Development of an Energy Saving Pilot Solar Powered Reverse Osmosis Underground Water Purification Plant Using Low Cost DC to AC Converter for Water Supply to Remote Off-Grid Rural Communities

摘要

The paper presents development of a pilot autonomous stand alone solar powered reverse osmosis water purification plant using three phase PWM (VSD) inverter topology with control strategy to overcome input dc voltage fluctuation and a low cost 800W DC-AC converter for cost effective portable water supply to off-grid rural communities. It uses external hydraulic pressure from high pressure feed pumps applied to concentrated solution forcing pure water through a permeable membrane. The inverter’s output is configured for multiple AC motors connected in parallel to drive two parallel pumps with independent low friction piping system to produce required flow resulting to less wear, noise, water hammer control among others. The novel technology employs both deep-discharged nickel cadmium batteries with wide DC input voltage range (24V- 180V) and pumped water as storage medium while the low energy requirement of series connected photovoltaic modules with sun trackers operates at maximum power point to produce reasonable amount of power. The AC submersible centrifugal pumps working on Affinity law principle saves significant amount of energy and are configured to match head and discharge requirement of the application. The result appears to show that the system is efficient in water supply, energy saving and pollution free.