Small gas turbine technology

Small Gas Turbine Technology: Small gas turbine, in the power range up to 500 kW, requires a recuperated thermodynamic cycle to achieve an electrical efficiency of about 30%. This efficiency is the optimum, which is possible for a cycle pressure ratio of about 4–1. The cycle airflow is function of the power requirement. To increase the efficiency, in view to reduce the CO2 emission, it is mandatory to develop a more efficient thermodynamic cycle. Different thermodynamic cycles were examined and the final choice was made for an Intercooled, Recuperated cycle. The advantage of this cycle, for the same final electrical efficiency of about 35%, is the smaller cycle airflow, which is the most dimensional parameter for the important components as the heat exchanger recuperator and the combustion chamber. In parallel with the thermodynamic cycle it is necessary to develop the High Speed Alternator technology, integrated on the same shaft that the gas turbine rotating components, to achieve the constant efficiency at part loads, from 50% up to 100%, by the capacity to adjust the engine speed at the required load. To satisfy the stringent requirement in pollutant emissions of NOx and CO, the catalytic combustion system is the most efficient and this advance technology has to be proven. The major constraints for the small gas turbine technology development are the production cost and the maintenance cost of the unit. In the power range of 0–500 kW the gas turbine technology is in competition with small reciprocating engines, which are produced in large quantity for automotive industry, at a very low production cost.