XAG: a tool in the design improvement of power plants

Abstract

Abstract

A computer program XAG has been developed for aiding the design of arbitrary thermal power plants. It is the third in a series of software developed for evaluating the thermo-dynamic and economic performances of power plants operating on the Brayton and/or Rankine cycle. The mechanics of operation of XAG is described in this article and the use of the software is illustrated in the design improvement of a turbo fuel cell. The tenets on which the software was developed are that power plants must be designed for minimum cost of plant product(s) and that this minimum cost must occur at a performance level that is practical and which reflects the state of the art. It is necessary, therefore, that the analysis of plant performance be carried out on an exergy basis and that the optimization be conducted on a thermoeconomic basis. The results of the analysis of the turbo fuel cell show that the cost attributable to the fuel cell was primarily due to capital cost, whereas that attributable to the gas turboset was due primarily to exergy destruction in the components of the gas turbine. It was concluded that research efforts should be directed at reducing the capital cost of fuel cells to make the technology competitive.