Advanced Gas Turbine Engine Exhaust Waste Heat Recovery System

Navy ships use of gas turbine engines for both main propulsion and electrical power generation. With typical simple cycle thermal efficiencies of around 32-35%, a great deal of energy is lost as exhaust waste heat from the gas turbines. Clearly there is a need to develop systems that can recover as much as possible of this waste energy, and as stated in the program goal, achieve at least a 20% reduction in fuel consumption. Also important is the avoidance of steam systems and machinery, due to their high maintenance characteristics, hence non-aqueous solutions only are to be considered. To meet these program requirements, Candent Technologies proposes to investigate a waste heat recovery system utilizing an air (Brayton) bottoming cycle with the requisite heat exchangers and turbomachinery, and also to conduct trade studies to determine the most advantageous configuration, as well as to further define the system by carrying out a preliminary design effort. The baseline system chosen will be the 501K17/K34, since the characteristics of their exhaust are well suited for the effort, and the resulting matching energy recovery system should make for a reasonable size and cost in a follow on Phase II and Phase III programs.