A Preliminary Study of an Inter-Cooled and Recuperative Microgasturbine Below 300 kW

During the last few years, a number of small microturbines (<100kW) have been tested in commercial markets. These microturbines have demonstrated low emissions, increased fuel flexibility, and reasonable durability. However, if these microturbines are to compete economically with larger gas turbines and reciprocating engines, manufacturing costs will need to be significantly reduced and thermal efficiencies will need to be increased. A preliminary study has been completed that evaluated larger and more efficient microturbines (∼300 kW) that operate at higher pressure ratios based on an intercooled and recuperated cycle. The thermal efficiency of the proposed concept increases to 34–37% and is competitive with larger gas turbines and similarly rated diesel engines. Two-stage turbocharger compressors and intercoolers that were developed by the automotive industry for high volume manufacturing will further improve the specific fuel consumption and specific power of this proposed microturbine concept. An additional benefit of the higher pressure, intercooled cycle is that the temperature of the exhaust gases exiting the turbine and entering the recuperator is significantly lower facilitating the use of lower cost materials in the recuperator.