Design and Implementation of Energy-Water Nexus Management in a Solar-Powered NFT Hydroponic System

The Nutrient Film Technique (NFT) is one of the most commonly used types of hydroponic systems due to its high yield of the crop and suitability for industrial scale. However, NFT systems require electrical power to ensure the continuous flow of the nutrient solution through the system. This study presents an energy-efficient method which is suitable for solar-powered NFT hydroponic for the growth of collard greens. The system comprised of two tanks as nutrient reservoirs. A 40 L tank was placed above the 70 L tank at a height of 90 cm. From the upper reservoir, the nutrient solution flowed through a solenoid valve into the system by gravity at a maximum flow rate of 4 L/min which continuously decreased during the emptying phase. Float switches were used to monitor the level of the nutrient in the upper tank for automatic refilling. The pumping system composed of a solenoid valve and a pump was considered as the largest energy-consuming part. Reducing the operation time of the pump and valve enabled the overall system to save 66% of the total energy consumed by the conventional NFT.