Agro Fossil Free - Studio delle prestazioni di un impianto fotovoltaico autonomo a pompaggio diretto utilizzato per l'irrigazione a goccia

Descrizione generale

Photovoltaic (PV) energy attracts more people to pump water as a friendly environment technology and provide autonomy in many remote areas. Morocco characterized by its important solar potential, promote use of this alternative energy in agriculture. Photovoltaic water pumping systems (PVWPS) coupled directly to drip irrigation network represents an affordable technique that can be promoted without use of any capacitive device for electric or hydraulic energy storage. This paper aims to study performances of a standalone photovoltaic pumping system confronted to actual behaviour of incident irradiance. The system is based on a photovoltaic generator, a maximum power point tracking (MPPT) and direct curent (DC) converter, and a DC diaphragm pump connected to calibrated (Flow versus Pressure) orifices to simulate small drip irrigation network, mounted in parallel scheme to vary the pump operating point according to timely varied irradiance. The result showed that daily trend of solar irradiance influence considerably operating behaviour of the pump, consequently the performance of the standalone PV system is affected as there is inadequation between charges of the PV generator and the DC pump. The hydraulic efficiency trends showed a dispersion and varying performances according to irradiance change and to hydraulic system unstability. A method of governing hydraulic performance is proposed to improve the system efficiency and pressure stability as requirements for water distribution uniformity in drip irrigation network supplied by a standalone PV pumping system.