MILP OPTIMIZATION OF A CHP ENERGY SYSTEM

To support its technology, a factory may consume heat and power. We ca n produce them inside the factory or buy them from an outside plant. F or production of these energies, we use a CHP energy system consisting of a steam boiler and a backpressure turbine. Using a steady-state, b ottom-up approach, a network of energy modules and mixed integer linea r programming (MILP), we have developed a software package KOM9. Depen ding on the unit costs of different kinds of energies, we found the co st region diagram. This diagram gives an energy plant operator a recom mendation for use of an optimum energy consumption of particular compo sition. This yields the minimum energy expense and, at most, 65.6% in cost saving. Regardless of an inexpensive production of the power, we show that sometimes it may not be optimal to operate the turbine. This is the case when refuse steam for heating purposes is available. (C) 1998 Elsevier Science Ltd.