2025 年 20 巻 1 号 p. 24-00388
In recent years, industrial boilers that generate power from biomass have drawn a lot of attention. Nevertheless, a sizable portion of thermal energy is frequently lost to the environment as flue gas throughout the process. Stirling engine: a very efficient external combustion engine and little emissions as compared to other available engines, would be a good solution to overcome this issue as it can be used with any type of heat source. When the Stirling engine is connected to a heat source with a lower temperature, it exhibits a significant reduction in performance. Consequently, in this study a computational fluid dynamic (CFD) simulation model of Stirling engine was introduced in order to evaluate the possibility of recovering low temperature waste heat from biomass combustion. It has been shown to be effective in delivering useful, comprehensive information for further improvement of the engine. Then further parametric analysis will be investigated to enhance the engine’s performance. The investigation involving waste heat from wood pellets, coconut husk and bagasse as heat source then demonstrates the engine’s ability to recover and utilize heat as low as 70°C and generate power output ranging from 30 to 40 W and thermal efficiency of around 14%. Parametric analysis using different regenerator porosities, engine speeds and working fluid gases were also carried out to determine the optimal Stirling engine’s performance. The results demonstrate optimum performance at 0.85-0.9 of porosity and engine speed of 700 rpm and above. Overall, the results showed promising outcomes of Stirling engine to recover low temperature heat from biomass.
