This paper gives the end user guidance on the benefits and issues
surrounding interoperability and a brief review of the history and
the current state of technology for Energy Management Systems. Emphasis
is placed on how to go about getting the right system that will generate
savings and reduce installation and maintenance costs.
The BACnet standard is relatively new and just now beginning to
be specified and installed. This paper is written at a time before
BACnet has been fully integrated into the industry and extensively
field proven, although major installations (1) have been successfully
Since an Energy Management Decision is a long term commitment,
it is important for the end user to understand the impact of BACnet
on their current and future purchases. Otherwise, you may be specifying
and installing an Energy Management System destined for premature
WHY SHOULD USERS CARE?
Cost and flexibility is why. Up until recently, each and every supplier
of Energy Management Systems had only proprietary designs. If you
wanted modifications or additions, you would generally only have
one choice, to go back to the original supplier and pay their prices.
Fortunately, efforts have been underway to allow one supplier's
equipment to "talk" to another's via the BACnet standard. This will
allow end users the flexibility to purchase equipment from different
suppliers to get an optimum system at the least cost.
A BRIEF HISTORY OF ENERGY MANAGEMENT SYSTEMS
Automatic controls were developed in the late 1800's and a workable
night thermostat was developed in the very early 1900's.
Not until the 1970's, with multiple energy crises, and increasing
costs, did the idea of conserving energy become really important
to building owners. The most important new technology was the advent
of the computerized Energy Management System. These early systems
provided centralized control, unattended, with electronic accuracy.
However, these early systems tended to be bulky, not user friendly,
unreliable, and very expensive to install and upgrade. The earliest
Energy Management Systems were installed in the early 70's and utilized
small "mainframe" style computers that were costly, bulky and hard
to program. The term "user friendly" had yet to be invented. The
next generation (late 70's) graduated to a minicomputer or a vendor's
proprietary CPU design.
During the late 1980's and 1990's, technology changed the face
of Energy Management. The personal computer (PC) and increasing
computer literacy of the general population was responsible for
improving the performance of Energy Management Systems. The PC brought
with it an easy to use graphical interface that improved the effectiveness
of the operator interface. Now, the operator had a tool to use in
understanding and controlling energy systems.
Again, going back to the earliest Energy Management Systems, all
external devices were hard wired back to the computer. Then a distributed
format evolved utilizing multiplexed signals over a common wire
or over the electrical distribution system (power line carrier).
The multiplex system did a lot to reduce the cost of wiring input/output
devices. Now we have moved to the beginning stages of true interoperability
between systems and components. Although they are not yet fully
"plug-and-play" compatible, these early systems do allow for the
mixing of some components today.
And the world of interoperability is here, today. There are over
thirty suppliers of controls and manufacturers of HVAC, lighting,
fire alarm, security and electrical systems that have or are developing
capabilities for interoperability using the BACnet standards.
BACnet BASICS ::
The BACnet Standard 135-1995 (2) was developed by the American Society
of Heating, Refrigeration and Air-conditioning Engineers, Inc. (ASHRAE)
to promote a common methodology to allow devices from different
vendors to communicate with each other. BACnet compatible devices
are available from a variety of controls' vendors and equipment
LonWork's LonTalk is a subset of the BACnet standard. LonWorks
is often implemented in either a standalone fashion for smaller
systems or as the preferred communications method for unitary controllers
as a subset of a BACnet installation.
You might think of BACnet as a standard language for passing information
back and forth amongst various suppliers' devices. For example,
this could be a command to turn on a fan or an outside temperature
reading being shared with multiple controllers.
BACnet ADVANTAGES FOR THE END USER ::
Capital Cost Reductions-Initial Installation
The biggest advantage for the end user will be lower prices due
to competition from multiple vendors. BACnet also allows equipment
suppliers to design dedicated controls into their equipment at the
factory. Then, when the equipment arrives in the field, it's a simple
matter of connecting a control cable and the Energy Management System
will be able to talk to the equipment and vice versa. The labor
costs of a field installed Energy Management System are normally
more than 50% of the total cost, the efficiency of factory installed
controllers provides for a lower total cost.
Capital Cost Reductions-Modifications, Upgrades and Expansions
An even greater reduction in cost will occur whenever an existing
system is modified, upgraded or expanded. Until BACnet, I often
referred to the relationship between the Energy Management System
supplier and the owner as a marriage. Like a marriage, one has to
choose their partner with care because a divorce is painful and
expensive. With the suppliers each having different protocols, the
ability to change or upgrade the system was nearly impossible except
from the original supplier. The only other alternative was to (remove
and replace) divorce the original supplier with a new one. Under
this scenario, the cost for a divorce would be prohibitive and the
original supplier has little incentive to be cost competitive.
Operating Cost Reductions
Besides the cost of any major modification, upgrade or expansion,
the cost for maintenance and repair (M&R) services on a BACnet
Energy Management System, will be less. Maintenance costs typically
range from as low as 5% of the original installed cost per year
up to as high as 15%. The cost varies widely depending upon the
local market and the extent of services contracted. Over the life
of the system M&R costs could exceed the installed cost. With
BACnet implemented, more suppliers could provide M&R services
on the Energy Management System and use their own or other's parts
for replacement. This will result in lower costs for M&R services.
The Best Technology
In my experience, all of the Energy Management System suppliers
have strengths and weaknesses. One vendor may make a great humidity
sensor and another might have the best VAV controller in the world.
With BACnet, the system installer has the flexibility to pick and
choose the components that are optimum for the job.
