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© 2002,
Architectural Energy Corporation.
All Rights Reserved.
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 Funded
by California Energy Commission's Public Interest Energy
Research (PIER) Program
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P2-7. Enabling
Tools > Background
Building automation and control systems are
a special niche in the broad spectrum of
distributed computing and control technology.
The features and capabilities of building
control systems change rapidly, driven to
a significant extent by new computing technology
developed for other applications with larger
commercial markets. The advances in building
automation technology have taken place for
a variety of building services including
heating, ventilating, and air conditioning
(HVAC) control systems, lighting control
systems, access control systems, and fire
detection systems. Adoption of the BACnet
standard communication protocol has made
it practical to integrate building control
products and systems made by different manufacturers.
In spite of these
advances in technology,
many building control
systems do not work
as intended. In some
cases they never
did
because the design,
installation, or
commissioning
were not done well.
In other cases, inadequate
maintenance has resulted
in a deterioration
of system performance
over time. Computer
hardware and software
problems sometimes
contribute to the
difficulties. Because
the
ability to interconnect
traditionally independent
systems in a building
is a recent development,
there is much that
the industry needs
to
learn about how to
best take advantage
of
this kind of integration.
Commissioning,
automated fault detection
and new approaches
to applying system
integration are all
areas
of active research.
However, it can be
difficult
to conduct this research
in actual buildings
because of the need
to maintain comfortable
and safe conditions
for the building
occupants.
To overcome the difficulty
of conducting
this kind of research
using real buildings
and outdoor weather
conditions, NIST has
developed tools that
emulate an entire building.
This enables building
systems research to
be conducted under
controlled, reproducible
conditions. This
project involves two enabling
tools that have been
developed to advance
these research efforts.
It focuses on the
use of these tools
to develop and test automated
fault detection and
diagnostic (FDD) technology
for HVAC systems.
The two enabling
tools are the Virtual Cybernetic
Building Testbed
(VCBT) and the FDD Test
Shell. The VCBT consists
of a variety of
simulation models
that together emulate the
characteristics and
performance of a cybernetic
building system.
The simulation models are
interfaced to real
state-of-the-art BACnet
speaking control
systems to provide a hybrid
software/hardware
testbed that can be used
to develop and evaluate
control strategies
and control products
that use the BACnet
communication protocol.
The FDD Test Shell
is a data-sharing
tool that was developed
as part of IEA Annex
34 to enable side-by-side
testing and comparison
of two or more FDD
tools and to support
the integration of information
from multiple FDD
tools. The objective of
the work presented
here was to evaluate the
effectiveness of
the FDD tools for a variety
of fault conditions
and a variety of weather
conditions.
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