Flexible and fast – the new normal for building controls

Alan Hickman, Building Research Establishment, BRE, two-wire bus system, I/O modules, Carlo Gavazzi UK
Alan Hickman

Businesses constantly adapt the working environment to optimise performance. Building controls have to be equally flexible, easy to reconfigure and able to deliver control quickly and effectively. Alan Hickman discusses these challenges and how the latest controls technology can ease the strain of change as the new normal for buildings.

No successful business remains the same for long. Stand still and you get overtaken. Today, change management, organisational change and business process reengineering strategies are the new norm. Successful organisations are in constant flux: changing their focus, expanding or contracting their activities and rethinking their products and services. Many businesses more than ten years old look nothing like they did even five years ago. Who can predict what they will look like five years into the future?

Nowhere is this change more evident than in buildings. Externally, buildings are static structures, yet inside they are constantly evolving. In many organisations, office layouts are subject to frequent changes. Churn rates for offices are higher than ever before as businesses continually attempt to optimise staff performance through the work environment.

According to the Building Research Establishment (BRE), 60% of the buildings that will be standing in 2050 are already built. But what will be the requirements within these buildings to accommodate the changing and varied expectations of the occupants while meeting energy and carbon reduction targets?

When businesses decide to extend or change the layout of their building, whether that’s an office or a factory environment where new production lines may be introduced, this will have a considerable impact on the building services. The pressure is on for buildings to be as comfortable and energy efficient as possible, so tweaking of the building services is almost always underway to adapt to change.

The building controls strategy needs to be considered right at the start of any project in order to facilitate the likelihood of future changes to the building services. Building controls have to be flexible, easy to reconfigure and able to deliver control quickly and effectively.

The disadvantage with many conventional building control systems is that each data point needs to be wired back to the direct digital control (DDC) controller. This can make the initial installation more complex than necessary, particularly in those applications with widely-distributed data points. This approach also makes it difficult to accommodate future changes easily.

Take the bus

An alternative is a simple two-wire bus system for control of building services. This has major advantages where the workplace is likely to change in the future. It is flexible, modular and expandable. Two-wire bus technology significantly simplifies the field level wiring, eliminates expensive wiring home runs and saves money on wiring and installation costs when compared with traditional device-to-DDC solutions. Furthermore, the significant installation cost reduction is achieved without increasing material cost due to the reduced need for DDC inputs and outputs (I/Os) and standard sensors.

The beauty of a two-wire bus system is that it can be expanded by simply extending the bus cable and adding extra I/O modules. This means it is truly flexible and modular, saving on the costs of any future expansion and easily accommodating any last minute and future changes to office layouts.

A two-wire bus system (for example, the Carlo Gavazzi Dupline) offers many other advantages too. The two-wire bus system can be wired using free topology for the cable, including ring, star and so on. The cable does not need to be screened or twisted and it can be run next to power cables without fear of interference. Many of the field devices are powered by the bus itself which simplifies the installation by removing the need for additional power supplies.

Alan Hickman, Building Research Establishment, BRE, two-wire bus system, I/O modules, Carlo Gavazzi UK
Today’s office space must be flexible, and the building controls must allow for change of occupation and use over time

Energy boost

When moving offices or relocating departments, it is essential to integrate an energy management strategy into the change process to determine whether the transition has been effective. End users need to be able to monitor energy consumption in different areas and departments and this can be achieved by incorporating energy meters into the installation.

The two-wire approach accommodates the integration of building control and energy management. For example, the can include a Modbus to BACnet gateway to connect to energy meters. This means that all data points from the meters and the network can be automatically converted into BACnet objects, ready to be integrated into the building management system (BMS) or energy monitoring solution.

Take the example of the relocation of a company department to another part of the building. If the heating or lighting has been left on in an area of the building that is not currently used, the Dupline system will trigger an alarm on the energy management system which will allow further investigation by the building facilities team.

The first step in any metering strategy is to consider all energy that is imported or exported: main incoming supplies and renewables. The second step is to identify all sub-main circuits requiring meters: ie for end users, tenants and various activity areas. The third step is to provide metering that enables consumption loads to be identified in all key categories, such as: heating, hot water; lighting; small power; ventilation, pumps etc.

Re-commissioning and optimisation of a BMS system to reflect a building’s current and actual usage can reduce a building’s CO2 emissions by up to 20%. Metering data will provide visibility of excessive consumption and identify opportunities for savings through simple BMS strategy adjustments that doesn’t involve large capital expenditure.

Simple two-wire bus solutions offer a cost-effective means of improving the historically poor take-up of controls identified by the BRE. Integration of building control and energy management ensures end users have the information they need to make informed judgements about where power is being consumed. Only then can organisations take control and save energy. After all, if you can’t monitor it, you can’t manage it.

Alan Hickman is managing director of Carlo Gavazzi UK

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