Panels increasingly need to address the energy monitoring needs of building managers to save costs and improve quality. As buildings account for close to half the UK’s energy consumption, it is understandable why energy monitoring has become a major concern. However, reducing the demand for energy in non-domestic buildings can only be done effectively if building managers know exactly where and when that energy is being used.
There is also an ever-growing raft of standards and regulations. A key consideration is the EU Measuring Instruments Directive, which the UK enacted into law in 2006. Its goal is to create a single market in measuring instruments; and approval to the directive is mandatory for meters used in billing applications.
Instruments must meet the essential requirements of the directive plus one of 10 instrument-specific annexes. For electricity meters, this is MI-003 (active electrical energy meters). In addition, the requirement for monitoring energy use is implicit in part L2 of the UK Building Regulations, which implements additional EU directives aimed at lowering overall energy consumption and reducing carbon emissions. Whilst not imposing specific requirements on individual buildings, these regulations address overall goals of five or 10 per cent savings a year throughout Europe.
Compliance as the starting point
Even for basic applications, installers are looking for meters that carry a dependable certification, guaranteed accuracy and high quality construction. If they are easy to fit and part of a range with a common platform, all the better. An example is the EM21, which were the first meters on the market to feature a detachable display, so can be mounted on a panel of just 72x72mm, or on a DIN-rail in only four modules. The compact panel size allows more meters to be installed on a single panel, simplifying installation and providing economies of scale.
Features like self-power supply, automatic phase detection, retrofit capability and application oriented programming all help to further accelerate the installation process and reduce costs.
The ability to send energy readings to localised building management systems is a basic requirement of an integrated system, whether for new builds or retrofit applications. Panel mounted smart meters provide vital data for automatic monitoring and targeting strategies, enabling property owners and managers to reduce the whole-life cost of buildings and additionally increase the capital value.
Notwithstanding these benefits, building regulations recommend energy monitoring as good practice. There is the further incentive that non-domestic buildings implementing an energy-saving strategy can readily achieve cost reductions of five per cent or more, with all the attendant savings in their environmental footprint.
Most integrated energy monitoring systems are based on compact meters sending kWh readings via pulse outputs to localised control building management systems. Extending this to sub-metering has become simply good practice, facilitated by the ever-expanding range of measurement parameters offered by today’s compact energy meters. Rather than a basic pulse output, data are transmitted via Modbus communications. This enables a comprehensive set of data to be monitored and analysed - for example, A, V, var and power factor as well as kWh. Compact, easy to install, and with retrofit as well as new-build options for installation, modern energy meters provide intelligence on energy and utility usage for sub-buildings, individual floors - even for specific rooms, plant and equipment.
Today’s building management systems also integrate more sophisticated, higher-end devices for analysing the incoming power supply at input to buildings and at further critical points in the system. Modern smart power, quality analysers can deliver precise measurements of harmonics and distorted sine waves – with valuable management features such as parametric analysis, time and date stamping and retransmission.
Information is power
Moving from simple pulse outputs to bus-based data transmission provides greater versatility and coverage, allowing energy meters and power analysers to integrate into intelligent building management systems. Here, custom or proprietary standalone software turns metered data into usable information that helps to make buildings more efficient and cost-effective.
Typical elements of energy management software provide an interactive synoptic interface allowing users to browse the monitored electrical distribution system and to see alarm conditions at a glance. A series of links gives access to real time data from each instrument. The measured variables can be displayed as trends and exported for reporting and further analysis. From these data, costs can be estimated and allocated amongst customers or departments, ideally with a structure that enables complex multi-contract tariffs to be managed.
Closer integration with building management systems is becoming possible as energy monitoring software moves into the cloud. This is a growing trend, increasing numbers of building management providers offer cloud-based services and software-as-a-service applications. Vendors meet the needs of cloud-based energy monitoring by introducing new gateways that sit on top of their measurement and control products.
Carlo Gavazzi’s new energy platform, for example, aggregates data from energy meters, local and remote intelligent I/O modules, such as temperature inputs and control outputs, via RS-485 serial links. It then exposes these data channels to local networks and the Internet by providing three different types of web service. A file transfer protocol (FTP) server enables data to be pushed to a management system or cloud-based service provider on a scheduled basis. HTTP client services allow data to be polled on demand. A built-in web server provides always-on access to real time data, trending and alarms.
Internet gateways like these also provide facilities for automatically sending critical alarms by email and SMS, direct to the supervisory or management teams. From individual apartments, through whole-building networks, to Internet and cloud services, the control panel has grown into a hub for energy data networks that extend right across the world.
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