Direct solar photovoltaic powered reverse osmosis plant

The availability of fresh groundwater in regions with low rainfall in the western parts of South Africa is limited. Especially in regions where sheep farming is prevalent and farms have to be big and thus remote to be profitable. The big and remote nature of these farms means that boreholes on the farms often have no connection to the national grid. Luckily, these regions also have the highest solar harvest potential. This creates a unique opportunity to use solar power to desalinate brackish groundwater in these regions. Storing energy produced by solar panels is a challenge in these regions as the mean annual temperatures are high. The proposed solution is to use a direct solar powered Reverse Osmosis system to desalinate the brackish groundwater found in these areas. Due to the nature of reverse osmosis, each system is unique and has to be designed for the specific application. There is no one size fits all solution. With the help of simulations, the system can be designed and optimized for the specific application before the system is built. In this thesis the theory and design of a direct solar powered RO system is discussed. The reason for choosing a direct solar powered RO system over a battery backed up system is also discussed. The simulation of the system is also discussed in detail along with all the assumptions and calculations that make up the simulation. The simulation was then used to explore the idea of using active control to increase the performance of the system. The active control uses a combination of motor speed control and valve position control to optimize the performance of the system given the available solar power at any given time. The simulation was then verified with experimental results from a small scale direct solar powered RO system. After the verification of the simulation, the simulation was used to compare the performance of a system with active control to a system without active control, as well as systems with only motor speed control or only valve position control. Using the simulation, it was found that using active control to adjust the speed of the motor and the position of the valves, greatly increases the amount of clean water produced by the system, while minimizing the amount of waste water produced. It was also shown that using only motor speed control or valve position control does not achieve the maximum result and thus both are needed to achieve the best result.

Grantor dc:publisher

Stellenbosch : Stellenbosch University

Year dc:date.issued

2026

Author dc:creator

• Claassen, Rudolf Johannes Jacobus

Advisor dc:contributor.advisor

• Strauss, J. M.

Language dc:language.iso

en

Repository record dc:identifier.uri

https://scholar.sun.ac.za/handle/10019.1/135691

OAI identifier oai:identifier

oai:scholar.sun.ac.za:10019.1/135691