EXTENDED ABSTRACT

Introduction

Growing agricultural water demand and increasing limitations of conventional energy resources have intensified the need for sustainable water supply solutions. In many rural and remote areas, access to electrical grids remains limited or economically impractical, while diesel-powered pumping systems are still widely used despite high operating costs, maintenance requirements, and environmental impacts. Photovoltaic (PV) solar water pumping systems provide an effective alternative by directly converting solar energy into mechanical energy for water extraction and irrigation, offering low operating costs, reduced emissions, and reliable long-term operation. Iran, especially provinces such as Hamedan, possesses considerable solar energy potential while agriculture depends heavily on groundwater pumping. Unlike grid-connected pumps operating under stable electrical supply, PV-driven systems must function under continuously varying input power caused by fluctuations in solar irradiance and ambient temperature. Motor–pump selection therefore becomes a critical design parameter affecting efficiency, reliability, and water delivery. Although many studies have investigated photovoltaic water pumping systems, most focus on a single motor technology or use simplified assumptions, limiting direct comparison. This study presents a comparative evaluation of a photovoltaic solar water pumping system using four motor–pump technologies. A real deep-well pumping system located in Razan County, Hamedan Province, Iran, is selected as the case study. The objective is to determine the configuration that achieves higher energy efficiency, stable operation, and improved water delivery while assessing economic feasibility under different water pricing scenarios.

Materials and Methods

A combined analytical and simulation-based approach is adopted. Hydraulic power demand is calculated using flow rate, total dynamic head, and water properties while accounting for pipeline losses. Pump and motor power ratings are determined using efficiency-based relationships to ensure proper matching between hydraulic demand and electrical supply. The photovoltaic array is sized to meet system energy requirements while considering system losses and seasonal solar radiation variations. To ensure fair comparison, all scenarios employ the same PV array capacity, and only the motor–pump technology is varied. Motor efficiency characteristics and operational behavior under variable input power are incorporated into the model. Simulations are performed using PVsyst software, which models PV module performance, system losses, and load operation. Four independent simulations corresponding to BLDC, induction, brushed DC, and PMDC motor configurations are conducted under identical climatic and hydraulic conditions.

Results and Discussion

Results show that motor–pump technology significantly influences photovoltaic water pumping performance. Among the evaluated configurations, the BLDC motor–pump system achieves the highest technical performance. This configuration exhibits the greatest Performance Ratio, indicating more efficient utilization of available solar energy. High efficiency and a wide operating speed range allow stable operation under fluctuating solar conditions, resulting in consistent water delivery throughout the year. The BLDC system also produces the highest annual pumped water volume and closely satisfies irrigation demand, while unused photovoltaic energy is minimized, demonstrating improved matching between energy generation and hydraulic load.

Conclusion

The study confirms that motor–pump selection is a key factor affecting both technical and economic performance of photovoltaic solar water pumping systems. Among the evaluated technologies, BLDC motor–pump configurations provide superior energy efficiency, maximum water delivery, and improved operational stability under variable solar conditions. Although economic feasibility depends strongly on regional water pricing, the technical advantages demonstrated support the adoption of BLDC-based photovoltaic pumping systems as a sustainable solution for agricultural water supply in solar-rich off-grid regions.



Introduction

Growing agricultural water demand and increasing limitations of conventional energy resources have intensified the need for sustainable water supply solutions. In many rural and remote areas, access to electrical grids remains limited or economically impractical, while diesel-powered pumping systems are still widely used despite high operating costs, maintenance requirements, and environmental impacts. Photovoltaic (PV) solar water pumping systems provide an effective alternative by directly converting solar energy into mechanical energy for water extraction and irrigation, offering low operating costs, reduced emissions, and reliable long-term operation. Iran, especially provinces such as Hamedan, possesses considerable solar energy potential while agriculture depends heavily on groundwater pumping. Unlike grid-connected pumps operating under stable electrical supply, PV-driven systems must function under continuously varying input power caused by fluctuations in solar irradiance and ambient temperature. Motor–pump selection therefore becomes a critical design parameter affecting efficiency, reliability, and water delivery. Although many studies have investigated photovoltaic water pumping systems, most focus on a single motor technology or use simplified assumptions, limiting direct comparison. This study presents a comparative evaluation of a photovoltaic solar water pumping system using four motor–pump technologies. A real deep-well pumping system located in Razan County, Hamedan Province, Iran, is selected as the case study. The objective is to determine the configuration that achieves higher energy efficiency, stable operation, and improved water delivery while assessing economic feasibility under different water pricing scenarios.

Materials and Methods

A combined analytical and simulation-based approach is adopted. Hydraulic power demand is calculated using flow rate, total dynamic head, and water properties while accounting for pipeline losses. Pump and motor power ratings are determined using efficiency-based relationships to ensure proper matching between hydraulic demand and electrical supply. The photovoltaic array is sized to meet system energy requirements while considering system losses and seasonal solar radiation variations. To ensure fair comparison, all scenarios employ the same PV array capacity, and only the motor–pump technology is varied. Motor efficiency characteristics and operational behavior under variable input power are incorporated into the model. Simulations are performed using PVsyst software, which models PV module performance, system losses, and load operation. Four independent simulations corresponding to BLDC, induction, brushed DC, and PMDC motor configurations are conducted under identical climatic and hydraulic conditions.

Results and Discussion

Results show that motor–pump technology significantly influences photovoltaic water pumping performance. Among the evaluated configurations, the BLDC motor–pump system achieves the highest technical performance. This configuration exhibits the greatest Performance Ratio, indicating more efficient utilization of available solar energy. High efficiency and a wide operating speed range allow stable operation under fluctuating solar conditions, resulting in consistent water delivery throughout the year. The BLDC system also produces the highest annual pumped water volume and closely satisfies irrigation demand, while unused photovoltaic energy is minimized, demonstrating improved matching between energy generation and hydraulic load.

Conclusion

The study confirms that motor–pump selection is a key factor affecting both technical and economic performance of photovoltaic solar water pumping systems. Among the evaluated technologies, BLDC motor–pump configurations provide superior energy efficiency, maximum water delivery, and improved operational stability under variable solar conditions. Although economic feasibility depends strongly on regional water pricing, the technical advantages demonstrated support the adoption of BLDC-based photovoltaic pumping systems as a sustainable solution for agricultural water supply in solar-rich off-grid regions.