Drip irrigation design based on different pressure units

The costs of micro-irrigation can be reduced effectively by using optimal design methods and by reasonably using pressure head supplied by pressurized pump. In this paper, a simple optimal design of the pressurized pipe is proposed based on minimizing capital costs and the present operational cost. In the design of the main pipes, a two-stage optimal design method is used. In the first design stage, the pipe cost is minimized and a set of optimal manifold pipe diameters and optimal friction losses are obtained by using a non-linear optimal model. In the second design stage, partial lists of available diameters are prepared based on the stage-1 optimal diameters, and the lengths for available diameters are calculated by using a linear optimal model and simplex method. In addition, because the pressure regulator is not set on the inlet of subunits, the subunit close to the pump gets higher pressure head than that far from the pump. Less irrigation working hours should be used in the subunit with higher pressure. Therefore, the energy cost of the drip irrigation system can be decreased compared to previous design strategies. As a result, a new design procedure is developed in this paper.