Power Plant Driven by Residual Heat Rejected by the Bottoming Low Pressure Steam Turbines

Abstract

The work deals with thermal engine structures undergoing load based expansion-contraction processes powered by the residual heat rejected by low pressure turbines of the bottoming steam Rankine cycles. The isobaric expansion-contraction based thermal cycles at constant load referred to in this paper, is characterised by its high thermal efficiency at low temperatures, since such thermal cycle doesn’t obey the Carnot statement. Such bottoming energy convertor must be implemented in cascade with the low pressure turbine of the steam Rankine cycles at combined cycle power plants, including nuclear power plants. An analysis of the ideal isobaric expansion-contraction based thermal cycle is carried out and results are compared with the Carnot cycle operating under the same ratio of temperatures. Hydrogen and helium have been chosen as working fluids due to its high specific heat capacity and thermal efficiency. The satisfactory results obtained from a simple and compact installation envisage the way towards a new generation of thermal power plants.