How Power And Gas Demand Control Systems Can Help Mills Cut Utility Costs

There is one quick way to substantially reduce the operating cost of a great many pining operations. It is to cut the demand charge on the use of electricity and gas. Demand charge is the utility company's charge for the maximum rate of energy usage which is in addition to the charge for the total amount of energy used. Energy demand is reduced by prohibiting simultaneous operation of devices, especially those that consume large amounts of energy, or by deferring the use of such equipment as air conditioners from one demand period to a subsequent period. To achieve that end, a control system can continuously measure the demand and turn off selected loads in accordance with established rules. Because of the complexity of most industrial plants, a computer is the best means of storing, measuring, calculating, and controlling the many variables associated with the many devices involved. A computer system for that use has been developed by the Westinghouse Computer and Instrumentation Division in Orlando, Florida. For most applications, this demand control system can be installed and operated by industrial plant engineering personnel with no special knowledge of computer technology. It can be used with both electrical and gas service. For clarity, let us examine electrical demand first.