HOW TO BUY COST-EFFECTIVE ENERGY MANAGEMENT
In my experience, Energy Management Systems continue to be one of
the best investments in energy management (after lighting) for controlling
operating costs and improving comfort and reliability. However,
unless the system is designed, installed, programmed and operated
correctly, the results will be less than desired. This is true for
all Energy Management Systems and even more so for future systems
if they are to take advantage of the move to more open architectures.
TIPS FOR BUYING COST-EFFECTIVE ENERGY MANAGEMENT
Educate yourself. Knowledge is the key to success for effective
Energy Management Systems. Sources include ASHRAE, The Association
of Energy Engineers, publications like Energy Users News, technical
conferences, the Internet, Energy Management System suppliers and
Talk to other end users about their experiences. They've been there,
done that. Find out what their experiences have been with Energy
Management System suppliers and the energy management strategies
that work for your type of operation and buildings. The best bet
is to actually go visit the sites and talk to the operators directly.
Interview prospective suppliers. Here you are not only trying to
learn about their technology, but their ability to support your
system in the long run.
Prepare a performance-based specification. This specification should
include all the features desired including BACnet compatibility.
The energy management strategies being implemented need to be completely
identified if the savings are to accrue. The specification should
be specific enough to cover the performance of the system and general
enough to allow multiple vendors to present competitive proposals.
Hire a consultant. If you feel you do not have the time or expertise
to design, install, program and operate an Energy Management System,
a consultant might be the right choice for you. However, insist
that the consultant has not only experience in designing Energy
Management Systems, but also has hands on field experience in supervising
installation, programming and operations. I have seen too many Energy
Management Systems that were designed by consultants without field
experience that did not meet expectations.
Operations is the key to a successful Energy Management System.
The designer, installer and programmer of the Energy Management
System get to go home after it is turned over to the owner. The
local operator is often left with a complicated system without adequate
input and training. From that day on, the operator makes the biggest
difference between a "time clock" and an effective Energy Management
System. To achieve the desired savings and in my experience generate
even greater savings in the future: 1) Have the operator be involved
in the design and selection process, 2) provide training during
and after installation and 3) have a program of ongoing support,
optimization and training in place.
THE FUTURE ::
I have been following and writing about the future of Energy Management
Systems since 1991 with the papers "Energy Management 2001" and
"Energy Management 2005". In 1991, interoperability was just a desire
that end users had. With BACnet, that dream has started to come
true. In just a few more years, the end user will be able to plug
in components just like they can today when matching stereo, computer
and telephone components.
UTILITY DEREGULALTION AND INTEROPERABILITY
With the passage of the Energy Policy Act of 1992, the process of
deregulating the electric industry was begun. Deregulation will
bring unprecedented changes to the way that utilities are purchased,
used and controlled. The number and complexity of utility bills
will multiply. Real Time Pricing tarriffs and other time sensitive
rates will challenge the abilities of an Energy Management System
to control loads in an effective manner to reduce costs. In addition,
the rate of change in utility metering, billing methods and control
is increasing. It is important that any Energy Management System
being specified today have the ability to handle sophisticated energy
management strategies and be able to be easily reconfigured to meet
changing needs. That is why it is important that any new Energy
Management System be specified with BACnet compatibility.
The evolution of the Energy Management System from the inflexible,
proprietary system of the 70's to the easy to understand open architecture
has occurred over the past 25 years. BACnet's development and further
acceptance are allowing end users to obtain better and more cost
effective systems. An end user can obtain systems that work and
produce the savings desired by following the Tips for Buying Cost
Effective Energy Management Systems presented in this paper and
spending some time getting educated on Energy Management Systems
in general and BACnet specifically.
NOTES AND REFERENCES ::
1. "450 Golden Gate Project, BACnet's First Large-Scale Test",
Martin A. Applebaum PE and Steven T. Bushby. July, 1998 ASHRAE Journal
2. ASHRAE Standard 135-1995, "BACnet A Data Communication Protocol
for Building Automation and Control Networks"
3. "Energy Management 2001", "Energy Management 2005" and "The
Proper Selection, Care and Feeding of an Energy Management System",
George R Owens PE CEM, Energy and Engineering Solutions, Inc. These
papers can be viewed here.
BACnet is a trademark of ASHRAE
LonWorks and LonTalk are trademarks of Echelon Corporation
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ABOUT THE AUTHOR ::
George R Owens PE CEM - Experience includes over 21 years in Energy
Management in the commercial sector with an additional 9 years of
Electrical Engineering in Industry. He is a registered Professional
Engineer in five states, Certified Energy Manager, recipient of
Energy Awards, publisher and presenter of energy articles, author
of book chapters, past seminar instructor with universities' Energy
Programs, quoted in newspapers, radio, television and magazines
and has served as an advisor to the utility industry on DSM Programs.
The subjects of his presentations have covered Utility Deregulation,
Energy Conservation, O&M, Commissioning, and the Future of Energy
George Owens has membership in several professional organizations
(AEE, ASHRAE, IEEE, IES, NETA), where he has held committee and
officer positions. He is a recipient of the Association of Energy
Engineers's International Energy Manager of the Year and was inducted
into the Energy Managers Hall of Fame.
1997 - Present: President - Energy and Engineering Solutions, Inc.,
a firm that provides cost-effective solutions to the Commercial,
Real Estate and Institutional sectors with a focus on Energy Management.
1981 -1997: Director of Engineering - Responsible for an annual
$85 million utility budget for The Rouse Company which owns, develops
and/or manages over 75 shopping centers and 120 office buildings
throughout the United States and Canada with 57 million square feet
1977 - 1981: Energy Engineer - Federated Department Stores, Shillito's
Division. Developed and implemented the Energy Management Program.
1968 - 1977: Electrical Engineer - Proctor and Gamble Company,
Charmin Paper Division.
To send comments to George R. Owens, click here:
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