(This is a generic name referred to as a BMS. These systems can also be called an Energy Management Control System or a Building Energy Control System or Direct Digital Controls DDC) A Building Management System (BMS) is a central computerised system for managing and operating systems within a building. A BMS usually incorporates controls for air conditioning, for energy management, maintenance management, security, access and fire systems. A BMS is an essential tool in tuning the operation of any building and, just like a well tuned car, a well tuned building not only runs more efficiently, it generally provides better performance. This ensures that operating costs are minimised and occupants are more comfortable. To manage energy use, it can monitor various parameters in the building such as temperature, humidity, energy usage and occupancy patterns. By doing so, services such as air conditioning, ventilation and heating, lift services, hot water systems and lighting are able to be controlled in ways that minimise energy use while optimising comfort and functionality.

Use a Building Management System to gain tighter control over your building and cut total energy costs by up to 30%.

This section specifically looks at the use of a BMS as a tool for energy management.

Taking Action Choose the applicable scenario: 1. Using existing controls more effectively: Is the potential of the BMS being maximised? Info: Just utilising the existing controls (after ensuring they work properly) to manage the air conditioning system and lighting can deliver worthwhile savings at little cost. These savings can then be invested in upgrading control systems to those that offer greater flexibility of control. Action: Review Installing a new Building Management System that follows to understand the three main functions and full potential of a BMS. Identify the brand of your BMS and contact the relevant supplier (or an energy management consultant) to clarify its capabilities, check that it is functioning correctly, and set it up for maximum savings.

Ensure you are not heating and cooling your office space at the same time. Reheating cooled air is the single most wasteful use of energy. Ensure the BMS turns off lights at night when no one is occupying the building. Adjust temperature set points up by 1 degree in summer and down by one degree in winter, through the BMS. Check on/off times – does your plant start up a long time before occupancy? If so, change it.

Are there complaints about comfort?

• Info:
  • Complaints about comfort conditions in your building might indicate that temperature sensors are badly located causing poor control, or the system could be oscillating between heating and cooling. This means that energy is being used to cool air in an area down to a low temperature, then more energy is being used to heat this cool air back up to a required temperature.
• Action:
  • As the refrigeration plant is one of the larger loads usually encountered in a building, make a trend of your cooling load (either comparing your chilled water leaving and chilled water return temperatures), or even just compare chiller on/off times with outside air temperature. Include boiler on/off times to ensure that you don't have cooling fighting heating as described above.
  • If your building has more than one chiller, check chiller schedules and operation. Refine the BMS so that it can select the most efficient chiller or combination of chillers for the seasonal duty required. Also make sure chillers are not starting and stopping too often.
  • Adjust chilled water leaving temperature set points to match the building load.
  • If you have variable speed drives on pumps or fans, make sure these are stable in operation.
  • Adjust condenser water and condensing temperature set points up to improve chiller efficiency.

Can you gain tighter control of energy use with the BMS?

• Info:
  • Savings can be made simply by adding or changing some of the set points, which are the temperatures or times that the BMS is programmed to activate or shutdown systems within the building. For instance, times for air-conditioning and lights to switch off, and the temperature of the air conditioning. It is important to ensure your BMS is being used properly and is maintained. For example, the BMS manager must be able to calibrate outside air economy cycles (if they exist and are operational) regularly to ensure the BMS is not allowing excess outside air into the building.
• Action:
  • Trend graphs are the easiest tools to tune your building so make sure you know how to set up trends for your important monitoring points. For instance, look at your overall energy usage. Just analysing this graph regularly can help you to understand how energy is being used in your building. You can then use the BMS to manage peak electricity demand by switching off non-essential loads when demand is high. Since electricity contracts include separate demand charges, which can comprise up to half of total electricity bills, doing this can generate large savings.
  • If you are finding it difficult to analyse what is happening on these trends, call in your BMS supplier or a consultant to help you. Some companies offer off site monitoring and analysis to help you tune your building throughout the year.
  • Set up some seasonal checklists to ensure that equipment is ready for service at the start of each season. Even if everything operated perfectly last summer there have probably been some changes in the building that will have it operating differently this time. Tuning needs to occur throughout the year as seasonal changes make a big difference to how a building operates.

2.Installing a new Building Management System

• Each building is different and your BMS will depend on many variables, so before installing the system seek advice from a number of suppliers or an energy consultant. An energy consultant should help you to decide which applications you want to control, e.g. air-conditioning, lifts and lights or just air-conditioning.
• Operators need to be trained to use the new system so that maximum benefit can be obtained.
• When considering a new installation, it is important to understand the three main functions of a BMS:

A. Monitoring

To minimise energy consumption, energy use should be monitored on a continual basis and a good BMS makes this task very simple. Using a BMS, the following can be monitored:

• Equipment and plant faults
• Energy consumption by different building operations
• The effect on energy use of improving equipment operation. For example, energy savings from a lighting upgrade can be monitored with the BMS
• Electricity, gas and water use
• Building temperatures and air quality
• Operating times
• Dirty filters
• Occupancy patterns
• Alarms to highlight out of normal system operation.

B. Controlling

The BMS is interfaced with building controls which can automatically:

• Control chilled water temperature (in cooling coils for air conditioning) to reduce energy use
• Turn off loads like chilled water pumps when not required
• Control Variable Speed Drives to reduce chilled water pump energy or fan energy
• Turn off lights and lifts when not in use
• Receive data from the peripheral controls, such as occupancy sensors, and relay this information to the system control level
• Allow the use of economy cycles using outside air
• Some BMS offer standard software to carry out sophisticated energy management routines such as:
• Optimum Start
• Night Purge
• Economy Cycle
• Ventilation Control

C. Reporting

• Reports can be generated using tables and graphs, showing trends that indicate whether the performance of the building is deviating from what is expected and which actions are required to correct the deviation.
• Data logging can define temperature and conditions where leasing disputes occur.

A BMS is an important part of a building. Use it to understand how your building operates and you will profit.