Optimal design of pumping stations of inland intensive fishfarms

An algorithm for selection of least cost or optimum pump combinations in water supply systems and to evaluate the system's energy cost of inland intensive fishfarms is presented. The model is based on solving a non-linear programming problem. Optimum design refers to the selection of pump type, capacity, and number of units that results in minimum design and operating costs for a given water demand curve. The optimization process consists of three main steps: (1) determination of fishfarm daily water requirements; (2) determination of all sets of pumping stations that satisfy the maximum requirements of flow and energy head of the fishfarm water distribution network; and (3) selection of the least-cost set among the feasible sets of pumping stations. The model was established based on data from an actual eel fishfarm in southern Spain. Application of the model shows that the optimal solution with the pump operation scheme at a constant rate (maximum requirements of flow) saved 70% of the actual total annual cost of the pumping station. The optimal solution with a variable pumping rate (pumped flow adjustment to match demand) saved 92% of the actual total annual cost with all fixed speed pump groups. Savings about 95% were obtained when one variable speed pump group was included in the optimal solution.