PV-powered membrane system control for continuous autonomous water solution in remote areas
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Date
2025
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Publisher
University of Namibia
Abstract
This research addressed the challenge of Solar Irradiance (SI) fluctuations, which
adversely affect the performance of photovoltaic-membrane (PV-membrane) systems
used for water purification. These fluctuations lead to reduced permeate volume and
quality, as well as increased specific energy consumption. The primary aim of this
research is to incorporate mechanical energy storage and develop a hydraulic buffering
control method to enhance system performance under varying SI conditions. To achieve
this, a hydraulic energy storage system utilizing a bladder tank was implemented, designed
to buffer periods of SI fluctuations. A control algorithm was developed that allows the
hydraulic bladder accumulator to discharge during low solar irradiance periods for
buffering and charge during high solar irradiance periods by monitoring power ramp down rates. Results indicate that, in the worst-case scenario of a very cloudy day, the
system produced an additional 98.5 L of permeate while maintaining permeate quality
within the WHO palatable limit of 1.13 mS/cm. Furthermore, the average specific energy
consumption was reduced by 38%. The algorithm effectively prevented system pressure
from dropping to zero, thereby maintaining system stability despite fluctuations caused
by SI changes. Future investigations should focus on minimizing pump shutdowns during
hydraulic buffering due to increased pressure resistance. This research contributes to
sustainable water solutions in remote areas, offering a promising approach to enhance the
reliability and efficiency of PV-powered membrane systems
Description
A thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in Renewable Energy
Keywords
Solar Irradiance (SI) fluctuations, Photovoltaic-membrane, Water purification, Hydraulic energy storage system, Namibia, University Of Namibia