Selection process of photovoltaic standalone pumping systems

Abstract

Abstract The application of a standalone photovoltaic (PV) system for water pumping has increased nowadays in remote areas of developing countries due to proven economic feasibility compared to other traditional alternatives. Pump–motor set manufacturers always give the pump characteristic at the motor's nominal speed. The traditional selection process of pumps depends simply on selecting a pump with the highest peak efficiency that can satisfy the desired duty point with its peak efficiency occurring at that duty point. However, this simple selection process could lead to selecting a pump that is not the best selection from among a given set of candidate pumps for the targeted service. In this paper, this fact is revealed by comparing two pumps each having the same peak efficiency and each of them can operate at the desired duty point with one critical difference between the two pumps. One of the two pumps has its peak efficiency occurring at the right of the duty point and the other has its peak efficiency occurring at the left of the desired duty point. The methodology of this research is based on calculating the daily efficiency of each pump by calculating the hydraulic power produced with the electrical power of the solar system. The efficiency calculation has been calculated over two working days, one with low radiation (3 kW/m2/day) and the other with high radiation (7.3 kW/m2/day). The search for the all-day efficiency for low radiation levels revealed that the pump with left-shifted peak efficiency gives 42.5% while for high radiation level gives 40.3%. In two cases the pump with left-shifted peak efficiency constitutes the best choice.

Keywords

• Solar Energy
• PV system
• Pump System
• Centrifugal Pump
• Duty Point
• Induction Motor