The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Yoshiaki Watanabe - One of the best experts on this subject based on the ideXlab platform.
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effect of the relative installation position of two enlarged Prime Movers on the onset temperature in loop tube type multistage thermoacoustic system
Japanese Journal of Applied Physics, 2015Co-Authors: Tatsuya Ishino, Yoshitaka Inui, Shinichi Sakamoto, Yuichiro Orino, Yoshiaki WatanabeAbstract:Reducing the driving temperature of a thermoacoustic system to effectively utilize the unused low-temperature heat source is important for improving the performance of the system. The driving temperature of the thermoacoustic system was reduced by installing multiple stages of Prime Movers in series, a heat-to-sound transducer, and a Prime Mover with an increased cross-sectional area. In this study, the oscillation temperature was investigated both experimentally and by stability analysis in order to verify whether the system is operable, and to determine its operating temperature, when changing the installation position of the two-stage Prime Mover with increased cross-sectional area.
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measurement of temperature gradient in a stack of a Prime Mover in a loop tube type thermoacoustic cooling system
NONLINEAR ACOUSTICS STATE-OF-THE-ART AND PERSPECTIVES: 19th International Symposium on Nonlinear Acoustics, 2012Co-Authors: Shinichi Sakamoto, Yoshitaka Inui, Yoshiaki WatanabeAbstract:This paper specifically describes spatial and temporal variation of the temperature gradient in a stack of a Prime Mover in a loop-tube-type thermoacoustic cooling system. Spatial and temporal variations in the temperature gradient were measured for various stack lengths. Measurements were also conducted in cases with and without self-sustained sound. Because the thermal and viscous boundary-layer thicknesses depend on the temperature, detailed knowledge of spatial and temporal variations of the temperature gradient in the stack will be important to design a stack, especially in terms of the stack channel radius. Because little has been reported about the temperature gradient formed in the stack, the results obtained in these experiments are expected to contribute to improvement of the cooling effect of thermoacoustic cooling systems. Observations of the temperature variation in cases with and without self-sustained sound in the loop-tube confirmed that with self-sustained sound, a temperature gradient is...
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effect of inner diameter change of phase adjuster on heat to sound energy conversion efficiency in loop tube type thermoacoustic Prime Mover
Japanese Journal of Applied Physics, 2008Co-Authors: Shinichi Sakamoto, Takahiro Ishino, Yoshiaki Watanabe, Masahiro Nishikawa, Jiro SendaAbstract:The use of a phase adjuster (PA) has been proposed to improve the cooling effect of a loop-tube-type thermoacoustic cooling system. A PA is a device for increasing the particle velocity of sound by narrowing a part of the loop tube. In this experiment, we present a discussion of the efficiency of heat-to-sound energy conversion in a loop-tube-type thermoacoustic Prime Mover, particularly emphasizing on the inner diameter change of PA. It is found that the sound pressure is higher for larger inner diameter; the particle velocity is higher for larger inner diameter and the phase difference between the sound pressure and the particle velocity is bigger for larger inner diameter. It is also found that sound intensity is different according to the inner diameter, and that it is higher for larger inner diameter. Results obtained confirm that PA improves the efficiency of heat-to-sound energy conversion in the loop-tube-type thermoacoustic Prime Mover, and that the efficiency depends on the inner diameter of PA.
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reduction in temperature difference of Prime Mover stack in loop tube type thermoacoustic cooling system by applying phase adjuster
Japanese Journal of Applied Physics, 2008Co-Authors: Shinichi Sakamoto, Yoshiaki WatanabeAbstract:The use of a phase adjuster (PA) is proposed to reduce the temperature difference between the upper and lower ends of the Prime Mover stack in a loop-tube-type thermoacoustic cooling system. PA is a device for increasing particle velocity. By placing PA in the loop tube, the resonance is forcibly one wavelength. It is confirmed that the temperature difference of the Prime Mover stack with PA is smaller than that without PA. Because PA prevents the resonance wavelength shift from one-wavelength resonance to two-wavelength resonance, the loop tube suppresses the increase in temperature at the Prime Mover stack, so that the viscous boundary layer thickness is smaller than the stack channel radius. This induces an effective energy conversion. Consequently, the temperature difference is reduced.
