Design, Fabrication and Preliminary Performance Evaluation of a Portable Geared Solar Irrigation Pump for Smallholder Farmers

Abstract

Agricultural productivity in many regions is increasingly challenged by erratic rainfall patterns, climate variability and limited access to affordable energy sources for irrigation. Although solar-powered irrigation systems have emerged as sustainable alternatives to diesel and grid powered pumps, many existing small-scale systems operate under fixed pumping conditions with limited adaptability to varying irrigation requirements. This study presents the design, fabrication and preliminary performance evaluation of a portable Geared Solar Irrigation Pump (G-SIP) developed to provide flexible water delivery for small-scale irrigation applications. The developed system integrates a 150 W photovoltaic module, 40 Ah battery storage unit, a 48 V DC motor and a three-gear transmission mechanism to enable its operation under different pumping conditions. Preliminary test was conducted on the prototype to determine the effects of gear configuration on motor speed, static head and discharge rate. It was revealed that the highest static heads reached were 15.4, 12.0 and 9.5 m with discharge rates of 32, 28 and 21 L min⁻¹, respectively for Gear 1, Gear 2 and Gear 3. It was further observed that the battery required approximately 4.75 hours of sunlight exposure to fully charge the battery. This enabled the pump to operate for up to 10 hours using stored energy. The developed G-SIP combines portability, use of renewable energy, local fabrication capability and adjustable pumping performance in one irrigation unit. These preliminary findings demonstrate the potential of integrating an adjustable geared transmission system with solar energy technology to enhance the adaptability of small-scale irrigation pumps while reducing dependence on conventional energy sources.