Hiroichi Watanabe

New solar Stirling engine TNT-1 with direct internal radiation heating

A unique 1 kW solar Stirling engine called TNT-1 (for Tohoku Gakuin Univ., Nihon Univ., and Tohoku Electric Power), utilizing N. Isshikis (1984) internal solar heating method and two solar concentrator dishes, is under test as a prototype for future large-scale solar engine systems. The Stirling engine has a transparent cylinder head made of quartz glass, and the solar beam concentrated by the solar dish heats up internal meshes installed on the displacer directly from the outside through the glass. As a result the engine can have a very simple heater with small dead volume and with enough heating surface, using wire mesh only, to provide high efficiency and low cost. One solar dish is a very accurate parabolic concentrator consisting of 180 small, accurate glass mirrors; the other consists of 40 simple spherical mirrors composed of plastic plates.<<ETX>>

Characteristics of Stirling engine regenerator

The performance of the Stirling engine is influenced by the performance of the regenerator. Over 98% for the regeneration efficiency of the Regenerator must be made with the goal so that the thermal efficiency of the Stirling engine may achieve over 30%. Though the regeneration efficiency is improved as the volume of the regenerator is increased, and as the area of the heating surface is increased, on the other hand as the pressure loss of the inside increases, the output of the engine is lowered. Experiments to examine the characteristics of Stirling engine regenerators are described by the authors.

Regenerative rotary displacer Stirling engine

A few rotary displacer Stirling engines whose displacers have one gas pocket space at one side, and rotate in a main enclosed cylinder, which is heated from one side and cooled from the opposite side without any regenerator have been tried and studied for a considerable time by the authors. They then tried to improve this engine by equipping them with regenerators, because without regenerators, pressure oscillation and efficiency are insufficient. Here, several types of regenerative rotary displacer piston Stirling engines are proposed. One is the contra-rotating tandem two disc-type displacer engine, using axial heat conduction through side walls or by heat pipes and the other are single disc-types with circulating fluid regenerators or heat pipes. A contra-rotating type engine has been manufactured and experimented upon in order to assess the effect of the regenerators. Here, experimental results of an original rotary displacer Stirling engine without a regenerator and a contra-rotating tandem displacer engine with a side wall regenerator using axial heat conduction are reported, accompanied by many discussions.

STUDIED OF RECYCLED FUEL OIL FOR DIESEL ENGINE EXTRACTED FROM WASTE PLASTICS DISPOSALS ( Case of the Cracked PE Oil )

In developed countries there are so many discarded plastic disposals from various kinds industry and cities. One of authors company ( Ecology System ) has developed a new recycle system and apparatus to liquefy these plastic disposals into fuel oils. These discarded plastic are melted and evaporated first, and their vapors are condensed and extracted after passing through various metal catalyzers for decomposition. The recycled oils are different one by one according to the kind of raw plastic, and generally it has high heating value with rather big density, and their total weight are about 60-80 % of raw plastics. The recycled oils are fed to Diesel engines of several factories as a 30-40% blended fuels with gas oil. Recycle of plastics by this method above will be very good contribution to energy and environments of the earth. In this paper is showed used of the Cracked PE ( Polyethylene) blending oil for engine performance.

Experimental studies on atmospheric Stirling engine NAS-2

Atmospheric hot air Stirling engines NAS-1 and 2 have a simple flat rubber sheet diaphragm as their power piston, and have been experimentally studied at Nihon University, Japan, for several years continuously, with the target of obtaining more than 100 watts shaft power by atmospheric air with simple construction and cheap materials. The first NAS-1 was intended to be a solar heated engine using television glass and wood for cheap cost, but it failed by thermal breaking of glass, so the improved NAS-2 has changed to be heated by a gas burner, using metallic materials in all parts except for the rubber power piston. Other than this rubber sheet diaphragm, NAS-2 has many features such as using the James Watt crank mechanism, highly finned copper tubes for conventional commercial heat exchangers and two kinds of hot gas heaters. The thickness of the power piston rubber sheet was gradually changed from 2 mm to 6 mm in order to determine which thickness was best; it was found that about 5 mm is best for this engine. After trying many improvements on this engine, NAS-2 has produced about 130 watt shaft power an with indicated power of 350 watt at 1994. In this paper, details of many features, history, results and experiments carried out these NAS Stirling engines are reported.

Kilowatt-Range Optical System for Driving the Solar Stirling Engine

The Cassegranian-type optical system for driving the solar Stirling engine consisted of a parabolic mirror with a diameter (D) of 3.2m and a hyperbolic mirror with a D of 600mm. The parabolic mirror was of the segmental-type which consisted of 180 ellipsoidal mirrors made from glass plates, and the hyperbolic mirror was made from Al plate. The Stirling engine was developed by Isshiki et al in order to convert solar heat energy into electric power. For driving this Stirling engine, the cylinder head was directly heated by the sun rays converged by this optical system, and the temperature of the cylinder increased up to 700 /spl deg/C. Finally, the engine produced an output power of about 1kW.

Kilowatt-range optical system for driving the solar Stirling engine

The optical systei for driving the solar Stirling engine with an output power in the kW range is described. This systei was of the Cassegranian-type and consisted of a parabolic iirror (diaieter 0 2. f/D 30 f: focal length) and a hyperbolic irror (0 . f/D 26). The parabolic airror was co. posed of 181 segiental iirrors . ade fro. glass plates and the hyperbolic iirror was iade fro. Al plate. The Stirling engine was developed by Isshiki et al. The input power of sun rays converged by the optical syste. ranged fro. 3. 0 to 3. 2kW and the output power of this engine was about 1kW. Fig. 1 The optical systea for the kW-range Fig. 2 A section of the Stirling engine. 1.