For all materials conversion processes (not just plastics processing), it is possible to set up a model system for either a plant or a machine, where the total electrical load (in kw) consists of a fixed base load
(the services) plus a process load that is directly proportional to the production rate in lb or kg per hour.
This will vary with the size of the base load-i.e., a high base load as a proportion of the total load will generally result in a lower apparent process load.
2) shows a base load of 30% of the average total energy use and a process load of 0.4487 kwh/kg (0.204 kwh/lb) of plastic processed.
3) shows a base load of 17% of the average total energy use and a process load of 2.4905 kwh/kg of plastic processed.
4) shows a base load of 30% of the average total energy use and a process load of 1.1479 kwh/kg (0.522 kwh/lb) of plastic processed.
([PV.sub.1] is production volume for Process 1; [PV.sub.2] is production volume for Process 2; and Base [Load.sub.1+2] is the overall plant base load.)
The base load information implies that even if no production is taking place in this plant, it will still consume around 152,440 kwh/month.
The base load is effectively an energy "overhead" and is generally due to machinery or services being left on with no productive output.
These are often more difficult to achieve than reductions in the base load.
The PCL will have a high base load, a lower than normal process load and high scatter in the results (a low [R.sup.2] value).
The base load will be high because processes and services are left on whether the site is producing any product or not.