Enhancing micro gas turbine performance through fogging technique: Experimental analysis

This paper describes a test bench that has been designed to implement the fogging inlet air cooling technique to a 100. kWe Microturbine (MGT) and reports the power and efficiency increase of the machine. Indeed, one of the main issues of MGTs, which has also been observed and documented in large sized gas turbines, is their strong sensibility to inlet air temperature. One of the most interesting technology in terms of low plant complexity to limit the MGTs performance loss is the high pressure fogging. Although cooling down the inlet air temperature with this technique has already been analyzed for medium/large gas turbines systems, there are very limited reports available on MGTs and few experimental data are documented.Results show that the machine's electric power gain depends on ambient humidity and it ranges from 5% to 13% (corresponding to an inlet temperature drop between 4 and 10. °C) in the location where the plant is installed. Power enhancement corresponds to 1.03. kW for each Celsius degree of inlet air temperature reduction. As regards the electric conversion efficiency, the increase reaches about 0.41%/°C. Being the inlet air saturation the thermodynamic limit, the absolute power and efficiency gains are the higher, the hotter and drier the climate is.