Optimal design of secondary piping network in district cooling systems

Analyses the optimal design method, develops the optimal design model of the secondary piping network, which covers the discontinuous change in pipe diameter, and presents the solving method.  Based on optimization of an actual case, analyses the economic difference of conventional and optimal design method.  It is concluded that the life cycle cost of secondary piping network can be reduced by optimal design via weighing the initial investment of the secondary piping network and the power consumption of secondary chilled water pumps. Comparing with the calculating results of conventional design method with economical flow velocity of 0.8, 1.8, 2.5m/s, optimal design method can save life cycle cost by 14.3%, 16.2%, 39.9% respectively.