Proposal of Steam Super Stirling Engine fit to Marine Use
Naotsugu ISSHIKI* Hiroshi KOJIMA** and Seita ISSHIKl***
The "Steam Super Stirling Engine (SSSE) is a Stirling engine assisted by steam injection. Near the top dead center of the power piston, saturated steam of 0.2〜2.0 Mpa pressure range is injected into the cold side of the displacers cylinder and the steam expands into power cylinder at high temperature after passing regenerator and heater. At bottom dead center of the power piston, the steam is ejected to outside as low-pressure and low temperature steam after passing the regenerator again. So, this engine works in the combination of Stirling cycle and steam Rankine cycle.
For marine use, condenser can be easily equipped, so that this engine well fits to ships and boats, with high efficiency and with any kind of fuels.
For example, woods or agricultural biomass or solar heat would be used for inland waterways.
Key Words: ISME 2000, Steam Engine, Stirling Engine, Combined Cycle
This is a proposal of new steam engine fit to marine use and which can use any kind of heat sources, and this ship will be used in land water ways, or incoming future possible energy crisis.
The illustration of the principle of this engine at double expansion of marine case is shown at Fig.1. Also, p-v diagram of this type is shown at Fig. 2 which shows that main parts of this engine work at hybrid of Stirling and Rankine cycles.
It is possible to make many other variations for this engine. Until today very small size engines of this type of double expansion, and steam experiments were done on land using 0.2Mpa air and steam, and about 50watt output were measured which value is several times higher than usual atmospheric Stirling engine of the same size.
If steam condenser is used to this engine, thermal efficiency and power are thought to be increased very much, so this engine can be said to be new steam engine fits to small size marine use, which has many points better than classic high pressure Helium Stirling engines.
By the results of many studies until today in room laboratories the following merits of this engine were cleared well.
(1) Power increases up to several times of conventional atmospheric Stirling engines.
(2) This engine needs no Helium gas, but it use H2O which molecule is light weight and cheap.
(3) Nearly no conventional cooling system of Stirling engine is needed except condenser.
(4) Weight of this engine is very small compared to conventional high pressure Stirling engine. So, this engine can be manufactured at low cost.
(5) Thermal efficiency of this engine is higher than conventional steam engine, although it is lower than original Stirling engine of the same high temperature, so that it is just in between of the two cycles.
*Prof. Emeritus of Tokyo Inst of Tech.
2-29-6 Kyodo Setagaya Tokyo 156-0052
**Maeta Techno-Research Inc.
***Fukushima National College of Technology.