Design Issues

High distribution uniformities and efficiencies can be achieved when hydraulic design produces the pressure required for the selected sprinkler discharge, with acceptable variation within the system, and when the layout design is based on optimal sprinkler spacings. The design of the system layout, including the selection of sprinklers and respective spacings is dealt with in several publications [11, 94, 96, 98, 99], as are the hydraulics of sprinkler systems [11, 96, 106-109]. Several engineering standards also support appropriate design (ASAE S261.7, S263.3, S376.1, S394, S395) [19].

Uniformity [DUor CU, Eq. (5.119) and (5.120)] resulting from adjacent sprinklers can be estimated by simulation of the overlap of four adjacent sprinklers in a rectangle, or three in the case of a triangle. The effect of wind can be considered by changing the original circular pattern into an ellipse with radii that vary with the wind speed [91].

The design also should aim at achieving high efficiencies. Considering that the application efficiency depends upon the uniformity, Keller and Bliesner [11] propose to compute the distribution efficiency DEPa (%) corresponding to a desired percentage pa of the irrigated area receiving the target irrigation depth (or area adequately irrigated):

DEPa = 100 + (606 - 24.9pa + 0.349(pa)2 - 0.00186(pa)3)( 1 - — ), (5.150)

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Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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