Building Management Systems VS Energy Management Systems

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 Advisor: Energy Analytics, we advise you to install an Energy Management System that is independent of your BMS. Best practice organisations like the UK Carbon Trust and the Irish Government’s Office of Public Works recommend the same.

Here’s why:

1) Not fit for purpose

BMS are not designed with metering and monitoring in mind, and are not capable of storing large amounts of real-time and historic data. BMS are not designed as a Data Analysis tool, they cannot produce energy monitoring reports, turn energy information into financial information or provide management and operations staff with the energy related feature set.

2) Data loss

The primary problem with using a BMS for Energy Management is that data quality averages at 60%.Data loss occurs:Anytime there is a power dropout. Anytime the IT network is reconfigured. Anytime there is maintenance on the BMS. Anytime there is a change to the Modbus connection. Many BMS can only store energy data for 2-6 weeks. Many BMS are powered by or backed up to one local PC or server, and when the power drops or machines are broken historical data is lost.

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. A firewall environment causes problems not only for the BMS itself, but also for Energy Metering. All meters need to be connected via Ethernet. This vastly increases the cost as fibre optic cables need to be installed in remote parts of the building.

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.

5) Cost of Legacy

BMS upgrade This assumes the use of a modern IP-based BMS system. Legacy BMS cannot acquire meter data and need to be upgraded at some cost in order to do so. Upgrading a BMS is expensive, requires civil work and can take weeks if not months to complete.

6) Measure & Verify

In order to forecast the savings, ROI and payback period of a capital project like upgrading a BMS, an organisation first needs to understand its baseline. Without installing an Energy Management System, organisations are resigned to comparing utility bills to get this baseline.

Furthermore a 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 where the energy waste elimination opportunities are.

7) Locked In

Finally BMS companies place restrictions on the data that is collected, denying access to open source technologies and software. This means that an independent software programme cannot be used to verify the data received by the BMS. It also 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.

One more for good measure…
8) Security

Upgrading to an IP-based Building Management System exposes an organisation to a number of security risks. As the environmental systems of the building are connected to the internet they can become a target for militant, student or corporate hackers. Many government organisations, universities, hospitals and corporate institutions limit BMS to an analogue or siloed system for this reason.

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