The Externally Fired Gas Turbine ( EFGT-Cycle ) and Simulation of the Key Components

The externally fired gas turbine unites two advantages. On the one hand, the utilisation of the waste heat from the turbine in a recuperative process and, on the other, the possibility to burn “dirty” fuel. In particular, the EFGT opens a new option to utilise biomass for combined-heat-and-power and contributes to reduce greenhouse gas emissions. A micro gas turbine with 100 kW electric output is chosen as an example to study the effects of temperature difference and pressure loss in the gas-to-air heat exchanger on cycle efficiency and power. The simulation calculations are performed with the codes AspenPlus and GateCycle. In addition to cycle optimisation the effect of low-calorific biogas on the combustion air ratio and the possibility of solar energy as a heat source for the EFGT are studied.