Modeling and Performance improvement of a Beta type Stirling engine for Cogeneration of Heat and Electricity

In this paper a beta type Stirling engine for cogeneration of heat and electricity is proposed. The Stirling engines have advantages such as flexibility of fuels and heat sources, low noise level, and higher thermal efficiency than internal combustion engines. In these engines, in power production process, some heat is released to the environment, which can be recovered, and therefore the Stirling engine has a good potential to be used in combined heat and power systems. In this research, the non-ideal adiabatic analysis has been used for the Stirling engine and for enhance the accuracy of the model, the frictional and thermal losses have been considered. Non-ideal adiabatic analysis, was performed using a numerical code developed in MATLAB software. To validate of the model, the geometrical and operational specification of the GPU-3 Stirling engine was used and the results were compared with experimental results and other previous models. Then a beta type Stirling engine was proposed for the combined heat and power system in residential applications. Also, the effect of engine rotational speed, regenerator length and temperature of heat source on electrical and CHP efficiency were investigated and the appropriate amounts of operating parameters were selected. Finally, the electrical power and thermal power were obtained 11263 W and 21653 W, respectively with electrical efficiency of 27.78% and CHP efficiency of 81.19% efficiency for this cogeneration system.