Stirling engines have either 2 pistons in 2 cylinders or 2 pistons in a single cylinder, with the heater, regenerator and cooler installed between the pistons. The single piston type Stirling engine, on the other hand, consists of a single piston in a single cylinder, a cooler, a regenerator, a heater and a gas damper. The gas damper has a role equivalent to the expansion piston. For this research, in order to examine the effect of external and internal heating on the engine performance, a simple prototype engine using air at normal atmospheric pressure as the working gas, was fabricated. Effects of heating methods on the engine performance were examined experimentally. In addition, based on the external heating engine performance examined, the pressurized engine using helium at 1MPa as the working gas was designed and manufactured.

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Flow resistance, heat transfer and indicated work were measured for a high performance model Stirling engine. Flow resistance was measured for Stacks of honeycomb plates and of metal gauzes. Flow resistance for honeycomb plate was correlated with Uchida's analytical solution with a 1.2 factor. That for wire gauze was roughly doubled. Compression and expansion were carried out almost adiabatically. Heat transfer in isometric heating and cooling was comparable to that calculated for an isothermal model. In spite of low heat transfer on compression and expansion, indicated work corresponds to that calculated with isothermal model.

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In this paper, research and develop the stirling engine of the small high power for the purpose of the exhaust heat recovery. We became multi cylinders to collect the exhaust heat from a factory and a biomass fuel and designed the downsized engine. This engine achieved shaft power 100[W] by simulation. We produce a trial manufacture engine based on simulation and perform the power measurement of the actual engine and compare it with the simulation. Furthermore, inspect a special cylinder and the usefulness about the piston using for this engine.

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The purpose of this study is the performance enhancement of the double acting type (DA type) six cylinder stirling engine. The conventional piston ring used the ring which combined an endless piston ring with a straight cut ring. The new piston ring incorporated the expander ring in conventional ones. As a result of experiment, some shaft output improved. The optlmization of the expander ring was proved to be importnt for further output improvement.

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Stirling engine power would increase if dead volume that decreased pressure amplitude of working gas is not contained in the engine. In this study, output performance is rose by diminishing the dead volume. As an improvement, fitting up stopper in the engine have decreased the dead volume. So, alteration of engine power was studied by comparison of stopper and without stopper in the engine from experiment. Finally, reading a paper on the result.

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In this study, we work on the development of the stirling engine which we can put on the model car of the 1/10 scale. We decided to pressurize the gas because miniaturization of the size and enhancing of the engine output were needed. To pressurize the engine, we devised to seal the crankcase and to generate electricity in this crankcase. Moreover, the torque variation decreases by combining two sets of the a type engines that the each phase angle differences are 90 degree. The diameter of the flywheel can miniaturize, too. This report shows the characteristic of the engine which we designed and a calculation result of the theoretical output.

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KAIHO Engine is a new external combustion engine having following features; (1)Can use solid disposal biomass as the fuel directly, and all combustion gas generated can be used for heating the working gas(N_2), (2)Is consisted of pressure difference generator(PDG), power piston(PP), heater, regenerator, cooler, Separated each other, connected by pipes. The size of the heater, regenerator, cooler are not restricted. The operating principle of this engine is that PDG generates output and pressure difference between the heater and the cooler simultaneously. The pressure difference generated drives the power piston. The experiment was performed to prove validity of the principle and to grasp the output performance of the engine. The fomer was proved, but the output was remained at 2kW, not able to reach the goal of 20kW. The reason the output remained short was investigated. It was found out that it was due to the very short delay of the non-return valve to open, which was used for the intake valve of the low temperature cylinder of the PDG, due to the inertia of its plug. A new valve system without the delay was developed and tested.

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We have now developed a new α^+-type engine that is considered about higher buffer pressure and higher engine speed. Note that the α^+-type mechanism is suitable for low-temperature-difference Stirling engines and the α^+-type engine has a mechanism that is possible to use a regenerator with a sufficiently large area without large load applied to the crankshaft. The α^+-type engine is most effectively applied to power generation using combined solar heat and combustion heat from a wood biomass because the engine can be driven by indirect heating using 300 degC thermal oils. We report the plan, design and manufacturing first machine of new 10 kW class engine that reduces size of half.

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We had designed and prototyped original 4-cylinder opposed-piston gamma-type circulating flow Stirling engine (CFSE) with lead valves, 2-stage large heater for waste heat recovering from rectangular duct of hot gas flow. Prospected output is 7.5kW-e by IPM generator. This kinetic design has an advantage of compact, low vibration and high rotational speed. Main materials of cylinder, casing, manifold and piston are made by sand cast of AC4C-T6 or SCS13. Heater part of large heat transfer is composed by vended stainless fin tube of form rolling. Those engineering trials using reasonable materials and process are very important for mass-production of low cost and distribution to the market.

