Stirling Engine Robust Foil Regenerator Efficiency

Combined Heat and Power (CHP) systems are one of the solutions to save energy by utilizing waste heat for addressing global warming and the global energy crisis. In many CHP technologies, the Stirling engine is outstanding since it has the advantage of various energy sources such as solar, geothermal, and industrial heat waste. The regenerator plays a key role in building a high efficiency Stirling Engine. Since it works as an energy storage component in the Stirling engine, its performance directly affects the Stirling engine efficiency. In the previous research, a new regenerator called the robust foil regenerator was designed to improve the performance of the regenerator. The regenerator was manufactured through the method of additive manufacturing techniques since the thickness of each flow channel is 0.3mm. In this research, a test bench was designed and manufactured to reveal the characteristics of the regenerator experimentally. By measuring the pressure drop and the temperature difference through the regenerator, the friction coefficient and the Nusselt number correlations were derived respectively. These correlations were compared to the published friction factor and Nusselt number correlations. In addition, to evaluate the geometrical configuration of the regenerator, the NPH/NTU ratio was calculated using the derived friction coefficient and Nusselt number.