Responding to the need to reduce energy use and carbon emissions

Published:  11 August, 2009

David Kitching
Continuous improvement in CO2 reduction and financial savings — David Kitching.

David Kitching argues that improved management techniques and automatic controls for buildings are essential to deliver 24/7 the needs of the occupants, accountants and chief executives.

Businesses are looking to display their green credentials by cutting back on energy usage to reduce their carbon footprint, and their financial and facilities managers are looking to reduce spend on utility bills. The continued increasing cost of fuel and the rise of more stringent legislation mean businesses can no longer rely on outdated methods to control their energy use plus the need to prove adherence to the corporate sustainability strategy.

In addition, UK Building Regulations, European legislation and standards and our elected politicians are imposing demands that not only require copious amounts of information to satisfy the rules but also year-on-year improvements to meet targets already set for 2010, 2020 and 2050.

The CRC (Carbon Reduction Commitment) comes fully into force next April, requiring evidence packs, early actions and growth metrics. A shortfall of performance could add £100 000 to costs (energy not saved) plus, in the first year, the required two year additional cost of £24 per CO2 tonne for the additional emissions carbon permits. That is a serious impact on cash flow and overheads compared to a competitor managing energy effectively.

Similar to the way an airliner or the simple motor car require the aid of computerised management systems to fly or transport occupants safely, a building can now be considered to be no different as it needs the same type of system to function efficiently.

To meet the demands of new legislation and play your part in the overall need to reduce carbon footprint, it is imperative that you set hard targets for all your energy-consuming and carbon-generation activities by undertaking an energy health check to pinpoint those areas where there is most to gain. Siemens can provide this essential knowledge, which extends well beyond building services.

The importance of data collection cannot be over-emphasised as it provides the basis for the complete management process by providing that vital knowledge of how the building is being used and where energy is consumed. Now that simple metering is a mandatory requirement of Part L2 of the Building Regulations it is time to look beyond just the accumulation of hourly, daily or weekly consumption data, as this can only highlight the past. To achieve correct management of energy use, continuous online monitoring of supply and consumption must be undertaken to enable rapid detection of waste and inefficiencies.

Modern meters can provide a variety of information that can indicate not only total consumption but many other parameters that help you to understand the quality of the energy and this information, coupled with the behaviour of the plant (running, stopped, loaded, filtered, recently maintained etc.), keeps you completely informed of any remedial action required.

Using standard open protocols such as Modbus, Mbus, Profibus or BACNet can ensure that the information needed for a proper analysis can be accessed by the building energy management system (BEMS). Details of harmonics can help to show if power supplies for laptop computers and mobile telephones supplies have been left on, and information from variable-speed drives can advise on the relative efficiency of the plant being controlled.

Man at computer
Bringing information from meters in real time to a BEMS enables the right control action to be taken when deviations in consumption occur.

To achieve the above it is essential that all metering is connected in real time to the BEMS so that the right control action can be taken when deviations in consumption occur. The Siemens Desigo BEMs, for example, provides the capability of recording data, setting variable limits and instructing controllers in the field to maintain precisely the right conditions for comfort and efficiency. A monitoring package such as ADP (Advanced Data processing) coupled with the Reaction processor enables all the building attributes to be monitored and controlled for maximum effectiveness. Reports can be generated to allow greater analysis of control as the need to improve is dictated by the legislation.

Optimum start and optimum stop can be interlaced with occupancy figures and departmental usage so that every opportunity is taken to achieve savings by, in most cases, eliminating waste.

To ensure that controls are effective, it is imperative that BEMSs are installed by specialists with a very clear understanding of mechanical and electrical plant and all the latest regulations for each discipline. European proposals that are in place and others on the horizon need to be implemented. You should also look for strict conformity with the highest rating of the new eu.bac recommendations for the best possible energy efficiency.

Data on consumption and how the building is used should be compared with the original health check to ensure that a continuous reduction in energy consumption is being obtained. Figures show that a systematic approach to this challenge will deliver up to four times greater efficiencies than stand-alone measures.

A systematic attack on the issues with well prepared data will ensure maximum return on investment, lowest lifetime costs, facilitate compliance with regulations and deliver what are now essential management tools.

The message is clear. The monitoring of energy consuming equipment for performance and metering consumption will provide much-needed information, but without closing the loop and allowing the BEMS to take action continual improvement in CO2 reduction and financial savings will not be achieved.

David Kitching is with Siemens Building Technologies.

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By presenting a wide range of measurements in graphical form, a BEMS enables problem areas to be readily identified.


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