The Heat-Storing Micro Gas Turbine—Process Analysis and Experimental Investigation of Effects on Combustion

Abstract

Renewable energy sources such as wind turbines and photovoltaics are the key to an environmentally friendly energy supply. However, their volatile power output is challenging in regard to supply security. Therefore, flexible energy systems with storage capabilities are crucial for the expansion of renewable energy sources since they allow storing off-demand produced power and reconverting and supplying it on-demand. For this purpose, a novel power plant concept is presented where high-temperature energy storage (HTES) is integrated between the recuperator and the combustor of a conventional micro gas turbine (MGT). It is used to store renewable energy in times of oversupply, which is later used to reduce fuel demand during MGT operation. Hereby, pollutant emissions are reduced significantly, while the power grid is stabilized. This paper presents a numerical process simulation study, aiming to examine the influence of different storage temperatures and load profiles of HTES on the MGT performance (e.g., fuel consumption, efficiency). Furthermore, relevant operating points and their process parameters such as pressures, temperatures, and mass-flow rates are derived. As operation conditions for the combustor are strongly influenced by the HTES, the paper contains a detailed theoretical analysis of the impact on combustor operability and includes an experimental investigation of the first combustor design adapted for the compound and tested under higher inlet temperatures conditions.