K.f. Fong - One of the best experts on this subject based on the ideXlab platform.
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investigation on part load performances of combined cooling and power system Primed by solid oxide fuel cell with different bottoming cycles
Journal of Power Sources, 2019Co-Authors: X J Luo, K.f. FongAbstract:Abstract In hot-humid cities, conventional trigeneration can be reduced to combined cooling and power system. Solid oxide fuel cell is a high-temperature Prime Mover with high electrical efficiency, its efficiency may be further boosted up with bottoming cycle like gas turbine, Stirling engine and organic Rankine cycle. Besides using waste heat recovered from the Prime Mover to energize absorption chiller, the surplus electricity can be used to drive the conventional compression chiller as supplement. However, there is little knowledge about the effectiveness of such combined cooling and power system under different operating conditions. System models with various bottoming cycles are therefore developed, and their part-load performances are investigated. The effects of fuel inlet temperature and current density of fuel cell stack; compression ratio of gas turbine; Stirling engine type; working fluid of organic Rankine cycle; and fuel cell stack part-load ratio are explored. It is found that the combined cooling and power system with bottoming cycles of gas turbine and Stirling engine have higher boost of electrical efficiency. Gas turbine bottoming cycle is recommended when building energy demands are relatively constant, while Stirling engine bottoming cycle is suggested for variable energy demands.
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dynamic performances of trigeneration systems using different Prime Movers for high rise building application a comparative study
Building Simulation, 2017Co-Authors: K.f. FongAbstract:Trigeneration is a strategic deployment to achieve the energy saving target in response to climate change mitigation. Appropriate choice of Prime Movers is paramount to make trigeneration feasible. It is common for trigeneration to be considered in district-wide application; however, there is little study on the effectiveness of various available Prime Movers in building-scale use. As such, diesel engine (DE), gas engine (GE), gas turbine with recuperator, and combined gas turbine cycle (CGTC) were involved as Prime Mover options for trigeneration in this study. Through year-round dynamic simulation, the energy and environmental performances of different trigeneration systems were thoroughly evaluated for a high-rise hotel building in subtropical climate. It was found that the DE-Primed trigeneration would have the highest primary energy saving, while the CGTC-Primed trigeneration would be the largest in carbon emissions cut. However, the GE-Primed trigeneration system was deemed to be the best choice with both energy merit and system simplicity. It was also found that the part-load performance of Prime Mover and the required fuel type were closely associated to the annual energy and environmental performances.
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Control Optimization of Combined Cooling and Power System with Prime Mover of Solid Oxide Fuel Cell-gas Turbine for Building Application
Energy Procedia, 2017Co-Authors: X J Luo, K.f. FongAbstract:This paper presents a control strategy for a combined cooling and power (CCP) system using a Prime Mover of solid oxide fuel cell (SOFC) with bottoming cycle of gas turbine (GT) for building application. Dynamic simulation model of the CCP system was developed in TRNSYS 17, and the control strategy was developed for year-round operation in response to the changing climatic and loading conditions. The capacity ratio of cells in operation; the ratio of exhaust heat delivered to GT; and the ratio of cooling load shared between absorption and compression chillers were chosen as the decision variables in the control strategy. In order to minimize the system energy consumption, particle swarm optimization (PSO) was constructed in MATLAB and coupled with TRNSYS 17 for control optimization. It was found that with the proposed control strategy, the yearly energy saving of the SOFC-GT CCP system would be 6.89% compared to the reference case.
Shinichi Sakamoto - One of the best experts on this subject based on the ideXlab platform.
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effect of the relative installation position of two enlarged Prime Movers on the onset temperature in loop tube type multistage thermoacoustic system
Japanese Journal of Applied Physics, 2015Co-Authors: Tatsuya Ishino, Yoshitaka Inui, Shinichi Sakamoto, Yuichiro Orino, Yoshiaki WatanabeAbstract:Reducing the driving temperature of a thermoacoustic system to effectively utilize the unused low-temperature heat source is important for improving the performance of the system. The driving temperature of the thermoacoustic system was reduced by installing multiple stages of Prime Movers in series, a heat-to-sound transducer, and a Prime Mover with an increased cross-sectional area. In this study, the oscillation temperature was investigated both experimentally and by stability analysis in order to verify whether the system is operable, and to determine its operating temperature, when changing the installation position of the two-stage Prime Mover with increased cross-sectional area.
