
Proper control of outside air provides necessary inside air changes for occupant comfort and health, minimizes energy costs by space pre-conditioning, allows for enthalpy-based free cooling, and reduces the use of outside air when it is not needed.
Orchestrating the operation of building systems, so that equipment works together, saves energy and improves comfort. Individual control systems that are not centrally monitored and coordinated can fight each other or malfunction, causing comfort problems and wasting considerable energy. BACnet based BAS can interface to existing or planned systems so that the building will run smoothly and at peak efficiency without expensive duplication of controls or unnecessary complexity.
Simplifying facility operation and integrating data from various systems in a "seamless" manner is best accomplished with a graphical user interface. This eliminates the need to memorize commands or point numbers, and allows the operator to take a walking tour of the facility from the console. Existing systems can be easily upgraded to add this powerful operational tool. Point and click graphics empowers management by letting everyone see what is going on and taking the mystery out of proper operations.
Direct Digital Controls (DDC)
Upgrade older existing equipment to DDC to match new equipment functionality. These controllers come standard on most new mechanical equipment and are more reliable, require less maintenance, provide more sophisticated control, and are less expensive to purchase and operate.
Conventional controls, such as time clocks, are inaccurate and are typically setup to run equipment longer than the actual need. By automating this function with computerized controls, the computer can predict the optimum time to start/stop equipment and eliminate waste caused by excessive runtime.
HVAC equipment is typically sized to handle the building load under worst-case conditions. Most conventional controls are set up to meet these design criteria at all times.With the automation system, control set points and strategies can be adjusted to meet only the actual load, eliminating unnecessary waste.