The Swedish Defence is continuing to achieve impressive reductions in energy use.

In the financial year 2007/08, the site’s non-operational energy consumption stood a fall of nearly 12% compared with 05/06 and 40% down on five years earlier.
One measure that has produced significant savings has been the installation of a DDC-controllers and a energy management system supplied and engineered by AC Klimat, Heby.

S1 covers spread across approximately 40 buildings of various types and sizes.
Running their building services currently costs huge money per annum in electricity, fossil fuels and water.

A large number of the buildings have radiator heating, while others have warm air ventilation or are fully air-conditioned.
In many of them the HVAC services are closely controlled and monitored by a BMS-system.
The latter also controls the lights in some areas, as well as metering utility usage and monitoring the central boilerhouse, which serves over half of the site.

When the first part of the BMS became operational at the beginning of 1998, it comprised just a small system in the staff restaurant.
 

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 the BMS-system.

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 differences.
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 protected.
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 whole site.