THERMODYNAMIC ANALYSIS OF COMBINED ORGANIC RANKINE CYCLE USED FOR POWER GENERATION

Abstract

In this study the Combined Organic Cycle focuses the performance of two fluids R123 and R245fa. Though earlier studies hold innumerable options, this work provides a much clearer statement on IHE in subcritical ORC system setting a new model taking pressure drop by loops and pinch point into thought. The common operating fluids R123 and R245fa have been chosen for subcritical cases. A steady temperature of 200ºC is used for warmth supply while maintaining a constant mass flow rate of it is 1 kg/sec. The Engineering Equation solver (EES) software package is utilized for analysis. A different approach to calculation of most heat exchange in Internal Heat Exchanger (IHE) is use when modelling a supercritical cycle, due to large dynamic heat component close to the critical point. Also, an alternative approach is required to compute the outlet temperature of the warmth source and identify the point of the pinch in supercritical cases. The results prove that IHE is useful in a subcritical case, but will improve system performance only partially for the low pressure stage in a supercritical scenario. In subcritical cycle it’s discovered that power obtained is 27.33 kilowatt and cycle efficiency is 12.03% at an evaporator pressure of 1326 kPa and therefore the second law efficiency is 40.41% at an evaporator pressure of 1326 kPa using fluid R123. The cycle efficiency is coming out to be 11.27%, the second law efficiency is coming out to be 38.67% and net-work is 28.38 kW using fluid R245fa. Analysis is done on combined Organic Rankine cycle in which the exhaust coming out of heat exchanger of Brayton cycle is supplied to the Organic Rankine cycle. The analysis is done on both fluids R123 and R245fa. In combined cycle the combined efficiency, Rankine efficiency, Brayton efficiency is 12.43%, 11.79%, 10.72% respectively at heater pressure 2600 kPa for fluid R245fa and 12.43%, 14.04%, 10.99% respectively for fluid R123. Also, in this study various cases of Brayton cycle is analyzed such as simple Brayton cycle, with intercooling, with reheating and with both intercooler and re-heater. The study is done on fluids R123 and R245fa.