PUMPING COST MINIMIZATION IN AN EXISTING DISTRICT HEATING NETWORK

District heating is expected to significantly contribute to the reduction of primary energy needs for heating in urban areas. This result is obtained through use of such as CHP systems, residual heat from industries or waste-to-energy plants, as well as the integration of renewable energies. The pumping system plays a crucial role and may significantly affect its performances. In this paper a large district heating system is considered. Various operating conditions corresponding with partial load operation are analyzed through a thermo-fluid dynamic model of the network. For each condition, the optimal set point of the various pumps is obtained. The set of optimal operating conditions is finally used to obtain a control strategy for the network. Results show that with respect to conventional control strategy significant reductions in primary energy consumption can be achieved.