Intelligent buildings: the network's already in place
Richard Hipkiss believes Ethernet holds the key to the convergence of
building management systems
The growth of Ethernet in industrial control networks continues unabated,
so it is not surprising to find the case is even more true of controls
within the built environment, where the ubiquitous open standard already
flourishes. A modern building is rather like a process plant because it
is now likely to have a variety of systems to control - lighting,
heating, ventilating and air conditioning equipment, lifts or escalators,
security and access systems, electric window controls, IT systems,
telecommunications and so on. The greater the requirement for centralised
control, the greater the problems of incompatibility. Far better to aim
for convergence rather than compatibility - since convergence is
attainable today, whereas compatibility may never be achieved.
The proliferation of proprietary and so-called 'open' fieldbuses has done
nothing to those seeking the holy grail of compatibility. In the
manufacturing sector this has been problematic and occasionally
restrictive. Fieldbus options developed for industry are now finding
their way into the built environment. As ac drives, PLCs, HMIs and other
industrial equipment finds its way into buildings, the communications
options logically follow. In buildings, however, there are other
networking standards to contend with, including LONworks, DALI (Digital
Addressable Lighting Interface), DSI, Digital, Analogue and so on.
The overwhelming majority of building automation vendors have entered the
market from a single platform of expertise, be it lighting, security or
HVAC. In truth, these vendors may have excellent solutions within their
specific competencies, but these compromise all other areas of the
automation system. Finding common ground is impossible, but the openness
of Ethernet and the fact that just about every network has interfaces for
it, provides a link to enable sufficient convergence to enable
centralised control. For example, variable speed drives used typically in
HVAC installations will need to be remotely controlled as ambient
conditions change or the needs of the building occupants vary. An
Ethernet connection from the drive to the building management system can
achieve this.
The concept of intelligent buildings using building management systems is
either addressed too late or not considered at all because of the cost
implications. This is a ludicrous situation, since there are remarkable
savings that can be made if data networks are considered early enough.
The overwhelming majority of electrical and mechanical contractors
complain that they are the ones faced with installing cables and
equipment for which no provision has been made. It is even worse for the
voice and data installers and worse still for the building management
system providers. If all the building control networks ran on Ethernet,
it is perfectly reasonable to pull those cables through a building at the
same time as the electrical mains are being installed. The time and cost
savings are considerable.
Another overlooked factor is that just because a building is intelligent,
it doesn't imply it is energy efficient. Few building management systems
address energy consumption - especially at the building design stage. The
fitting of variable speed drives on continuous duty applications such as
fans and pumps is laudable, but rarely are these installations completed
in the most effective manner. Variable speed drives don't save energy or
money unless they are controlled in a manner calculated to maximise the
savings. To do this requires greater intelligence, including localised
energy monitoring.
Irrespective of the building to be built or managed, there is a need for
solutions to the problem of controlling energy consumption. This holds
true for all types of buildings, in the industrial, residential or
service sectors. Before designing or upgrading a building, and in
particular its electrical installations, it is essential: to study its
energy needs and the available energy sources; to find the best balance
between management systems, distribution networks and consumer equipment;
to take account of operational requirements.
It is worth noting that in hot periods, the air conditioning and
ventilation equipment in a typical commercial building may account for
65% of its total energy usage!
Richard Hipkiss is with Schneider Electric's T-BIS business unit
Schneider Electric started working on an Ethernet based network for
industrial control in the mid-1990s when it developed web based
technology called Transparent, writes Les Hunt. Now known as Transparent
Ready, the enabling software and firmware is built into most of the
company's Merlin Gerin, Square D and Telemecanique branded equipment,
including electrical distribution equipment and switchgear, PLCs and
HMIs, power monitors and, of course, ac drives. The equipment hangs
directly on Ethernet and each device can be directly addressed using a
standard browser. And since each piece of equipment has its own embedded
web server, it can be viewed using a TCP/IP address.
Ethernet based power and control solutions can help streamline building
management and increase operating efficiency in many ways, as well as
reducing engineering costs. Schneider recently consolidated its approach
to the building management systems market by launching the Transparent
Building Integrated Systems (T-BIS) business. A 28-strong team is now
able to concentrate its efforts on the sector, drawing on Schneider's
broad range of Transparent Ready enabled products, including the Altivar
ac drives range and PowerLogic energy management software.