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The design of a Stirling engine system for the Science and
Technology Train
T. Matsepe 1,2 , CJS Fourie 2 , L. Beneke 1
1. Department of metallurgical Engineering, Faculty of Engineering at Tshwane University of
Technology, South Africa, tebohomatsepe@yahoo.com, benekelw@tut.ac.za
2. Department of Environmental, Water and Earth Sciences, Faculty of Science at Tshwane University
of Technology, South Africa, fouriecjs@tut.ac.za
ABSTRACT
The Science and Technology (S&T) Train will need a constant electrical power supply. Although it is possible to
use a diesel generator system to maintain a constant electricity supply, it will result in an unnecessary use of diesel
and pollution. Alternative ways of electricity generation was investigated and it was decided that the best
alternative solution will be a Stirling motor that uses solar energy. The diesel generator system will only be used as
a backup system.
A design model of an Alpha V-type Stirling Engine has to be done and built, to supply approximately an amount of
100kw of electrical power, for household purposes on the Science and Technology Train. It is a double acting,
twelve cylinder engine with the hot cylinders and pistons at ninety degrees out of phase with cold and hot sides (six
cylinders each side). According to the Stirling thermodynamic cycle studies, an efficiency of more that 30% can be
achieved (in our design 33%), therefore an amount of 300kw plus is predicted to be captured from a source of heat.
The source of heat for this system is a solar parabolic dish collector, with the receiver that has been designed
purposely for better capacity and large amount of heat capturing. The collector is a super corrosive resistant
stainless steel tank filled with salt, with a heat exchanger and a synthetic oil fluid inside. The concentrated radiation
will then be transmitted to the oil in the receiver and some be kept as a thermal energy storage, from which it can
be drawn for use at night and, or cloudy days. The thermal energy storage will be achieved by pumping the heated
fluid to an insulated storage tank.
The receiver will be absorbing the incoming solar radiation, converting it into heat, and transferring this heat to a
fluid (synthetic oil) flowing through to the reservoir and finally to the engine. Cold Water will be used to cool the
cold side of the cylinders, thus absorbing some of the heat energy from the working fluid. The energy shall be
disposed to heat water in the geysers, by running it through a heat exchanger.
KEYWORDS: S&T Train, Stirling Engine, parabolic dish, salt heat exchanger,
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