Building controls and energy management: the perfect marriage

Once separate, building control and energy management are merging to bring the smart building to life and cut energy use and fuel bills, argues Alan Hickman, managing director at Carlo Gavazzi UK.

Building automation and energy management were once different disciplines. At Carlo Gavazzi, we have always had a foot in both camps. When the company 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.

The integration of these two technologies is becoming paramount. I would argue that the technologies are rapidly overlapping and ultimately will become one. 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.

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

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 level field wiring, eliminates expensive wiring home runs and saves money on installation costs when compared with traditional device-to-DDC solutions. Also, the 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.

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 flexible and modular, again saving on the cost of any future expansion and accommodating any last-minute changes.

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.

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 ten-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.

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.

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.

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