Now much expanded, it today covers almost 40
buildings and incorporates DUC:ar, plus PC-based operator interfaces.
Since the DDC controlled buildings are widely scattered – some being
literally miles apart – the controllers have been linked via modem to
One way the system has made large savings is
through effective time control of the HVAC plant.
Previously the plant was operated 24hrs a day, whereas now it is
automatically switched off overnight. (Outside occupancy the system
applies a fabric and frost protection setpoint and thus brings on the
heating if the temperature falls too low.)
Here, as elsewhere on the site, much energy had
also been wasted by controls not being adjusted to reflect seasonal
In many of the buildings, the controls were on winter settings all year
round and this led to overheating during warmer periods. The BMS has
eliminated such problems.
Changes to time, temperature and other settings are now carried out via
the system’s operator interfaces, all adjustments being password
Making changes to building occupancy time settings – to allow for public
holidays, overtime working and new working patterns – is quickly and
easily accomplished using the BMS supervisors’ calendars task.
Operation Staff, points out: "Being able to make adjustments remotely –
which would not have been possible had conventional timeclock controls
been fitted – is invaluable on a site of this size."
Just as important, in the opinion of Operation
Staff, is the facility for remote monitoring of the building services:
As well as immediately reporting plant alarms, the BMS is a very useful
tool for fault diagnosis, the cause of problems often being identified
from controller logged data that is viewable in graph form on the BMS.
It also warns of the need for plant maintenance, such as renewing AHU
filters. More importantly, monitoring by the system has greatly reduced
the need for our busy maintenance staff to make regular tours of
inspection of building plant rooms.
In addition to the substantial cuts in energy
consumption produced by the BMS, appreciable savings have also been made
through good ‘housekeeping’, the installation of new HVAC plant and the
widespread use of CO2-demand control.
Since the first DDC-controller went into action,
the BMS has never really stopped growing.
AC have thus had a near permanent presence at S1, with as many as 3
engineers on site during peak periods of work.
Further growth of the system is planned and it may eventually cover the