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Search Results: 1 - 10 of 240 matches for " Takehiro Esaki "
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Reaction Rate Characteristics of SrBr2 Hydration System for Chemical Heat Pump Cooling Mode  [PDF]
Takehiro Esaki, Noriyuki Kobayashi
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.42012
Abstract: Here, we propose a chemical heat pump chiller with a SrBr2 hydration reaction system for utilization of waste heat. The SrBr2 hydration reaction could recover waste heat in low temperatures ranging from 373 K to 353 K, and the system showed good potential in terms of the high cooling thermal-storage density. Previous studies have given little information on the reaction characteristics of the SrBr2 hydration reaction. In this paper, we developed a measuring method for the hydration reaction equilibrium and reaction rate based on the volumetric method. We analyzed the hydration reaction rate with an unreacted-core shell model. In the experiments, the SrBr2 equilibrium temperature observed was equal to the theoretical equilibrium temperature obtained from thermodynamic databases. In addition, the hysteresis gap between the hydration and dehydration values was 2.0 K. Thus, the hysteresis effect was negligible for the chemical heat pump cooling operation. The reaction fraction of the SrBr2 hydration reached 0.7 within 20 s. By analyzing the hydration reaction rate with the unreacted-core shell model, the activation energy value was calculated to be56.6 kJ/mol. The calculation results showed good agreement with those of the experiment as the reaction fraction reached 0.7.
Evaluation of the Characteristic of Adsorption in a Double-Effect Adsorption Chiller with FAM-Z01  [PDF]
Takehiro Esaki, Noriyuki Kobayashi, Takayuki Matsuda
Journal of Materials Science and Chemical Engineering (MSCE) , 2016, DOI: 10.4236/msce.2016.410002
Abstract: Here, we propose a double-effect adsorption chiller with a zeolite adsorbent (FAM-Z01) for utilization of waste heat. The FAM-Z01 adsorbent has the potential to recover waste heat in low temperatures ranging from 353 to 333 K and shows good potential in the adsorption chiller in terms of the high cooling output. A double-effect adsorption chiller could provide a higher Coefficient Of Performance (COP) than that of a single-effect chiller. In this paper, we developed a measuring method for the amount of adsorption in the first and second adsorber in a double-effect adsorption chiller and measured the adsorption and desorption rate based on the volumetric method. We calculated the COP of the adsorption chiller with the quantity of adsorbent obtained in the experiment. In the experiments, the quantity of adsorbent in the first adsorber was 0.14 g-H2O/g-Ads at the pressure 20 kPa and a desorption temperature over 100. The amount of adsorbent in the second adsorber was equal to that of the first adsorber. By analyzing the COP with the experimental results, the COP value was calculated to be over 1.0 () at any desorption temperature. The COP of the double-effect cycle was higher than that of single-effect cycle.
Evaluation of Carbon Dioxide Absorption Characteristics Lithium Ortho-Silicate in Chemical Heat Storage  [PDF]
Takehiro Esaki, Daichi Iwase, Noriyuki Kobayashi
Journal of Materials Science and Chemical Engineering (MSCE) , 2017, DOI: 10.4236/msce.2017.54006
Abstract: We report the development of technology that may contribute to a reduction in greenhouse gas emissions and improve the energy efficiency of the CO2 capture process. Lithium ortho-silicate is a suitable solid sorbent for capturing CO2. This reversible chemical reaction is also applicable to chemical heat storage. The absorption reaction characteristics of lithium ortho-silicate were studied by a thermogravimetric method and a volumetric method that demonstrated the influence of heat and mass transfer limitations in a packed bed designed to be as small as possible. We developed a method for measuring the absorption reaction characteristics in the experiments. In the experiments, a constant conversion fraction of 60% was observed. The reaction system was stable to repetition. The CO2 absorption rate depends on the CO2 pressure and reactor temperature. The absorption rate was determined at several reactor temperatures when the conversion fraction was 0.3. In this study, the maximum absorption rate was obtained at 670oC. It was demonstrated that lithium ortho-silicate is suitable for use in a chemical heat storage system.
Evaluation of Performance of Thermal and Electrical Hybrid Adsorption Chiller Cycles with Mechanical Booster Pumps  [PDF]
Tao Zeng, Takehiro Esaki, Jun Li, Noriyuki Kobayashi, Hongyu Huang
Journal of Materials Science and Chemical Engineering (MSCE) , 2017, DOI: 10.4236/msce.2017.55003
Abstract: Large amounts of waste heat below 100oC from the industrial sector are re-leased into the atmosphere. It has been suggested that energy system efficiency can be increased with adsorption chillers. However, the cooling power and coefficient of performance (COP) of conventional adsorption chillers significantly decrease with the desorption temperature. In this paper, we proposed a mechanical booster pump (MBP)-assisted adsorption chiller cycle, and evaluated its performances. In the cycle, a MBP was incorporated into a zeolite-water-type adsorption chiller for facilitating water vapor transportation between an adsorber and an evaporator/condenser. We have experimentally studied the effect of the input electrical power of MBP on the performances of adsorption chiller cycle. It has been demonstrated that the heat input achieved by using MBP at the desorption temperature of 50oC was 1.6 times higher than that of without MBP at the desorption temperature of 60oC. And the increase of pump power was found to be effective in increasing the heat input. Therefore, it was confirmed that the operation range of desorption temperature, which can be generated by using the waste heat, was extended and the cooling power was increased directly by using MBP.
Characteristics of Absorption Equilibrium with HFC-134a and an Ionic Liquid Pair  [PDF]
Takehiro Esaki, Noriyuki Kobayashi, Hiroki Uchiyama, Yousuke Matsukuma
Journal of Materials Science and Chemical Engineering (MSCE) , 2019, DOI: 10.4236/msce.2019.73006
Abstract: Cold energy generation systems must be improved to prevent catastrophic climate change. In this study, we focused on an absorption chiller cycle with HFC-134a and an ionic liquid pair as the refrigerant and absorbent, respectively. It was expected that this absorption chiller cycle could generate cold heat below 0°C. Two liquids were selected and their absorption equilibrium with this pair was evaluated for the absorption chiller cycle. We measured the adsorbed amount at equilibrium with 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [BMIM][Tf2N] and N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide [N1113][Tf2N]. The experimental results were reproduced using the non-random two liquid (NRTL) model. This analysis model corresponded well in terms of the amount of adsorption at equilibrium with the experimental results. A Duhring diagram was also generated the NRTL model, and the absorption cycle characteristics as a function of temperature were determined. The absorption chiller cycle obtained cold heat at 10°C with a regeneration temperature of 70°C in addition to generating cold heat below 0°C.
Long-Term Durability and Reactivation of Thermochemical Heat Storage Driven by the CaO/Ca(OH)2 Reversible Reaction  [PDF]
Kazuki Kuwata, Takehiro Esaki, Daichi Iwase, Hiroyuki Ito, Shijie Li, Xixian Yang, Hongyu Huang, Noriyuki Kobayashi
Journal of Materials Science and Chemical Engineering (MSCE) , 2017, DOI: 10.4236/msce.2017.511003
Abstract: Thermochemical heat storage is a promising technology for improving thermal energy efficiency. To investigate the durability of the CaO/Ca(OH)2 reaction and develop a reactivation method, repetitive charging/discharging operation of a packed bed reactor with a thick packed bed was conducted, and variations in the discharging behavior, final conversion, and reactant activity were investigated. Owing to the formation of a deactivated sintered reactant block, the discharging time halved and the final conversion ratio decreased by the 53rd discharging operation. To enhance durability, a reactivation method using high-pressure vapor was implemented during the 54th discharging operation. Following reactivation, the final conversion increased 15%, and the discharging time tripled when compared with the discharging operation before reactivation, confirming the success of this simple reactivation method.
Verification of Quality Requirement Method Based on the SQuaRE System Quality Model  [PDF]
Kazuhiro Esaki
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.31006
Abstract:

