PROCESSING | ENERGY MANAGEMENT
Management needs to get serious about energy consumption
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Robin Kent, Managing Director of Tangram Technology in the UK, consults widely on energy management in plastics processing. He made a few pointed remarks to Injection World on the subject: One of the biggest changes in the world of energy efficiency is the impact of the Industry 4.0 data revolution. Data are now so easy to obtain from low-cost sensors that the biggest problem is how to handle the mass of data being generated. The issue here is not getting the data (which are just a set of numbers) but how to translate the available data into information (which can be used for assessment, comparison and management action). The techniques of data handling and treatment (either simple software or more complex cloud-based algorithms) are relatively well-known and easy but attracting, and retaining, management attention to the resulting information is still a major problem. Most plastics processing companies still do not regularly report on their energy performance at board Level and, even when they do, they tend to use the fatally flawed ‘kWh/kg’ value as a monthly performance metric. (KWh/kg is unduly influenced by the produc- tion volume: increasing the production volume in a month will automatically decrease the kWh/kg, due to the effect of the base load being amortised over a larger process load.) These companies inevitably spend more time discussing how to
increase sales or manage debtors than they do on how to de- crease costs. Perhaps this is because they regard energy costs as fixed and uncontrollable which is wrong on both counts. One of the most exciting new developments in energy efficien-
cy is the ABB Ability Smart Sensor. This can be fixed to the frame of any standard LV induction motor (they use about 60% of the energy in plastics processing) to continuously monitor the rotor health, the temperature, the bearing condition and vibration. This data can be transmitted via Bluetooth to a secure cloud-based server where it is analysed to calculate the instantaneous power, operating hours and a host of other operating parameters, which can in turn be sent to a smart phone or dedicated application to advise on service intervals and maintenance as well as energy consumption. There are equally exciting developments in areas such as
retro-fitted servo motors, improved hydraulic oils and improved drying controls. These all have the capacity to change and reduce how we use energy in processing plastics. But none them will make any real impact unless we start to convert the data they generate into meaningful management information and then convince management to take the necessary action. These technology advances are vital but real change is still needed at management level so that management sees energy as a key operational financial indicator and not simply a number that is relegated to the annual ‘Sustainability Report’.
38 INJECTION WORLD | May 2019
Left: GWK Protemp temperature controller fitted with Proflow ultrasonic water distributor
eral pumps available on the market which are installed in most temperature control units, these can achieve enormous potential savings of up to 86% under the same operat- ing and series production conditions, GWK claims. This is because a centrifugal pump has a significantly higher flow rate
at the operating point than a comparable impeller-type peripheral
pump, with low energy input at the same time. “In terms of performance, therefore, this means that up to four conventional temperature control units can be replaced by just a single GWK Protemp,” the company says. A Protemp Connect communication interface
allows Proflow water distributors with electronic flow and temperature measurement units to be connect- ed to the Protemp temperature control unit, so that measured values for up to 12 temperature control circuits can be monitored in the temperature control unit controller and shown on the device display. “The preferred solution for measuring the flow
rate in the Proflow distribution system is by means of maintenance-free and contactless ultrasonic flow measurement,” says GWK. “The control pump adjusts the flow rate of the unit in response to changes in production conditions, to individually meet the specific requirements of each process.” In combination with its Integrat Direct controlled
water distribution system, the company says, this means that not only can the flow rates of individual circuits be adjusted to thermal requirements, at a higher level the entire flow rate for the tool can also be adjusted to the minimum overall flow required for the process and hence the minimum possible energy input. The energy consumption of the pump in each case is shown on the display of the temperature control unit. “A perfectly coordinated system of pump
hydraulics, motor and frequency inverters, with power reserves, allows a continuous boost function with permanent utilisation of the maximum pump speed, without any notable increase in pump wear,” GWK claims. Using the OPC UA interface, the speed can even be predefined from the injection-moulding machine controller or any other
www.injectionworld.com
PHOTO: GWK
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