|Energy management requires both measurements and an understanding of the process. The measurements are very simple to obtain and can come from most standard accounts packages. The measurements need very little treatment to give vital information on the site and process operations. Energy use is not fixed and uncontrollable, it is variable and controllable and is directly related to the production volume of the site.
The Performance Characteristic Line (PCL)
Get energy and production volume data for at least 12 months. Use a spreadsheet to plot the energy use for the month (kWh) versus the production volume for the month (kg) as a sca tter chart and use the same spreadsheet to insert a linear best fit trend line to generate to PCL. The equation for the PCL gives the ‘base’ and the ‘process’ loads of the site and the correlation coefficient (R2) indicates how well the PCL fits the data.
The Base Load
The base load of a site is the intersection of the best fit line with the vertical axis. It is the ‘energy overhead’ and for plastics processing will range between 20 and 40% of the total load of the site. A low base load generally indicates good management control of energy at the site and a high base load generally indicates poor management control of energy at the site. Reducing the base load is easy to carry out, low cost and has rapid payback. Savings in the base load are very profitable because the base load is largely a dead weight that is unrelated to production output.
Download the Booklet