Large energy savings in process plants are possible with appropriate wireless monitoring. Increased energy efficiency is of prime importance and can result in huge cost savings.
As energy costs continue to skyrocket, optimizing energy consumption becomes a strategic imperative for plants, factories and commercial facilities alike, while simultaneously minimizing carbon footprints. The first step in improving energy efficiency is to understand, where, when and how much energy is used. An energy monitoring system based on wireless sensor networks can wirelessly gather this information and enable energy-saving decisions by comparing real-time consumption data against set targets.
Energy-intensive plant processes such as heat, steam and compressed air are low-hanging fruits for energy management initiatives. Industrial energy control on the strength of extending sensor reach to these processes can yield very high return on investment. Even a small improvement in plant energy efficiency here will be visible on the balance sheet, resulting in lower operating costs and improved competitiveness. Besides monitoring of energy consumption and identification of inefficiencies, energy management may also entail shifting of demand to off-peak hours, in order to benefit from a lower tariff.
In many countries around the world, governments are currently tightening up regulations pertaining to the reporting requirements for energy usage. Major utilities are overhauling their metering infrastructure to cope with this challenge, but even individual devices and machinery in the industry will eventually be required to provide comprehensive energy usage data. With wireless sensor networks, such metering applications can be realized very easily. Wireless network nodes can be equipped with a pulse interface for direct interconnection with pulse output meters. Each received pulse is time stamped, assuring accuracy of energy amounts and use patterns even in the event of delayed data transmissions. Data transmitted by individual network nodes is then aggregated by a gateway, which can interface with most energy management and SCADA systems using fieldbus protocol. In principle nearly every existing sensor or meter can be integrated to this kind of network nodes via standard analog and digital input channels.
Renewable energy sources such as wind and solar are becoming increasingly popular for distributed generation. In a wind farm, sensing and monitoring of operational parameters plays a key role due to variability in wind speed and direction, the need to detect abnormal behavior before energy production and safety are compromised and the enormous costs attributed to maintenance.Wireless sensor networks are ideally suited for condition monitoring of critical turbine components such as bearings, gearbox and generator, especially due to the difficult-to-reach nature of the wind turbine and the typical spacing between turbine rows and multiple turbines within a row. For large-scale solar plants, wireless monitoring of the orientation and performance of collector arrays is equally economical and essential.
Similar to energy metering, real-time and accurate knowledge of water usage can aid in substantial reduction of sewage treatment bills. Wireless sensor networks can be used to wirelessly interconnect flow meters for measuring the amount of sewage water let out by plants and factories, the inflow of water into treatment plants and the flow and quality within all stages of the purification process. Individual devices operating in different locations can be accessed and managed via GPRS from a centralized control center. This enables elimination of undesirable manual tasks and site travels for data gathering purposes, as well as optimization of processes which result in reduced environmental burden and early recognition of water quality problems.
