Specifications

83Environmental Automation
Introduction
Environmental automation refers to the
automated controls for systems that
regulate the environmental conditions
of the interiors of all kinds of buildings.
Systems for commercial buildings—
oce buildings, skyscrapers, hospitals,
etc.—are called building automation
systems (BASs) or building management
systems (BMSs). Systems for residential
buildings—homes and apartments—
are called home automation systems
(HASs). There are similarities between
BASs and HASs, but there are also
signicant dierences. BASs are often
much more complex and often control
systems do not exist at all in HASs.
HASs control some items that are not
found in BASs, but there is overlap.
In this section, we survey the equipment
found in buildings and briey discuss
their operation, sensors needed, and
the signaling and control aspects of
automating their operation. There
is signicant overlap with content
provided elsewhere in this guide, so
where appropriate the reader will be
referred to other sections or chapters.
At rst one might think that the
environment for this equipment is not
as harsh and its operation not as critical
as that in a factory process-control
environment, but one need only realize
that this equipment is just as likely to be
installed in a hospital as in a shopping
mall. With patients’ lives dependent on
proper room conditions, power, and
water supply for their life-sustaining
needs, these systems must be very
reliable. Furthermore, in large buildings,
these systems are likewise large and
require large amounts of energy to run.
For example, large air conditioning
systems can draw huge amounts of
power, much more than in some smaller
factories, so large switching load
transients are common. Air conditioning
systems can build up static electricity
due to low humidity airows, so ESD
strikes are not uncommon. One can see
that robustness, reliability, protection
from fault conditions, surge handling
capability, and ESD protection are
just as important in equipment used
for environmental automation as
they are in factory automation.
According to The Oce of Energy
Eciency and Renewable Energy
(EERE), in its Buildings Energy Data
Book, between 2002 and 2008 40% of
U.S. primary energy was consumed
in the buildings sector. The industrial
sector was responsible for 32% and the
transportation sector 28% of the total.
Of the 40% consumed in the buildings
sector, homes accounted for 54% and
commercial buildings accounted for 46%.
As for energy sources, 76% came from
fossil fuels, 15% from nuclear generation,
and 8% from renewable. Eciency
improvements and usage reductions
in primary energy consumption
can lead to substantial savings.
Home Automation
Systems (HASs)
The low-cost personal computer, Internet,
and a variety of radio technologies
available to transfer digital data at
high speeds have enabled a market for
home computerized appliances and
home control systems. Monitoring and
control can now be done automatically
and remotely to enhance security,
convenience, comfort, ambience, and
energy conservation of the modern
household.
With a home-based local area network
using Ethernet and open-source
embedded operating systems like
Linux
®
, the following systems can
all be tied into the HAS: heating,
ventilation, air conditioning (HVAC),
major appliances, security systems,
lighting, home entertainment systems,
irrigation systems, and even pet
feeding and domestic robots. Low-
cost WAN technology like digital
cable and DSL, initially provided
to deliver entertainment, can now
be used to provide monitoring,
remote control, and automation of
home environments for security,
energy savings, and convenience.
While the optimum time to install an
HAS is during new construction when
the walls are exposed, it is becoming
easier to retrot existing homes with
automation systems using wireless
technologies. One example bridges
cabled Ethernet to Wi-Fi
®
and transmits
data through powerline communications
such as HomePlug
®
devices.
Overview
U.S. ENERGY
CONSUMPTION
U.S. BUILDING
SECTOR
RENEWABLES
8%
TRANSPORTATION
28%
PETROLEUM
6%
COMMERCIAL 18%
RESIDENTIAL 22%
INDUSTRIAL 32%
COAL 38%
NATURAL GAS 33%
NUCLEAR 15%
WORLD ENERGY
CONSUMPTION
RUSSIA
6%
OECD
EUROPE
16%
CHINA
17%
U.S.
20%
OTHER
40%
Estimated U.S. energy use between 2002 and 2008 (Source: Buildings Energy Data Book from The Office of Energy Efficiency and
Renewable Energy (EERE)).