microturbine operation is represented by the brayton cycle. in this cycle, the compressor first raises the pressure of the ambient air to the required pressure ratio. the compressed combustion air is then routed through a non-mixing exhaust-to-air heat exchanger called a recuperator. the recuperator allows the microturbine to utilize a portion of the exhaust energy to preheat the incoming combustion air. by using preheated air in the combustion process, less fuel is necessary to obtain the exhaust temperature required for expansion across the turbine. this results in an increase in the overall fuel-to-electrical efficiency of the microturbine.