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From viewpoints of energy saving and environmental problem, a LNG fueled ship is noticed in the marine field. The LNG (Liquid Natural Gas) is needed to vaporize in the ship. The LNG fueled ship will have a vaporizer and a reliquefaction device into the fuel line. In order to discuss the Stirling engine application for the LNG fueled ship, we have tested and measured the performance of heat pump and refrigerating operations using a 500 W class experimental Stirling engine generator system.

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From a viewpoint of the prevention from warming, reduction of CO_2 emissions is called for and the exhaust-heat recovery technology in a factory or a car attracts attention in recent years. Its attention was paid to the free piston Stirling engine with few moving parts as an example of the technology. A linear alternator is used when an output piston takes out the output of the engine which carries out a both-way straight-line motion as electric power. In order for this linear alternator to be operated efficiently, control of an eddy current becomes important. In this research, the lamination method of an electromagnetic plate has been improved, improvement in a generate output was aimed at in the simplest possible form, and the effect was checked in a simulation and an experiment.

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Free piston Stirling engine (FPSE) converters have been developed as heat-to-electricity power converters for future aerospace applications at the Japan Aerospace Exploration Agency. In the case of FPSE, the linear alternator is one of the most important converter components, because its characteristics govern the performance of the Stirling power converter, Therefore, as a part of the project, many types of linear alternator have been designed, fabricated and tested. The target power outputs of these altemators ranged from less than 10 W to 1kW electricity at the rated operational frequencies from 35 to 70Hz. Based on these achievements, this paper details the design methodology of the high efficiency linear alternator for FPSE and test results of the prototype models. Furthermore, a new application of linear alternator technology is described.

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The adsorption force between two objects is caused by various factors such as surface condition and static electricity. At the surface of the displacer cylinder inside of the γ type stirling engine, if an adsorption force between the cylinder and the piston is increases, the output of the engine is decrease. There is a gap between the cylinder and the piston to avoid the collision at a top or a bottom dead center. These gaps are the invalid capacities causing the output decline. If to clarify a maximum distance that an adsorption force acts on, it can design closer the gap in the displacer cylinder. This report shows experimentally the adsorption force to act on the wall surfaces such as the displacer piston and the cylinder.

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Double-acting type (DA type) six cylinder Stirling engine is researched to raise the performance characteristic. On account of get a quantitative evaluation of cooler performance, thermocouple was mounted between cooler and regenerator for temperature measurement. Therefore, mounting thermocouple allowed measuring temperature of the working gas passage double-ended of cooler. The coefficient of overall heat transmission κ was able to calculate value as showing the cooler performance. In this study, we report the compared result about performance of the leak-free cooler obtained by experiment.

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A waste heat recovery Stirling engine has lower working temperature level and lower thermal efficiency than a high-performance Stirling engine with combustion gas as the heat source. Therefore, the cooler should have enough rejected heat performance. When the cooler does not have enough performance, the compression space gas temperature becomes high, and the power becomes low. In this paper, the authors present operating results using several types of the cooler with a 500 W class Stirling engine. Then the thermal performance of the coolers is discussed with the comparison of the test results and calculated results.

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As a power source for emergency power supply, a Stirling engine has received keen interest due to its high thermal efficiency as well as its fuel diversity. In this study, a tubular flame burner has been developed for heating the head of a Stirling engine. To avoid flame flashback rapidly-mixed type tubular flame burner, in which fuel and oxidizer are separately injected, has been adopted. The fuel used is a biogas, which consists of 60% methane and 40% carbon dioxide by volume. Results show that stable combustion can be obtained for a wide range in equivalence ratio and in heat input. With a decrease of equivalence ratio, the head temperature, electric power generation and thermal efficiency are increased for a constant heat input, and a maximum thermal efficiency of about 8% has been achieved.

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Aiming at reduction of the energy consumed in domestic use and business use, research of an energy system corresponding to ZEB/ZEH is advanced. The authers are developing a hybrid heat source Stirling engine CHP system, which uses solar and woody biomass for a heat source, and supplies power generation and warm water. A solar concentrator is made by a Fresnel lens. The Sirling engine generator has a power generation output of 200W. Arter performing characteristic examination with them from now on, a solar Stirling engine power generation system is setting up as a base system, and performance evaluation is conducted.

