Assessment of Stirling Engine Based Air Independent Propulsion Systems in Submarines

In the defense forces of countries, especially the navy forces have an important place. Submarines are the cornerstone of naval forces and it has been effectively demonstrated how important a power it was in World War II. Since then, technological developments in submarines have accelerated considerably. Undoubtedly, the developments made in the propulsion systems are at the forefront of the mentioned developments. Especially with the use of AIP (Air Independent Propulsion Systems) systems, a rapid development has been observed. Many variants are applied, from classical diesel-electric submarines to closed-cycle submarines with fuel-cell technology to stirling-based submarines. Submarine applications of stirling engines, which are also used in the navies of developed countries such as Sweden and Japan, stand out. The main advantages of Stirling engines are lower refueling costs compared to Fuel cells and being quieter than the MESMA system. In addition, the fact that the exhaust gas emission is more controlled compared to internal combustion engines is among the main reasons why it is preferred. The recent development of Stirling engines and the preference of NASA's radioisotope vehicle as the main power source show how efficient the engine is without the need for oxygen and its maintenance requirement is at a minimum level. In this article, it will be discussed how the stirling engine has been developed until today and why it is preferred in submarine applications, its advantages and its future.