Modelling and optimization of stirling engine for waste heat recovery from cement plant based on adiabatic model and genetics algorithms

Abstract

The Stirling engine presents an excellent opportunity for electricity production based on renewable energies by dint of its high efficiency, silent operation and ecological suitability. Despite the studies carried out on Stirling engine which are powered by renewable energies (solar energy, biomass), there are few works that deal with the recovery of heat loss from industrial sector and its utilization as heat supply for Stirling engines. In the current study, we demonstrate the potential of using an Alpha Stirling engine in order to recover the heat from clinker cooling during cement production. In the present work, adiabatic model and evolutionary algorithms are used to upgrade the performances of Alpha Stirling engine using a numerical modelling code developed in MATLAB software. The results of this work show that increasing engine speed increases the power to 23.52 KW at 3000 rpm. It was also found decreasing the cooler temperature to 280 K improve the performances of output engine. The augmentation of gas mass has a significant increase on output power due to the engine pressure augmentation. A multi-objective optimization was realized using Genetic algorithms and the Pareto optimal frontier was established for dual objectives. The final optimal results indicate the improvement of output power and efficiency to 11.92 KW and 67.91% obtainable at 91.11° phase angle, 2092.2 rpm speed, 0.035 m piston stroke, 288.26 K cooler temperature and 1.1184 g fluid mass.