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measurement of temperature gradient in a stack of a Prime Mover in a loop tube type thermoacoustic cooling system
NONLINEAR ACOUSTICS STATE-OF-THE-ART AND PERSPECTIVES: 19th International Symposium on Nonlinear Acoustics, 2012Co-Authors: Shinichi Sakamoto, Yoshitaka Inui, Yoshiaki WatanabeAbstract:This paper specifically describes spatial and temporal variation of the temperature gradient in a stack of a Prime Mover in a loop-tube-type thermoacoustic cooling system. Spatial and temporal variations in the temperature gradient were measured for various stack lengths. Measurements were also conducted in cases with and without self-sustained sound. Because the thermal and viscous boundary-layer thicknesses depend on the temperature, detailed knowledge of spatial and temporal variations of the temperature gradient in the stack will be important to design a stack, especially in terms of the stack channel radius. Because little has been reported about the temperature gradient formed in the stack, the results obtained in these experiments are expected to contribute to improvement of the cooling effect of thermoacoustic cooling systems. Observations of the temperature variation in cases with and without self-sustained sound in the loop-tube confirmed that with self-sustained sound, a temperature gradient is...
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effect of inner diameter change of phase adjuster on heat to sound energy conversion efficiency in loop tube type thermoacoustic Prime Mover
Japanese Journal of Applied Physics, 2008Co-Authors: Shinichi Sakamoto, Takahiro Ishino, Yoshiaki Watanabe, Masahiro Nishikawa, Jiro SendaAbstract:The use of a phase adjuster (PA) has been proposed to improve the cooling effect of a loop-tube-type thermoacoustic cooling system. A PA is a device for increasing the particle velocity of sound by narrowing a part of the loop tube. In this experiment, we present a discussion of the efficiency of heat-to-sound energy conversion in a loop-tube-type thermoacoustic Prime Mover, particularly emphasizing on the inner diameter change of PA. It is found that the sound pressure is higher for larger inner diameter; the particle velocity is higher for larger inner diameter and the phase difference between the sound pressure and the particle velocity is bigger for larger inner diameter. It is also found that sound intensity is different according to the inner diameter, and that it is higher for larger inner diameter. Results obtained confirm that PA improves the efficiency of heat-to-sound energy conversion in the loop-tube-type thermoacoustic Prime Mover, and that the efficiency depends on the inner diameter of PA.
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reduction in temperature difference of Prime Mover stack in loop tube type thermoacoustic cooling system by applying phase adjuster
Japanese Journal of Applied Physics, 2008Co-Authors: Shinichi Sakamoto, Yoshiaki WatanabeAbstract:The use of a phase adjuster (PA) is proposed to reduce the temperature difference between the upper and lower ends of the Prime Mover stack in a loop-tube-type thermoacoustic cooling system. PA is a device for increasing particle velocity. By placing PA in the loop tube, the resonance is forcibly one wavelength. It is confirmed that the temperature difference of the Prime Mover stack with PA is smaller than that without PA. Because PA prevents the resonance wavelength shift from one-wavelength resonance to two-wavelength resonance, the loop tube suppresses the increase in temperature at the Prime Mover stack, so that the viscous boundary layer thickness is smaller than the stack channel radius. This induces an effective energy conversion. Consequently, the temperature difference is reduced.
Taichi Yazaki - One of the best experts on this subject based on the ideXlab platform.
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measurements of acoustic streaming in a looped tube thermoacoustic engine with a jet pump
Journal of Applied Physics, 2007Co-Authors: Tetsushi Biwa, Yuki Ueda, Yusuke Tashiro, Masahiro Ishigaki, Taichi YazakiAbstract:This paper reports on the acoustic streaming in a looped-tube thermoacoustic Prime Mover equipped with an asymmetric constriction called a jet pump. The time-averaged mass flow velocity was determined using visualization methods and using acoustic field measurements. It was demonstrated that the magnitude and the direction of the velocity were dependent on the orientation of the jet pump. From the observed velocities, we estimated the heat carried away from the hot heat exchanger by the mass flow. It was shown that the heat loss was decreased from 30 W to 6.5 W by reversing the orientation of the jet pump, when the input heat power supplied to the Prime Mover was 100 W. The influence of the acoustic streaming was also studied from the cooling temperature of the looped-tube cooler.
