LOT-BOILING FLUID SUPERCRITICAL CYCLES FOR POWER GENERATION

Abstract

The possibilities of application of low-boiling fluids in supercritical cycles of power plants (conventional and nuclear) which generate cheap electrical energy are described in this paper. Working fluid should have appropriate critical temperature in order to obtain high cycle efficiency. When the critical temperature of working fluid in the supercritical two-phase cycles is too high, there is no possibility for utilization of heat regeneration in a simple recuperator. High critical temperature in one-phase cycles makes heat regeneration ineffective. When the critical temperature is too low, great compression work is required due to the low fluid density and the efficiency of power plant decreases. Furthermore, the working fluid should have no corrosive effects and should be thermal stable at high temperature, nontoxic, easily available in nature and relatively cheap.Reduction of internal irreversibility of thermodynamical cycles ( i.e., increasing their efficiency) at supercritical conditions can be obtained by additional compression of a part or of entire flow of working fluid. It causes a decrease of useful power of turboset, thus limiting the possibility of realization of very large power-generating units.In addition, the results of calculation of the efficiency of supercritical cycles employing CO2 as working medium, are given.