TECHNOLOGY | ENERGY MANAGEMENT
Tangram Technology compares the Performance Characteristic Line (PCL) for two injection moulding sites. Although they are processing slightly different volumes of material it is easy to see that the poor site (upper line) has a very high process load, a high base load and a barely acceptable correlation coefficient. The good site (bottom line) has a much lower process load, a lower base load and a very good correlation coefficient. The poor site will have energy costs nearly three times that of the good site for the same production volume.
management agenda,” says Kent. “If energy use is not visible and measured then there will be no improvement. Every site needs an Energy Policy — a statement of commitment on energy use. This should include improvement targets for the short, medium and long terms. The policy should be widely distributed to encourage awareness of the costs and benefits of energy management.” He continues: “Energy management should be
the clear responsibility of the production depart- ment because they control most of the energy use. An Energy Manager can only act as the scorekeep- er and the process should be driven by production. Funds and time should be allocated to carry out energy management projects. Monitoring and targeting (M&T) are fundamental for energy management. A lot of data is probably already being collected but energy management is not about data, it is about providing information to target improvements. Targeting is the key action and what gets measured gets done.” Kent highlights a number of key actions re-
quired. These include: creating and distributing a formal site Energy Policy; assigning clear responsi- bilities for energy management; gathering initial data and converting this into information to manage site energy use; using the performance information to target improvements; and publish- ing performance information widely. “The ideal outcome of a good energy manage- ment programme would be a 30% reduction in
46 INJECTION WORLD | June 2020
energy use and costs,” Kent adds. “This is made up of 10% through management – the simple recogni- tion that there is a problem and taking normal man- agement actions. Simple maintenance work costing less than £2,000 (US$2,500) can also account for 10%. Longer term work requiring investment is the final 10%. Energy is a variable and a controllable cost and over 30% of the energy spend is ‘discretionary’. This means that you choose to spend it because you either do not have the skills or the real desire to do something about it. The actions taken vary depending on where you are in the development process. Beginner sites can start with services management and then move on to more complex process-oriented projects. Experi- enced sites should be looking at process-oriented projects from the start.” Services use, such as compressed air and
chillers, for example, will be approximately 30% of the energy use at an injection moulding site, says Kent. These are some of the most productive places to look for improvements and there are many things that can be done to reduce services use. These include: reducing compressed air leakage, compressed air generation pressure and use of compressed air for drying or product movement. The chiller operating temperature can be increased or chiller use can be eliminated altogether with air blast cooling. He adds that after the services are examined, machines and process needs can be examined for improvements such as: n For existing hydraulic machines consider the option of retro-fitting VSD controls or servo motors, in fact, any of the technologies that allow the speed of the main motor to be reduced when the need for oil decreases.
n Barrel insulation is a real ‘no-brainer’ in almost every case. It is easy to fit and maintain and has a payback of less than one year.
n Look at the downstream equipment, for example conveyors, regrinders, blowers and assembly equipment. Use automation or good processes to shut these off when the main machine is not operating.
n Shut down chilled and cooling water feeds when the machine is not operating. They use energy to pump the water around and will suffer from parasitic heat gain.
n Shut down the compressed air feed to the machine at the drop to avoid losses from any leaks on the machine or system.
n If using hydraulic machines, then investigate using a new generation high viscosity index hydraulic fluid.
www.injectionworld.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
