How to successfully integrate a BMS and an EMS
How to successfully integrate a building management system and an energy management system is shared by NIGEL WRAIGHT, manager at Thomas Wraight Asset Management, Facility and Property Services.
Facilities managers are faced with managing greater volumes of technology in their buildings as the pressure increases for buildings to perform with improved sustainability. More technology means more computers on a desk, or does it?
‘More black boxes to understand and more vendors to be held captive to’ is a negative view and it’s held by many who are at the helm of driving a building. However, things are not that bad. In fact, it is better now than it ever was.
Why? Because there is a greater number of vendors, a greater number of systems and a more competitive marketplace – not just for your dollar, but also to provide a service that ensures a ‘cradle to grave’ client.
EFFECTIVE SYSTEM INTEGRATION
Integration of systems is not an expensive task and is the key to optimising existing and future technology to deliver results. I define results as reducing manual data handling and making building management easier, effective and more proactive. The key word here is ‘effective’, as you can integrate a huge building system and it does nothing. Integration completed effectively and in consultation with the facilities manager can save time, money and a lot of stress.
Integration is only limited by our imagination in solving problems. To demonstrate, I’ll use a few examples (all of these are considered for existing operational buildings).
EMSs AND BMSs
Should we add an additional energy management system (EMS) over and above the building management system (BMS)? Should we extend the existing BMS to include an EMS? Should we replace the BMS and refurbish the system with a combined BMS and EMS? Technically, you should get the same results in terms of monitoring your energy, but there are some hidden gems of economies in the different methods.
An additional EMS
There are several reasons for this consideration, such as:
- there is no existing BMS
- the existing BMS is obsolete and using a proprietary protocol, and
- the existing BMS is a ‘captive single vendor system’.
Eliminating these reasons and integrating a combined EMS and BMS whole building system means a greater capital expense than just an EMS and this capital may not be available for some time. There is a way to help and assist with ‘future proofing’ an EMS when the capital becomes available.
Any EMS considered should be an open protocol system. An open system will mean the EMS can communicate with a BMS without the need for a gateway (gateways are often a source of communication errors – don’t go there).
Integration between two systems that both have the same open protocol is seamless and effective as the BMS can ‘talk to’ the EMS and vice versa.
Beware of ‘proprietary open’ systems (‘vendor1 Bacnet’, ‘vendor2Bacnet’ or ‘Vensor1 Lon’ for example). They comply with the specification, but they do not ‘like’ other vendors and will not communicate with them.
Integrating an existing BMS and an EMS
For this discussion, we assume the existing BMS (or EMS) is an open protocol and the integration is straightforward in terms of extending the existing BMS network to include energy monitoring devices. This works well if all the devices are of same protocol – that is, all devices are available in the same protocol and are all competitively priced.
But, this doesn’t happen. Vendors of energy monitoring devices have different pricing for different protocols and, if a very specific and unique device is needed, there will be a very narrow market and there will be less opportunity to obtain a device that uses the existing protocol.
An open platform web server that can communicate seamlessly with different protocols and be accessed via an IP address is required to resolve this. In a nutshell, the web server lives at the top of the network tree and in open protocol systems, such as Lon, bacnet and modbus, the sub-networks all communicate seamlessly back to the web server and exchange data with the web server.
Once all devices are communicating either on the same open protocol network or via a web server, it is a matter of programing the systems’ interoperability. What this means is programing the exchange of relevant data between the systems. We want data that is useful – not junk – for effective integration.
For example, when the EMS notices that a power consumption set point has been exceeded and that the outside air temperature is within limits (as sent from the BMS), the compressors’ start is delayed (the EMS flags the BMS to activate the delay part of the code for the A/C unit). There are infinite strategies like this – the only limitation is our imagination to solve the challenge.
To be effective, an EMS and BMS need the ability to trend log. If a system doesn’t have this functionality it is highly obsolete and should be avoided.
Metering and sub-metering
Let’s assume that an EMS has been installed and a large amount of data is now available from different electrical energy meters. What now? What do we do with this data?
There are two options. The first is to add an additional software package that will display graphs programmed to provide the relevant information via an IP address. The programming of these graphs is critical to their usefulness. There is no point in producing graphs without a comparison or verification benchmark that enables you to see whether results are occurring and whether the strategies in place are delivering data that verifies the return on investment of these strategies. Ultimately, the results are reflected in the power bill and NABERS rating of a building. Ideally, the facilities manager (or supplier) should be tracking energy usage in line with the strategies in place.
The second option is to export the EMS data to Excel or a similar program. Energy meters can be separately exported to an Excel file and energy suppliers can email a building’s daily power usage to you in Excel form, showing not just the power consumption per feed, but the power factor as well. Extract outside air temperature, room temperature and other data trend logs from the BMS and export these to Excel. If you bring these files together, you can interpret the data to see where you can make improvements.
The time to do this may not be available; however, if a BMS and EMS are well set up with trend logs, it is just a matter of training an employee or using an external supplier to help out.
OTHER SYSTEM INTEGRATION ADVANTAGES
Systems integration on site can provide a proactive opportunity for building management. For example, if the BMS is interfaced into the vertical rise system and a fault has developed in one of the cars at seven am, the system will send an email to the facilities manager’s phone. The facilities manager can then send a pre-set email broadcast to all tenants to let them know that they are aware of the problem and that the service supplier has been notified to rectify the situation. This means that there won’t be any nasty calls to the building manager, the supplier will be on their way and the tenants will appreciate having a proactive building management company managing their building. The cost to implement something like this would be circa $5000 (subject to the site system).
There is also an additional opportunity to add value when it comes to sub-metering as NABERS looks favourably upon this when an assessment is complete.
I’ll end with a final note that may save you money. We talked about the market and the number of vendors earlier in the article. If an existing system is with a large vendor, there will be a feeling of either loyalty or captivity. There are a lot of system vendors – big and small – that can offer great services and competitive pricing for an existing system and new systems – both BMSs and EMSs. This is the whole point of open protocol systems – to open up the market and cease single vendor captivity. In Sydney alone there are around 35 control and EMS vendors. How many have you called?