For a purpose of suitable system product development and acquisition successfully, it is extremely important to specify the quality requirement for target system during system design phase, and developing or selecting a most suitable product finally from among the alternative candidate products. However, the quality requirements analysis is a very difficult matter because it is non-formulaic and demands much of product customer’s technical perceptiveness. Traditionally, analysis of quality requirements of a product has been conducted through questionnaires or interviews with customers based on survey investigator’s personal experience. This kind of lack of structure and incompleteness in the traditional approach introduced missing requirements and errors in prioritizing requirements to implement in the requirement analysis of a product. On the other hand, we have been working on developing the techniques (SQuaRE) for quality requirements and evaluation for system and software product for a long time in ISO/IECJTC1/SC7WG 6. For the purpose of specify the quality requirement of system product, the method of quantitative quality requirement definitions based on ISO/IEC9126 [1] quality model that includes six characteristics is widely recognized. However, independency among each quality characteristic is not sure and the suitability of method by using these six quality characteristics for quality requirement is not certified statistically. In this paper, we propose the concept of quality requirements definition method based on the SQuaRE quality models define in ISO/IEC25030 [2,3]. Also, this paper proposes the result of verification about effectiveness of quantitative quality requirement definition approach from the view point of six quality characteristics described in ISO/IEC9126.

