Take control of energy management

08May

posted by: Alan Hickman, Carlo Gavazzi UK

The once-separate markets of building control and energy management are merging to bring the smart building to life, cut consumption and lower fuel bills.

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Are building automation and energy management different disciplines? I would argue that the two technologies are rapidly overlapping and ultimately will become one. Indeed, the integration of these two technologies is becoming paramount.

Although the fundamental foundations are pretty much defined, the technology, and the ways you can gather data and control the building, is growing exponentially, driven in part by energy legislation, corporate social responsibility and the desire to cut fuel bills.

At Carlo Gavazzi, we have always had a foot in both camps. When Carlo Gavazzi entered the energy management market many years ago, the sector was driven by systems integrators and panel builders incorporating metering on the primary incomers to measure what was happening within the building. Data acquisition systems evolved so that you can gather all that metering data, analyse it and report on it. The energy manager was born.

The other side of the business is building automation. This is driven by controls systems houses, incorporating building management systems (BMS) to control and integrate the lighting, air conditioning and other building services.

Increasingly, we are seeing BMS companies offering energy solutions and the energy management providers diversifying to offer small-to-medium controls solutions on single and multi-site applications. The overlap is becoming quite considerable as awareness among end-user clients grows.

Two-wire bus drives forward

A simple, two-wire bus system, such as Carlo Gavazzi’s Dupline system, offers the best of both worlds, and offers many advantages over conventional solutions. In typical building automation systems, each data point needs to be wired back to the direct digital controller (DDC). This complicates the installation, particularly in applications with widely-distributed data points.

The Dupline two-wire bus technology significantly simplifies the field level wiring, eliminates expensive wiring home runs and saves money on 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.

Two-wire bus systems reduce commissioning time and offer the possibility to integrate HVAC and lighting controls, for example, at the field level – one network, two solutions. Systems are based on bus-powered sensors and small I/O modules. The cost savings of such a decentralised I/O solution can be considerable.

Flexible, modular and expandable

The beauty of a two-wire bus system for smart buildings 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, again saving on the cost of any future expansion and accommodating any last-minute changes.

Carlo Gavazzi’s Dupline two-wire bus system provides many other advantages too. Unlike RS485 based solutions, Dupline 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.

The Dupline system perfectly accommodates the convergence of building automation and energy management. The latest generation of Dupline employs a BACnet gateway to connect to energy meters - all data points from these and the Dupline network are automatically converted into BACnet objects, ready to be integrated into the building automation system.

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: i.e. 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.

Specifiers also need to be aware of the EU Measuring Instruments Directive (MID) for any meter to be used in conjunction with the re-sale of electricity. This legislation became effective on 30 October 2006, with a 10-year transition period, and replaces Ofgem’s Schedule 7 of the Electricity Act 1989. Any new meter to be used directly for billing must be MID-approved after October 2016.

Star City entertainment complex

An example where Carlo Gavazzi has brought all of this technology together would be Birmingham’s Star City mega leisure and entertainment complex. A network of MID-certified energy meters and a Dupline bus-based lighting control system helps tenants save energy as well as costs.

With around 36,400m² of leisure space and 2400 secure parking spaces, Star City is one of the largest leisure complexes in the UK, comprising one of Europe’s biggest cinemas, the largest indoor adventure golf complex in England, a 22-lane bowling alley, all-weather 5-a-side football centre, open-plan gym, Laser Station and family climbing centre. It attracts 3.5 million visitors per year.

It is a multi-tenant site on a grand scale, so it’s vital that each tenant is billed accurately for their energy usage. The current network of EM21 energy meters provides three-phase energy metering across the site.

According to the Building Research Establishment, controls are the easiest and most cost effective solution for saving energy in buildings. Clients and building occupiers, however, have failed to exploit advanced control solutions, says the BRE, because many of the innovative technologies they employ are perceived to be overly technical and complex to operate. This, when coupled with a lack of information on the subject, has resulted in a poor uptake of control technologies and a subsequent failure to significantly reduce the carbon footprint of buildings and to provide a better environment for occupants.

Simple two-wire bus solutions such as Carlo Gavazzi’s Dupline system offer a cost-effective means of improving the poor take-up identified by the BRE, tackling energy reduction and improving occupant comfort.