Agrico’s new GPS module, which can be used with the company’s other Internet-based control systems on the web-based Rain interface, enables improved control over pumps according to the specific need of the pivots.
This can result in impressive energy savings. The module can be installed on any electrical pivot to monitor pressure at the end of the pivot point and operates in conjunction with Agrico’s pump control and a variable frequency drive to control pump and water pressure automatically and accurately.
The example shown in Graph 1 of a pivot with a large height difference between the highest and lowest points illustrates how the Agrico system accurately controls the pressure according to the requirement of the pivot.
The spray package demands a minimum pressure of 100kPa at the end of the machine for correct, uniform irrigation. Traditionally, an irrigation system is designed with a constant inlet pressure that continuously meets the maximum pressure requirement, which is at the highest point (about 450kPa in this case).
Now, thanks to Agrico’s new GPS system, the pressure at the centre can be varied between 240kPa and 450kPa due to the topography, precisely meeting the varied pressure requirements of the pivot and thus saving energy.
Since the pressure is controlled not to fall below the threshold values and the spray package is equipped with pressure regulators, the volume of water applied is constant, despite the slope. Power (kW) is the product of pressure (kPa) and flow (ℓ/s).
The power required for the pumps during irrigation is therefore directly proportional to the pressure applied.
The total energy for one revolution of the pivot is equivalent to the area under the pressure curve. Graph 2 shows the energy required for one revolution with Agrico’s automatic pressure control, as opposed to the energy that would be required if no control were applied.
In this case study, the energy-saving with Agrico’s new GPS pressure control was more than 28%.