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Building management systems

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A building management system (BMS) provides automated precision to optimise the energy efficiency and occupant comfort of one or more buildings from a single digital interface.

The system will monitor and control a building’s electrical and mechanical services, such as HVAC and lighting. It can also incorporate wider building services such as security, access control, elevator and safety systems.

Depending on specific application and configuration, a BMS may be known as a:

  • building automation systems (BAS)
  • building management and control system (BMCS)
  • building energy management system (BEMS).

A BMS can be procured as a complete, engineered package or implemented to integrate existing systems. BMS applications are based on open communications protocols and are web-enabled, for the integration of systems from multiple vendors.

Benefits of a BMS

Compared with separate control systems, a BMS offers centralised control, flexibility, interactivity and feedback.

A new BMS should be an essential consideration of any major building fit-out or plant upgrade. A BMS older than 10 years is likely to benefit from an upgrade or replacement.

Reasons to consider upgrading include:

  • reliability issues
  • poor condition of components
  • lack of web compatibility
  • difficulty with incorporating new equipment and sensor
  • ability to perform monitoring and reporting.

Following installation, a BMS should be closely monitored and fine-tuned for at least 12 months. The system can initially perform badly due to poor commissioning. Control loop tuning will ensure equipment operates in a stable, predictable and repeatable manner.

Specifications should include:

  • a requirement for the BMS contractor to regularly run diagnostics
  • assessment of energy-use trends
  • reporting against targeted NABERS ratings.

Other benefits associated with a BMS are outlined below.

Comprehensive control and optimisation

BMS allows control and optimisation of equipment cycles, and can be implemented with algorithms focused on energy efficiency.

The following energy saving strategies can be enabled:

  • Accurate control of a range of comfort conditions, including seasonal temperature adjustments.
  • Precise start-up and run times.
  • Economy cycle control including CO2 occupancy control.
  • Removing overlap between systems, especially heating and cooling equipment.
  • Adjusting for seasonal conditions, including variable plant sequence selection.
  • Air pressure and coolant temperature control.

To get the most out of a BMS, correct location and calibration of sensors is crucial. This ensures the BMS is responding to accurate readings at all times.

While sensors don’t usually suffer accuracy drift over time, a baseline error of up to one degree can occur and must be offset. Greater inaccuracies can occur due to sensors placed at the wrong height or near heat sources.

Ability to maintain tuning

A BMS helps maintain a building’s HVAC tuning over extended timeframes. It’s common for buildings using stand-alone controls to deviate from their original, optimised settings over time. A BMS can respond to drift in real time, helping to maintain optimum tuning all the time.

BMS can also highlight systemic faults associated with excessive energy use. It can identify wasteful patterns, such as equipment left on when not needed.

Time savings

Automation takes pressure off managers and staff to monitor data and adjust settings.

The BMS single-user interface also saves time by bringing all relevant information and controls together in one place. Interfaces range from basic dashboards through to full graphic workstations. A BMS can quickly translate real-time data into useful business information, assisting rapid decision-making.

Lower maintenance costs

A BMS enables early identification of equipment failure. Over time, buildings can become less efficient as operational patterns change and equipment performance declines. A BMS can implement diagnostics for most HVAC components, and detect when a component is starting to fail. Operators can be alerted to commence preventative maintenance.

Improved occupant comfort

A BMS allows real-time monitoring and optimisation of occupant comfort. It accounts for factors such as temperature, humidity, air quality and flow. A BMS can also provide notification and rectification of faults before comfort is diminished.

Performance management and reporting

A BMS has performance management and reporting capabilities, to meet energy consumption and star rating targets. In high-performing buildings, a good NABERS energy rating is crucial to rental income and asset value.

A BMS supports targets by:

  • diagnosing performance drops in a timely fashion
  • measuring against load-profile targets and making adjustments
  • recording trend data, including separation into tenant and base building loads
  • displaying dashboard-style feedback on demand and consumption.

Innovations

Affordable wireless networks

Historically, the expense of a BMS has limited its application to large commercial buildings. Equipment such as controls and sensors have come down in price. Wireless technology is increasingly commonplace, making BMS installation easier and more affordable.

Opportunities to implement a BMS have been enhanced through internet connectivity. Communication between devices or complete systems over a data network is replacing hard-wired connections. Recent developments in wireless energy harvesting is enabling a new generation of sensors that gain energy from ambient sources.

Grid responsive demand management

The nature of the grid is changing, with increasing need for businesses to tailor their load in response to price signals and shortages during severe weather. In addition, building owners are installing more grid-connected generation and storage on their premises.

BMS are being integrated with software-based, grid-responsive demand management systems or specialised energy management systems (EMS). These innovations allow for optimisation of energy consumption, generation, export and storage.

Predictive capabilities

A BMS can reduce maximum demand charges, which make up a sizeable portion of many business’ energy bills. A BMS can anticipate high building loads and allow appropriate adjustments to avoid maximum demand threshold levels.

A web-enabled BMS can anticipate favourable or extreme weather conditions and adjust HVAC sequences for the most efficient outcome. For example, if the BMS anticipates a hotter than normal day, it can automatically pre-cool the building to take advantage of off-peak energy.

Integration with broader business systems

The flexibility and cross-compatibility of BMS components allows multiple aspects of a business to be coordinated more effectively. For example, a BMS can feed into accounting and resource planning, or interface with entire facility management systems.

Integration with building information modelling

Building information modelling (BIM) is a 3D imaging process used by architects, engineers, and construction professionals to collaboratively plan, design, construct, and manage buildings.

Integrating a BMS with a BIM allows a proposed design to be simulated and refined prior to construction.

Read more

A primer on organizational use of energy management and Information Systems (PDF 856KB) US Department of Energy

BMS - Advanced management and improvement opportunities (PDF 2MB) City of Melbourne

Case study - Using on-bill financing to finance a new building management system (PDF 175KB) NSW Government