The importance of open systems

Open systems protocols for building controls are probably not high on the list of interests for even the most dedicated building energy manager. However, the development and evolution of protocols such as LonWorks, BACnet, KNX, Modbus, M-Bus and others has had a significant impact on how building energy use can be monitored, measured and managed.

Moreover, this applies to new-build projects as well as refurbishment of existing commercial buildings.

The development of open systems, and the move away from manufacturer-written protocols, has created a much more open market for controls. Specifiers and end-users can now select the controls they want to use – even using a variety on one project if they can see a benefit. Clients need no longer feel that they are locked into a single supplier.

One of the major benefits of this is that buildings can be more easily future-proofed. Building controls are constantly developing, and open protocols mean that a building owner can take advantage of new controls technologies without having to completely remove an existing system and start again. From an energy efficiency point of view this is vital because building services equipment such as boilers, air handling units and lighting are all achieving ever-higher efficiency levels.

Open systems such as those listed above allow controls installers to incorporate that equipment more easily. There is an increasing amount of packaged building services plant that includes manufacturer-incorporated controls. Before open systems became so prevalent, a proprietary interface would have been necessary – and that would have been far more time consuming for the systems installer.

Open systems create a much more efficient platform for integrating services into a building management system. In the days when a chiller or boiler had its own proprietary controls, the controls engineer would have had to disable those, creating the need for ‘double engineering’ which wasted time and money.

As more energy managers are looking to find cost-effective ways to reduce energy waste in their buildings, the ability to upgrade equipment is increasingly important. But in today’s economic climate, a whole-system or whole-building approach is not financially viable. With open systems, it is possible to migrate gradually to new controls and other new services kit, taking a step-by-step approach.

It is also possible to add extra energy efficiency measures to a system’s existing sensor array. For example, a lighting system may use PIR sensors for occupancy detection. Open protocols allow this sensor to be linked to local controls for fan coils so that cooling as well as lighting is used only when required, with extra energy efficiency benefits. There are further benefits when the existing head-end for the building management system can be retained as new equipment and features are added, reducing the cost of new energy efficiency measures.

By taking a staged approach to energy efficiency by building on an existing open protocol, it is possible to demonstrate the financial benefits of energy efficiency measures – and perhaps use these savings for further investment in an efficiency programme.

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