The next challenge in the globalized world will be to provide populations in developing countries the easy access to fresh water and electricity. However, most of the rural population in sub-Saharan Africa and Southeast Asia live in scattered agglomerates that make the building of traditional infra-structure (electricity grids and water systems) not feasible from an economic standpoint. The key to overcome this issue will be the installation of micro-plants that will be able to generate energy and water to fulfill these populations needs.
The proposed system will produce electricity using a Stirling engine with a rated electrical output of 3.5 kW and up to 500 liters of fresh water daily. This system will eliminate the daily commute of rural populations on their access to fresh water, that can amount to up to 6h per day. Moreover, it will provide a path towards a more sustainable future, since the production of electricity from the Stirling engine will eliminate the need for burning fossil fuels.
The Stirling Engine collector will receive solar radiation that will be used in two ways:
1. Heat the termal fluid used in the water purification process;
2. Heat the Stirling Engine working gas.
Stirling engines have been around for a long time, but their application potential has been reduced since they need maintenance, and compared with PV solar panels their cost is higher. However, if combined with other systems that will use the unused energy from the Stirling Engine, the application potential increases dramatically, since we are producing two products: fresh water per World Health Organization Standards and electricity. Also, on the proposed design simplicity was considered paramount as there is no need for lubrication due to the used of sealed bearings, and most of the components are derived from conventional internal combustion engines, making replacement parts procurement easier. Most of the parts are made using conventional technologies such as milling and casting.
Solar Radiation will focus on the 2.4m diameter parabolic collector which will concentrate the radiation into the Stirling Engine collector reaching a temperature of up to 600ºC. This collector will also have installed a tube bundle that will heat the thermal fluid and provide heat to the thermal distiller.
The Stirling engine works on the principle of temperature differential between the hot and cold sources that will expand and shrink the working gas, which in this case will be Helium at a pressure of 8 bar. The hot source will be the Stirling collector while the cold source will be ambient air that will cool the working gas using the finned design of the piston encasing body.
The solar distiller tube bundle will use the heat from the collector to heat the dirty water in the vapourizer, that will evaporate and will condense on the condenser. The condenser will be colder since the dirty water will pass through the condenser before entering the vapourizer. After condensing, the purified water will fall into the clean water trays and piped to the fresh water tanks.