Analysis of power, mass, and size parameters of solar vapor-turbine two-circuit systems with organic working bodies

The power efficiency, mass and sizing parameters of two-circuit solar vapor-turbine systems based on an organic working fluid are analyzed. Calculations are performed for systems using a diphenyl mixture as the working fluid and incorporating a jet condenser which condenses the flowing vapor and acts as a heat pump with two-stage refrigeration and heat removal by radiation. Expressions for the power efficiency and the specific radiator area (with respect to useful electric power delivered) are derived in terms of radiator emittance and efficiency, mechanical pump power required, pump efficiency, adiabatic temperature drop and the thermal balance equation, and it is shown that these parameters depend on the jet condenser parameters. Estimates of the effects of vapor flow pressure and the temperature of the liquid upon entry to the jet condenser on system efficiency and specific area are then presented, and an alternative to the device considered which overcomes its limitations of high specific radiator area by the division of vapor flow into two parts following first-stage regeneration is presented. Calculations show that the jet condenser is capable of providing the required circulation in both systems.