General Frame Work of New TQM Based on the ISO/IEC25000 Series of Standard  [PDF]
Kazuhiro Esaki
Intelligent Information Management (IIM) , 2013, DOI: 10.4236/iim.2013.54013
Abstract:

Generally, for quality improvement of an organization management, TQM (Total Quality Management) is used worldwide and recognized. However, contents of activity are various, and it is difficult for organization to define the whole scope of TQM. It is very important that the activity theme about the TQM is based on the consideration of the needs and priority from the objective requirement, which should correspond to the basic consideration of quality management. If we have selected the wrong theme, and missed understanding about importance and priority of target for TQM, it may cause a significant risk in the organization management. For example, the company which got a high evaluation about the quality of management has poor management and disgraceful affair after several years, and it is a case reaching the bankruptcy. We worked on a study for improvement of technique for quality requirement and evaluation of system for many years, and have participated in the development of international standard for supporting the quality requirements and evaluation of system in ISO/IECJTC1/SC7. The organization having a specific purpose is a kind of system. It is thought that evaluation technique of the system quality is adaptive for a quality evaluation of the organization management. Therefore, this study suggests the new framework of TQM from the view point of the general framework of management defined in ISO/IEC25040 and TQM matrix. Furthermore, this paper presents the result of comparison between proposed action theme derived from a framework of new TQM and the example of existing TQM, and reports

Prediction Models for Total Customer Satisfaction Based on the ISO/IEC9126 System Quality Model  [PDF]
Kazuhiro Esaki
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.34037
Abstract:

The profitability of the system product is decided on the sales of the product. Furthermore, a customer satisfaction for products quality and a price have a big influence on the sales of the product. It spends limited financial resources effectively to raise the profitability of the system product, and it is necessary to realize the high quality product correspond to the customer needs as much as possible. There may be close relationship between cost of a product and an expense to implement the individual inherent attribute of system product. For the purpose of improvement of the customer satisfaction for quality of system product, the method of quantitative quality requirement and evaluation based on the ISO/IEC9126 quality model that includes six quality characteristics is widely recognized. However, independency among each quality characteristic has not been sure and the suitability of method for quality requirement of system product by using these six quality characteristics could not certified statistically. In the precedent study, introduced the requirements definition method for the quality of system product based on the system quality model defined in ISO/IEC9126 and proposed the effectiveness of it statistically. This study have measured the customer satisfaction for the system quality from the viewpoint of six quality characteristics quantitatively and confirmed the effectiveness of the technique to evaluate. In this study, we have confirmed the relationship between inherent attributes of the product and quantitative result of a measured value of total customer satisfaction from the view point of six quality characteristics statistically. This study performed the trial to clarify the relations with the inherent attributes that quantitative result of a measurement of the customer satisfaction based on six quality characteristics by the quality model of ISO/IEC9126. In addition, this study performed the development of the prediction model to estimate the total customer satisfaction for the system product from the view point of inherent attribute of the product. In this paper, we propose the effectiveness of application of the estimated prediction model and possibility of improvement of the total customer satisfaction of a system product.

Analysis of Influence of Price to Customer Satisfaction Based on the Prediction Models  [PDF]
Kazuhiro Esaki
Intelligent Information Management (IIM) , 2013, DOI: 10.4236/iim.2013.53010
Abstract:

For the purpose of improvement of the sales, confirming the influence of price to the sales and customer satisfaction of the product is important. The most suitable price should be determined from the view point of customers, and it is extremely important to implement a high quality product corresponding to the real need of customers. It may have close relationship between cost and an expense to implement the individual inherent attribute of system product. Also, it may have close relationship between production cost and price of product. For the purpose of improvement of the customer satisfaction for quality of system product, the method of quantitative quality requirement and evaluation based on the ISO/IEC9126 quality model that includes six quality characteristics is widely recognized. In the precedent study, I have introduced the requirements definition method for the quality of system product based on the system quality model defined in ISO/IEC9126 and proposed the effectiveness of it statistically. In the previous study, I have also confirmed the relationship between inherent attributes of the product and quantitative result of the measured value of total customer satisfaction from the view point of six quality characteristics statistically. I performed the development of the prediction model to estimate the total customer satisfaction for the system product from the view point of inherent attribute of the

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