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Development of an advanced low-cost hybrid electric power generator

Client: ERAfrica/Department of Science & Technology (South Africa)

Period: July 2014 – June 2017

Project leader: Peter Breuhaus (Norway)

Local project team, with other members from Belgium, Egypt, Norway, and Turkey.:

ERC: Gisela Prasad, Amos Madhlopa

Department of Electrical Engineering (UCT): Azeem Khan, Paul Barendse, Moin Hanif.

The project will use the Brayton power cycle gas turbine to convert the thermal energy produced from various thermal and mainly sustainable energy sources to mechanical energy. The resulting mechanical energy will drive the specially designed electric power generator. This project can be considered as a base for a family of different / larger size advanced high efficiency gas turbine (AHET) generators that can be made and become commercially available for the distributed generation market. A dual vane compressor which will boost the performance of the turbine if operated at high temperature will be designed. The expected specific fuel consumption of AHET will be lower than the specific fuel consumption for the combined cycle by allowing the addition of different sources of renewable energy. In this system, solar thermal energy will be utilized to heat the air delivered by the compressor in a specially designed heat exchanger before entering the combustion chamber. The combustion chamber will be provided with a dual fuel burner, to burn both liquid and gas fuels. Several different sources of thermal energy would be utilized to operate AHET including biogas (BG), natural gas (NG), bio-diesel (BD) in addition to solar thermal energy. Due to the high efficiency of the AHET, the emission is significantly reduced even if fuelled with NG. However, substantial reduction will be achieved through the use of BG or BD in conjunction with solar energy. To maximize the system efficiency, the exhaust gas leaving the heat exchanger (in the case of large size systems) can be utilized to preheat the inlet air or for industrial thermal applications such water desalination. Further reduction action of fuel consumption and improvement of thermal efficiency would also be achieved by utilizing a small portion of the electric energy generated to produce hydrogen by splitting water into hydrogen and oxygen by the electrolysis process. Part of the produced hydrogen will be mixed with fuel in the combustion chamber to boost the combustion process while the remaining hydrogen gas can be stored for later use.

Collaboration: International Research Institute Stavanger (Norway), Vrije Universiteit Brussel (Belgium), Fatih University (Turkey), Ain Shames University (Egypt) and University of Cape Town (South Africa).

Objectives: 1) To develop a mathematical tool for optimization of an advanced low-cost hybrid electric power generator, 2) To construct and test an Advanced High Efficiency gas Turbine (HSG-AHET) prototype in the field, 3) To establish a desalination plant operated on heat recovered from the electric power plant, and 4) To provide clean electric power to operate advanced agriculture projects for high-yield food production including hydroponic farming and intensive fish farming.

Methodology: 1) Generation of a layout concept, taking into account the physical and the engineering constraints. 2) Development of a mathematical model for system optimization in terms of steady state operation as well as in terms of modeling transients especially with respect to the inclusion of various sources of thermal energy and fuel, 3) Designing and manufacturing of the various system components, and 5) integration of the components and testing of the prototype.

Outputs: 3 research reports, and 1 prototype