Development of an experimental test rig for cogeneration based on a Stirling engine and a biofuel burner

Abstract

A system consisting of a last-generation Stirling engine (SE) and a fuel burner for distributed power generation has been developed and experimentally investigated. The heat generated by the combustion of two liquid fuels, a standard Diesel fuel and a rapeseed oil, is used as a heat source for the SE, that converts part of the thermal energy into mechanical and then electric energy. The hot head of the SE is kept in direct contact with the flame generated by the burner. The burner operating parameters, designed for Diesel fuel, were changed to make it possible to burn vegetable oils, not suitable for internal combustion engines. The possibility of adopting different configurations of the combustion chamber was taken into account to increase the system efficiency. The preliminary configurations adopted allowed to operate this integrated system, obtaining an electric power up to 4.4 kW el with a net efficiency of 11.6%.

Performance improvements in Stirling cycle machines by a modified appendix gap geometry

“…Regenerative cycles, such as the well‐known Stirling cycle, may utilize and transform virtually any heat flow, particularly including heat from various renewable sources, and may thus contribute to the global energy transformation. Therefore, they are increasingly under consideration for micro‐cogeneration applications 1‐4 and particularly for utilizing various forms of biomass 5‐11 as well as solar energy 12‐15 . However, the performance of the idealized, theoretically reversible cycles is in practice degraded by a variety of loss mechanisms.…”

Comparative Study of Electric Machines for Stirling Generator Application

“…Many authors develop some models to increase the efficiency of Stirling generators for different applications. These include cogeneration [2][3][4][5][6], the conversion of exhaust gas heat into electricity [7][8][9], the recovery of biomass [10][11][12][13], the conversion of solar energy into electricity [14][15][16][17], the dual use of heat for cooking and lighting [18]. In references [19] and [20], since the output frequency of the Stirling engine is low, authors develop a model to improve the performance of the regenerator and the hot head of the heat engine to increase the final speed.…”