Building Automation Systems(BAS)
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.
Coordinating
Equipment
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.
Graphical
Operation
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.
Tighter
Scheduling
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.
Smarter Control
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.
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