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experimental studies of a thermoacoustic stirling Prime Mover and its application to a cooler
Journal of the Acoustical Society of America, 2004Co-Authors: Yuki Ueda, Tetsushi Biwa, Uichiro Mizutani, Taichi YazakiAbstract:An acoustic field spontaneously induced in a thermoacoustic Prime Mover consisting of a looped tube and resonator is determined through simultaneously measurements of pressure P and velocity U. A thermal efficiency of the thermoacoustic Prime Mover of this type has been reported to reach 30%. The measurements of the acoustic field in the present system revealed that a phase lead of U relative to P takes a negative value of about −20° in the regenerator where the output power of the Prime Mover is generated. It was concluded that the possession of a negative phase lead at this position is taken as a clue in a significant increase in the output power. Moreover, the analysis in the thermoacoustic mechanism shows that a precise position for the location of a second regenerator acting as a heat pump exists in the looped tube. Indeed, by locating the second regenerator at the position, a thermoacoustic cooler was constructed. The thermoacoustic cooler could generate a low temperature of −25 °C without involving any moving parts.
S Kasthurirengan - One of the best experts on this subject based on the ideXlab platform.
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studies on performance of thermoacoustic Prime Mover
Experimental Heat Transfer, 2015Co-Authors: N M Hariharan, P Sivashanmugam, S KasthurirenganAbstract:Thermoacoustic engines are the devices that convert thermal energy into acoustic energy without moving parts. The main objective of this study is to analyze the performance of a thermoacoustic Prime Mover measured in terms of onset temperature difference, frequency, and pressure amplitude by varying resonator, stack length, and plate thickness. From the experiments, it is observed that onset temperature difference and pressure amplitude increases with increase in resonator and stack length with minimum plate thickness, whereas the frequency increases with decrease in resonator and stack length with higher plate thickness. The experimental results are compared with simulated results via Design Environment for Low Amplitude Thermoacoustic Energy Conversion software (Los Alamos National Laboratory, Los Alamos, New Mexico, USA).
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experimental investigation of a thermoacoustic refrigerator driven by a standing wave twin thermoacoustic Prime Mover
International Journal of Refrigeration-revue Internationale Du Froid, 2013Co-Authors: N M Hariharan, P Sivashanmugam, S KasthurirenganAbstract:The objective of this study is to analyse the performance of thermoacoustic refrigerator (TAR) measured in terms of hot end temperature and temperature difference across refrigerator stack with two different spacing namely 0.4 mm and 0.8 mm and stack used in refrigerating section was made of low thermal conductivity materials namely Mylar sheet and photographic film & the experiments were carried out at 1 MPa pressure using helium as working fluid. High powered acoustic wave with frequency of 460 Hz and pressure amplitude of congruent to 0.07 MPa was obtained from twin thermoacoustic Prime Mover (TAPM) and this acoustic wave produced temperature difference of 16 degrees C across the Mylar sheet stack made of 0.4 mm spacing in refrigerator section. From this study, it has been inferred that twin TAPM can act as efficient drive for TAR. (C) 2013 Elsevier Ltd and IIR. All rights reserved.
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influence of working fluid on the performance of a standing wave thermoacoustic Prime Mover
Cryogenics, 2011Co-Authors: Yonglin Ju, Upendra Behera, S Kasthurirengan, S KasthurirenganAbstract:The thermoacoustic Prime Mover (TAPM) is an attractive alternative as a pressure wave generator to drive Pulse Tube Cryocoolers (PTCs), by the absence of moving parts, construction simplicity, reasonable efficiency, and environmental friendly. Decreasing the resonance frequency and improving the efficiency of the TAPM are important to drive the PTCs. These are controlled by the working gas parameters other than the dimensions of TAPM. In this technical note, the experimental studies carried out to evaluate the influence of different working fluids on the performances of a twin standing wave TAPM at various operating pressures have been compared with the simulation studies of the same system using DeltaEc wherever possible. The reasonably good agreement between them indicates the utility of DeltaEc for the optimal design of TAPM with the right working fluids for practical applications.
