Outil d'aide à la décision pour le dimensionnement de systèmes de pompage solaire PV

Abstract

Water pumping systems are needed in a wide range of applications, going from irrigation to human use. The energy source chosen for this kind of systems depends on site geographic location and sources availability, thus where power grid connexion is not possible, alternative energy sources must be considered. Fossil fuels are commonly used for remote pumping systems, despite their high costs, required transformation and transportation, GHG emissions and costly and intensive required maintenance. The use of solar energy for water pumping involves several advantages as GHG emissions reduction, reduced maintenance costs and high availability. One of the mains advantages is the energy storage made by a water reservoir, thus avoiding the use of batteries. Nevertheless, several factors must be considered while correctly designing and choosing the pumping system components. In other words a solar PV pumping system is affected by location, pumping distances, intake water source, consumption profile and others. A poor match between components and specific characteristics of the application is common and can lead to low efficiencies and high investments. The proposed methodology offers an integral solution, considering important aspects for optimal dimensioning, which is able to guarantee the best possible configuration regarding performance as well as economic analysis. This methodology is implanted in an open-source computer tool that allows users to provide basic data as site location and meteorological data, water source type, consumption profile, and ground albedo. A components database is also uploaded with available pumps, PV modules and controllers. Two operation modes are considered regarding panel tilt, the first one considers tilt equal to the latitude and the second one look for the optimal tilt angle to maximise match between load and solar energy. The tool calculates the number of PV modules in series to match the nominal voltage of the pump and calculates the parallel PV modules so the probability of lack of water is held below a certain set point. This evaluation is done using several reservoir sizes, thus several solutions are stored. The optimisation process consists in choosing the best possible solution from the dimensioning process. As the probability of lack of water is considered in the first part of the process, it is the variable part of the initial investment that is used as a selection criterion. The result is a single PV pumping system (pump, controller, model, tilt angle and number of PV modules and reservoir size) that allows ensuring the optimal operation with minimum investment. Furthermore, a service tariff is proposed so the financial resources related to maintenance, exploitation and components replacement are gathered as the users take profit from the system. Tool tests show that the high amount of variables and the variability of solar energy make it necessary to design the PV pumping systems finding a compromise between performance and financial viability. The design of PV pumping systems for several applications has shown the importance of the reservoir size, since it acts as an energy storage system, allowing water consumption during the night and during cloudy days.

Date	9 Jun 2017
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Daniel Rousse (Supervisor)