Energy consumption measurement helps save energy in industry

Energy efficiency is a topic of unprecedented concern these days. We are all acutely aware of the problems of climate change and environmental pollution caused by the burning of fossil fuels, and the need to reduce our carbon footprint. Even without other pressures, rising costs would be enough to warrant attention; electricity consumption has increased by an average of 5% to 10% per year in recent years. However, many industrial processes were designed before there was a mandate to be as "green" as possible and to use as little energy as possible.

It stands to reason, therefore, that many manufacturing processes could see significant reductions in energy input without affecting output and production quality. Sometimes savings can be achieved simply through inspection; for example, there may be a motor or heater that runs continuously, when in fact it is only needed for part of the production cycle. Other potential savings are less obvious and can only be discovered through more detailed investigation of the process in question. The fundamental principle of regulating any system is to understand in detail how it operates, and this requires measurement; as the famous 19th century physicist Lord Kelvin said, "If you can't measure it, you can't improve it." Surprisingly, energy measurement for many energy-intensive processes can be relatively under-utilized. The latest building codes in many countries will introduce higher energy monitoring standards, but existing facilities are not equipped with such basic metering devices, and most of these facilities will continue to be used for many years. The energy consumption

of automobile fuel tank manufacturing

is on the top of the agenda of INERGY Automotive Systems, a car parts manufacturing and vehicle assembly company. In 2008, the company launched a project to optimize and reduce the company's energy consumption as part of its internal sustainable development strategy. INERGY is a world leader in the development and manufacture of automobile fuel tanks, especially advanced plastic fuel tanks. INERGY Automotive Systems was founded in 2000 as a joint venture between Plastic Omnium and Solvay, focusing on plastic fuel tank systems. Today, the company has developed into a leading Tier 1 supplier of plastic fuel tank systems to major global automakers. INERGY Automotive Systems is headquartered in Paris, France, and currently has 24 production sites in 18 countries around the world. In 2009, INERGY produced and supplied 9 million fuel tank systems to major global automakers, with sales of EUR 900 million.

The project, now known as INeco: INERGY Energy Optimization for Energy Efficiency, was created when the group’s total electricity consumption was about 228,000 kWh – a consumption pattern that is almost entirely electrical, and roughly equivalent to the amount consumed by a European town of 60,000 people. The INeco project and overall deployment were led by Stéphane Duval and Joseph Brossard. The project began with a series of energy audits of the main existing manufacturing processes at INERGY plants, starting with the Pfastatt site in France. The

first audit was carried out in 2009, with the aim of: collecting detailed information on energy consumption over a period of three weeks; analyzing the information collected and using the results as the basis for an action plan. Of course, each plant had an electricity meter at the input of the grid to provide the power company with bills, but the audit required a more secondary electricity metering solution to collect instantaneous current data for each machine and process. To carry out the energy audits of the existing plants, the project required the configuration of a temporary electricity metering solution; therefore, its installation and removal had to be simple and quick. Traditional cabled energy metering solutions were initially considered for

the monitor installation

, but such a metering system proved difficult and expensive to implement in such a short period of time. With few “plug and play” metering solutions on the market, the only realistic alternative was LEM’s Wi-LEM wireless energy meter. Wi-LEM energy meter nodes are open core current sensors; they can be clamped onto a conductor without any connections to allow for the placement of continuous loop sensors or series sensors. They give INERGY the freedom to install the measurement nodes in each distribution cabinet at the most accessible location, and most importantly, without requiring downtime. Despite the system’s ease of installation, the measurement nodes still provide energy metering accuracy that exceeds the IEC 62053-21 standard by 1% or more.

The “wireless” part of the Wi-LEM name refers to the fact that it transmits data via a wireless mesh network. This transmission method has two benefits; wireless operation means that no cables are required for any temporary installations; and “mesh” indicates that the wireless data collection network between the measurement nodes and the central data collection point is self-organizing. LEM uses a very reliable, industrial-grade protocol based on the IEEE 802.15.4 mesh network standard to ensure data transmission. Cable-free installation does not mean that the system can only be used for temporary installations. Many users may need to continue detailed energy consumption investigations by installing long-term monitors at key nodes to ensure that savings are maintained and that power consumption patterns are not repeated. Reliable wireless mesh networks meet the latest specifications for the installation of factory data collection systems, making them ideal for long-term monitoring. In

September 2009, the first Wi-LEM temporary network of 40 measurement nodes was deployed at the Pfastatt factory. The Wi-LEM uses a 3-phase delta configuration and has a measurement range of up to 2000A. The sensor nodes use LEM's Rogowski coil, a Perfect Loop technology without discontinuous coil clasps. The measurement frequency of this innovative sensor is set to 240 current values ​​per day for three weeks, which results in a huge amount of data - more than 200,000 instantaneous current values. As a result, the INERGY team had to design a method to extract the maximum information and value from this data set. The first precaution was to do a quick “sanity check” on the data. The integration of these current measurements should have been equivalent to the electricity usage on the utility bill. The agreement between the two values ​​was better than 97%, which again proved that the data was sensible, so the INERGY team continued with the analysis phase of the project.

Data Analysis

The current data collected was stored in a single large database, which also contained minute-by-minute information on all processes in the plant; which systems were being used, which products were being manufactured, and each moment corresponded to a current data point. INERGY’s tank manufacturing is based on a blow-molding process: high energy consumers include heating the molding material, compressed air supply, and post-molding cooling. Data analysis showed that the blow-molding machines accounted for 45% of the company’s total energy consumption: the exact figure was not known before the audit. Compressors provide high pressure (13 bar) for blow molding, and they consume a lot of energy – the analysis showed that compressed air leaks were wasting a lot of energy. The energy consumption of the cooling water process (chillers, pumps) was also compared with theoretical energy consumption, indicating potential savings. Measurements to Optimize Performance This finding led equipment vendors to explore how to reduce the energy consumption of such equipment. Not all findings were related to specific manufacturing processes; standard commercial building systems can also waste energy if not properly managed. Database data showed that some of INERGY's HVAC (heating, ventilation and air conditioning) and lighting systems were set to run continuously throughout the day, regardless of whether employees were present in the service area of ​​the equipment or whether the temperature needed to be adjusted.

Because the Wi-LEM unit is portable, it was quickly removed after the audit of the Pfastatt factory was completed and reinstalled in subsequent secondary audits at INERGY's facilities in Anderson, USA and Ramos, Mexico, which once again confirmed its advantages. The initial experience with the Wi-LEM wireless energy meter was repeatable, proving that the unit is very easy to install and configure. The INERGY team also found that the wireless network's RF signal was strong enough to ensure data transmission even in electrically noisy industrial environments. Wi-LEM uses the maximum RF output that an unlicensed transmitter can use in the mesh network, 100mW. The value of this feature was demonstrated during an audit of the Anderson plant in the United States, where the switchboards had double insulated metal doors; there were no connectivity issues at any point in the network.

The overall data suggests that savings of 15% can be achieved without significant infrastructure spending. The measurements required to achieve these savings are often simple and common sense: once the data is available, it can show what actions must be taken. (end)