The intelligent approach to maximising energy efficiency
Monitoring the performance of all building-services systems, including electrical plant, is the key to identifying and delivering energy savings.
The potential to reduce the energy consumption of existing buildings is boosted by adding intelligence to them. RICHARD HIPKISSS explores the need and the possibilities.In July 2004 Lord Rooker, Minister of State in the Office of the Deputy Prime Minister said in a written Ministerial Statement: ‘Energy used in buildings is responsible for roughly half the UK’s carbon dioxide emissions. Driving up energy efficiency of our buildings is critical to our success in achieving the carbon dioxide emission reduction targets.’ Shifting focus
Moreover, the focus is increasingly shifting to how much energy a building consumes in the operational phase, when inefficient management can needlessly waste energy. Intelligent energy metering provides a vital insight into the building’s consumption and can identify areas where savings can be made. In addition, evidence shows that operating costs are typically three times the capital required in acquiring the building and that maintenance costs can be twice the capital build costs. Investing in systems that can help reduce energy consumption can also reduce operational costs. Part L of the Building Regulations is being revised to ensure compliance with the legal obligations set out in the Energy Performance of Buildings Directive (EPBD). This directive, which comes into force in April 2006, is based on target carbon-dioxide emissions for heating, hot water and lighting. It requires that all building owners carefully meter and monitor their energy consumption and emissions, as the owner of a building will have to make this information available to prospective tenants and buyers. Based on this data, each building will be given an energy efficiency certificate with a rating from A to G. In buildings that regularly receive large numbers of visitors, this certificate must be prominently displayed in an area visible to the public. Approved Document Part L2 consolidates the energy conservation principles of earlier revisions. Perhaps the biggest change is that the regulation is now split into two parts; A covers new build and B covers existing buildings, not previously covered by the legislation. This means that those involved in new build or the renovation of a building with a total useful floor area of more than 1000 m2 must take cost-effective measures to enhance energy performance and measure the energy consumption of their buildings. The introduction of Part L2, the EPBD and the energy-certification scheme, are expected to radically improve the energy performance of UK buildings. Building owners will be required to provide prospective tenants or buyers with a report detailing cost-effective energy-efficiency measures. A complementary report will be influential in making a sale, and could increase the value of the property. Equally, it is unlikely that any organisation with a corporate social responsibility policy will be happy to occupy a building that is poorly rated. Struggling
Yet, many involved in the construction industry are worried by the new regulations since the industry as a whole is still struggling to enact the energy efficiency requirements introduced in the previous revision of Part L2, just two years ago. Indeed, Approved Document Part L2 will require a more holistic approach and the input of the whole design team from the beginning, since Part L2 requires that the energy efficiency of buildings be measured and demonstrated by reference to the whole building, not by the system of U-values used at present. Traditionally, maintenance roles have always been reactive, but with intelligent building-control systems in place, maintenance becomes intuitive and can be planned and scheduled. The advantage is that maintenance can be planned and budgeted, rather than considered only when the need arises. Such practice often results in maintenance works being delayed or even ignored. In addition, it is now possible for a single system to monitor gas, electricity, water, air and steam. Maintenance is significantly improved with immediate access to diagnostics and remote-device interrogation. For example, with the ability to capture information, it is possible to determine if and when a power-quality problem exists, thereby averting problems. This is particularly important in hospitals where disruptions compromise safety. Apart from simplifying the roles of maintenance staff, intelligent energy management is inexpensive. A recent study by the Energy Savings Trust revealed that installing technology to meter and monitor energy consumption has an average payback period of less than six months. A small increase in capital expenditure can reduce operational expenditure significantly. Empirical studies of metering solutions show an average 5% reduction in utility bills in a diverse range of buildings. Savings in the region of 2 to 5% can be achieved by better equipment utilisation and as much as 10% can be reached by improving the reliability of systems. Many people worry that the installation of such technology during retrofit is expensive and will cause too much disruption to the building’s occupants. In reality, the equipment and systems can be fitted cost effectively and without causing problems, in new and retrofit installations. In both situations, an existing Ethernet network can be used, and usually there is sufficient in-house IT knowledge to maintain it. Wireless and Ethernet technologies enable ‘plug-and-play’ and convergence to allow centralised control. Indeed, all of Schneider Electric’s own buildings have had this technology successfully installed during retrofit. Benchmark
In retrofit installations, there is the additional benefit that it is easy to benchmark energy savings. When a building has been operational for a period of time without this technology, the effects and advantages of intelligent energy management are immediately obvious. Richard Hipkiss is with Schneider Electric Ltd, Stafford Park 5, Telford TF3 3BL.