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Global warming and exhaustion of fossil fuels are caused by mass consumption of fossil fuel, and they have become worldwide problems. A small co-generation system fueled wood pellets for greenhouse are focused in order to solve these problems. Therefore, this co-generation system with Stirling engine was developed to evaluate its perfomance for three elements of a combustor, Stirling engine, and three kinds of wood pellet. As the results, the combustor was supplied with about 90% heat of pellets in this experiment. The maximum power electric-generating capacity was 165W in this experiment, and the total energy efficiency was 49% with 6.8kW of total heat recovery. Many ashes from bark pellets were found on a fire grate of combustor after this experiment. it was necessary to remove ashes fom the fire grate at work frequentry.

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Woody Biomass is defined as a new energy and desired to utilize an energy source beneficially. The authors present a power generation system constructed by a firewood boiler and a Stirling engine generator, The firewood boiler using gasification combustion has a maximum incineration capacity of 20kg/h and a power consumption of 400W. The Stirling engine generator is built up as a 2 piston type engine with driving mechanism including a PM synchronous generator. It is installed in a secondary combustion chamber of the firewood boiler and heated by combustion gas. This paper describes the examination results of the system using a firewood of Japanese oak as fuel. The power generation of 534W and the heat supply capacity of 33.6kW are obtained.

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A thermoacoustic engine electric generator should generate some electrical power from supplied heat if the equivalent acoustic impedance of the electric generator coincides with the acoustic impedance of the thermoacoustic engine at a certain frequency. In order to build such a thermoacoustic device, we measure the mechanical impedance of a voice coil motor and design a thermoacoustic engine which has proper acoustic impedance by numerical calculation based on thermoacoustic theory.

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According to Ceperley's calculation, if acoustic impedance z at the position of the regenerator is equal to ρ_mc, the efficiency is limited to 10% of second law efficiency η_2 due to viscous losses in the regenerator. Higher efficiency is possible with higher impedance, e.g., if z=10ρ_mc, η_2 reaches 79%. In order to achieve z=10ρ_mc, he explained the cross-sectional area of the enlarged tube would have to be 10 times larger. than that of the input tube. In this report, we changed the cross sectional area of the regenerator so it is larger than that of resonator, and measured its thermal efficiency and acoustic power gain at regenerator positions of a traveling wave heat engine.

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Radiation is paid attention as the optimum heat input method for the thermoacoustic phenomenon since the conventional heat input method is inefficient. The thermoacoustic prime mover driven by sunlight was developed. The sunlight collected by the parabolic thermal collector was introduced to the stack directly from many directions. Four kinds of stack that are different from materials and duct shapes ware evaluated with the onset temperature, the stationary temperature and the pressure of the generated acoustic wave. In case of using radiation, thus, the stack with low flow resistance and high specific surface area is required.

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For the purpose of cooling high-temperature superconductor (HTS) devices, such as superconductor motors, SMES and current fault limiters, cryocoolers should be compact in size, light-weight, and have high efficiency and high reliability. In order to meet the demand of HTS devices world-wide, the cryocooler needs to have COP efficiency >0.1. We have developed a high power Stirling-type pulse tube cryocooler (SPTC) with an inline expander. The cooling capacity was 210W at 77K and the minimum temperature was 37K when the compressor input power was 3.8kW. Accordingly, the COP was about 0.055. To further improve the efficiency, the energy losses in the cryocooler were analyzed. The experimental results and the numerical calculation results are reported in this paper.

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Thermoacoustic phenomenon is the energy conversion between heat and sound. At the prime mover of thermoacoustic system, temperature difference between the heater and environments is converted to the acoustic wave. But there are unclear points in the process of the energy conversion from heat to sound. To understand how this occurs, self-excited oscillation between parallel plates is visualized with CW laser and high-speed camera. The relation of the fluctuation of pressure, velocity and displacement are revealed from the view point of fluid dynamics by visualizing in flow channel parallel-plate stack with Particle Imaging Velocimetry (PIV).

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We measure the temperature required to drive a thermoacoustic engine and compare containing only air with containing air, water vapor, and liquid water as the working fluids. The oscillation temperature in the case of containing dry air is measured to be 134℃ whereas in the case of containing wet air is measured to be 67℃. Moreover, the results of a measurement of the pressure amplitude in air with a dry stack and with a stack wetted with water provide the acoustic power with a wet stack at the same level as with a dry stack.

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Numerical simulation of heat and fluid flow has been performed to estimate the value of time-averaged heat transfer coefficient between the working gas and the wall in oscillatory flows. Transient two-dimensional equations of continuity, momentum and energy were solved utilizing a TVD scheme. A physical model of a simple circular tube was used for the numerical simulation. In this study, the value of heat transfer coefficient in a heat exchanger was clarified by analyzing the numerical results of the two-dimensional simulation.

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