7 Reasons Why a BMS isn’t an Energy Management System

People often ask us whether they can use a Building Management System (BMS) to collect energy meter data and act as an Energy Management System. In theory, this sounds like a good idea – install one system to control both energy use and collect energy data. In practice, it is anything but ideal.


Whether or not you choose to use ResourceKraft Advisor Energy Management System (EnMS), the lessons of the industry are to install an EnMS that is independent of your BMS, ensures data quality and system security and is ideally Cloud based. Best practice organisations like the UK Carbon Trust and the Irish Government’s Office of Public Works recommend the same.

It’s all about data integrity, essential to implementing credible energy management systems like ISO50001, Measurement and Verification to IPMVP and best utilising Ene 02 Energy monitoring under BREEAM.

Here’s why:
1) Fit for purpose
As opposed to EnMS, BMS are not designed with continuous meter monitoring in mind, and are typically not capable of storing large amounts of real-time and historic data.
BMS software is static in design, with limited and inflexible data analysis tools, unable to produce energy monitoring reports, turn energy information into financial information or provide management and operations staff with the energy related feature set. It lacks flexibility and becoming quickly obsolete. Conversely, Cloud EnMS systems are updated regularly and can be customised if required.

2) Data loss

The primary problem with using a BMS for Energy Management is data quality.
Data loss occurs:

  • Anytime there is a power dropout.
  • Anytime the device network is reconfigured.
  • Anytime there is maintenance on the BMS.
  • Anytime there is a change in outstation connections.
  • Many BMS are powered by or backed up to one local PC or server, and often can only store energy data for a number of weeks. When the power drops or the system crashes, recording stops and often historical data is lost. Data management and backups is your problem!

EnMS data loggers are designed to time stamp meter readings immediately and store the data securely in non-volatile memory, for months if necessary, ready to send to the Cloud where it is securely stored and backed up.

3) IT Network Problems
IT networks are one of the core causes of data errors, failures and loss. Modern IP based Building Management Systems are connected and run within an organisations internal IT architecture. Where an IT error occurs, the meters cannot be read until the fault is corrected. Resulting in meter data loss.

Using Canary data logger/gateways, months of storage ensures that meter data integrity is preserved and the option of GPRS/3G connectivity avoids IT networks altogether.

4) BMS System Errors
A BMS is a complicated system with a large number of inter-dependencies between schedules, equipment and machines. Adding another layer of machine to machine communication to a BMS creates another list of possible configuration failure, points and errors. All resulting in data loss.

5) Cost of Legacy BMS upgrade
This assumes the use of a modern IP-based BMS system. Legacy BMS often cannot acquire meter data adequately and need to be upgraded in order to do so. Upgrading a BMS is expensive, requiring significant and costly work and can take weeks if not months to complete.

The BMS does not work in isolation. Before deciding to upgrade a BMS, an organisation should monitor and analyse all of its lighting, heating, ventilation and air-conditioning systems to identify and prioritise based on Return on Investment, where the energy waste elimination opportunities are. A BMS operating well in its control function will not be one of those priorities.

6) Locked In
Most BMS companies place restrictions on the way data is collected, locking you into their proprietary systems This often means that an independent software programme cannot be used to verify the data received by the BMS. It means that organisations cannot use a 3rd party Energy Management software suite, which would provide many of energy analysis features that a BMS can’t. while denying you future access to open technologies and the advances of innovation and software.

7) Security
Upgrading to an IP-based Building Management System exposes an organisation to a number of security risks. When the environmental control systems of the building are connected to the internet they can become a target for militant, corporate or criminal hackers. Many government organisations, universities, hospitals and corporate institutions limit BMS to an analogue or silo system for this reason. The result – excluding access for operational and production management and staff to the energy management software. Thereby defeating one of the main purposes of an Energy Management System – engaging those who are actually using the energy in its management control – a requirement of ISO 50001 and the best practice approach of national energy agency management programmes – Energy Star, Carbon Trust, SEAI, etc.

It is a common misconception that BREEAM Ene 02 mandates BMS (BEMS) for metering – The core intent of issue Ene 02 is the monitoring of energy use, therefore if an alternative system can achieve this, it would be considered acceptable. Guidelines were updated recently to remove this confusion. (reference KBCN0149).
It is acceptable under BREEAM for sub-meters to connect (or have potential to connect) to automated meter readers (AMR’s) or similar systems, as an alternative to BEMS.

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