Monitoramento da irrigação por gotejamento com bombeamento fotovoltaico autônomo e direto

Abstract

Autonomous direct photovoltaic pumping is a sustainable technological solution that directly uses solar energy to power water pumps, without the need for batteries or electronic controllers. This system operates intermittently, following the variation in solar irradiance throughout the day, which makes its design and management a challenge. Therefore, the objective of this research was to monitor the uniformity of water application in a drip irrigation system powered by autonomous direct photovoltaic pumping. Three irrigation systems with hoses of different wall thicknesses and emitters from different manufacturers were analyzed. The experiment was conducted at the UNIOESTE Irrigation and Fertigation Laboratory, using a 10-meter irrigation bench. The photovoltaic system consisted of a 150 Wp module connected directly to a submersible pump, without the use of batteries. Twenty-five trials were carried out per treatment, with flow rate measurements taken every 45 minutes between 9 a.m. and 5 p.m. under different irradiance conditions. The variables calculated included flow rate, pressure, irradiance, and hydraulic power, and the data were analyzed using Shewhart control charts and the Coefficient of Uniformity of Distribution (CUD). The results showed that the Aries (Netafim) and Irritec 1.1 L/h emitters showed excellent uniformity, with mean CUD values above 95%, even under average irradiance of 360 W·m⁻², while the Irritec 2.1 L/h model obtained lower uniformity (87%). It was found that hoses with greater wall thickness provided greater stability in relation to the system’s fluctuating pressure, improving application uniformity. Despite the greater hydraulic power observed in higher flow emitters, the choice of emitter should also take into account uniformity parameters and cost effectiveness, especially in autonomous systems without a controller.