Building Services Engineering 5th Edition Handbook

Heating 111
be separate from the heat network, and space, cost and acoustic advantages could be gained
in comparison with individual systems. A higher standard of service should be available from
centralized services, with fewer breakdowns and closer control of pollution.
Building energy management systems
Computer-based remote control and continuous monitoring of energy-using systems, such as
heating, air conditioning, electrical power, lighting and transportation, provide a higher standard
of service than can be achieved manually (Fig. 4.31). The following types of control can
be used.
1. The programmable logic controller (PLC) is a dedicated microprocessor programmed to
operate a particular plant item such as a boiler, refrigeration compressor or passenger lift.
2. The energy management system (EMS) is a dedicated microprocessor that is linked to all the
energy- and power-using systems such as heating, air conditioning, electrical power, lighting,
lifts, diesel generators and air compressors. It may appear as a metal box on a wall of the
plant room, having numbered buttons and a single line of screen display for maintenance
staff to use for carrying out a limited range of routine changes. Such a unit may serve as an
outstation that is either intelligent, having its own microprocessor, or dumb, merely passing
data elsewhere.
Monitor
Communication cable
Computer
Keyboard
Mouse
Linked
computer
Printer
Junction box
Telephone Fax Modem
Telephone line
Remote
outstation
Temperature sensor
Pump
Local
outstation
Burner
Air damper
Outstation
4.31 Building energy management system.