Identification of Design Criteria for District Cooling Distribution Network with Ice Thermal Energy Storage System

Two (2) distribution network models of district cooling system with ice thermal energy storage system are presented in which the theoretical system pressure drop, system flow rate and flow rate requirements in each energy transfer station were determined. The hydraulic calculation and system simulation of distribution networks with and without secondary lines are evaluated based on system temperature difference set-point of 11 °C. Variable primary flow pumping system arrangement was used to improve energy usage and to eliminate the need for a distribution pump in the network. The system of nonlinear equations was solved using multivariable Newton-Raphson method. The linearized equations revealed that coefficient matrices formed between the two networks were different from each other which suggested that different decomposition algorithms must be used to properly determine the solution vectors. Optimization technique such as exhaustive search method was adopted to identify the piping network design criteria that could yield minimum overall cost.