Microgrids enable efficient use of power and heat by interchanging surplus power from distributed power sources within a region. Recently, the microgrids are emerged as a mean to reduce greenhouse gas emissions. Although there have been many studies focusing on the effect of microgrids, the large part of these studies evaluated the performances of microgrids as a whole. On the contrary, this study focuses on the characteristics of each consumer consisting microgrids, and quantitatively investigates which consumers mainly contribute to cost and CO₂ reduction in microgrids. The Shapley value is adopted as an index of contributions by each consumer, and adopted to analyze the conditions under which microgrids can be established in the real world. As a result, I found that the key consumers to form microgrids are those who supply large amounts of electricity to other consumers.

Wave energy converter using oscillating water column (OWC) is one of the widely used wave energy conversion technologies in the world. In this method, an air turbine is driven by a bi-directional airflow generated in an air chamber by the OWC motion of ocean waves. A sail wing turbine has attracted attention as a new candidate for the air turbine for bi-directional flow. In this turbine, a rotating sail rotor made of a thin and flexible material such as cloth changes its shape in response to the wind direction and operates in a bi-directional airflow. In this study, a wind tunnel experiment under steady flow conditions were conducted to investigate the effect of rotor frame thickness on turbine performance in order to clarify the performance of sail wing turbine for wave energy conversion.

Magnetostrictive vibrational power generator, which are expected to be applied to flow-induced vibration power generation, can obtain higher power generation as the frequency increases. Since low-speed galloping oscillates at a reduced velocity lower than the reduced resonance velocity, the frequency increases and is suitable for magnetostrictive vibrational power generation. However, the relationship between the fluid force generated in the vibrating object and the surrounding flow during low-speed galloping is still unclear. Therefore, we conducted a free vibration experiment using a rectangular cylinder and a plate spring in a wind tunnel, and investigated the relationship between the fluid force generated in a rectangular cylinder with a side ratio of 0.2 and the surrounding flow during low-speed galloping. Multisite simultaneous measurement using hot-wire anemometers was used to measure the circulation around a rectangular cylinder, and the relationship with the surrounding flow was investigated. As a result, it was found that the fluid force has a phase lead of about 60° with respect to the vibration displacement. In addition, it was found that the induced velocity due to circulation can be captured using hot-wire anemometers.

To improve the thermal efficiency of the air-cooled organic Rankine cycle (ORC), we evaluated its performance of ORC with an intermediate heat exchanger (IHEX) realizing the waste heat recovery of the turbine based on the verification test. The turbine efficiency on the thermodynamical output by the adiabatically expanded was 42.3%. We indicated that the ORC with the IHEX could reduce 8.01% the thermodynamic heat exhaust in the condenser than that of the conventional ORC. The thermal efficiency of the conventional ORC was 2.18% whereas the ORC with the IHEX was 2.76%. The IHEX heated the working fluid at the inlet of the evaporator with the exhausted heat of the turbine and could reduce the amount of the heat supplied to its ORC own. As results, the net thermal efficiency of the ORC with the IHEX became 26.6% higher than that of the conventional ORC.

The feasibility of the broadband noise prediction generated from a horizontal axis wind turbines based on the machine learning was examined. Based on the comparison between the broadband noise predicted using the analytical results of the blade element momentum theory and the actual measured value, we discussed the issues related to its prediction in the machine learning. In the prediction of the aerodynamic noise generated from a flat plate by the machine learning, it could predict not only the broadband noise but also the discrete frequency noise with Karman vortex shedding. The spectrum distribution by the machine learning could not predict the narrowband noise centered at 6000Hz. We indicated that the prediction of the aerodynamic noise by the machine learning overestimated the noise in the low-velocity region on the hub side.

Floating offshore wind farms require a platform-group position control to mitigate wake influences on their generating electricity and aerodynamic loads. Unlike bottom-fixed wind turbine-generator systems, floating offshore wind turbine-generator systems can move under the constraints of mooring lines. Thus, a position control method of the floating platform by manipulating the aerodynamic forces of the wind turbine is rational to improve the operating performance of downstream floating offshore wind turbine-generator systems. The present study develops a generator speed-platform position combined control using the aerodynamic manipulation. The generator speed control at low wind speeds is based on the generator torque manipulation in response to the square of the generator speed. The platform position control consists of the platform surge control using the blade pitch manipulation and the platform sway control using the nacelle yaw manipulation. Consequently, the three controls, i.e., generator speed, platform surge, and platform sway, are performed in parallel. The effectiveness of the developed control method was confirmed through an aero-elastic-hydro-control coupled nonlinear dynamic simulation of a 5-MW floating offshore wind turbine-generator system under turbulent wind fields and irregular wave height variations.

Improving the ability to manage produced water is an important issue in increasing the power output of polymer electrolyte fuel cell (PEFC). In this study, a hydrophobic microporous layer (MPL) is used in PEFC to drain produced water. We fabricated a hybrid MPL by adding hydrophilic fibers to hydrophobic MPL, and investigated the effects of the hybrid MPL on the power generation performance and cold startup characteristics. When the fibers in the hybrid MPL were shorter than the thickness of the MPL, the breakthrough pressure was lower than that of the hydrophobic MPL, and the power generation performance was lower. This is thought that if the fibers are short, the liquid water stays around the fibers and inhibits the diffusion of oxygen. On the other hand, when the fibers were longer than the thickness of the MPL, the breakthrough pressure was slightly lower than that of the hydrophobic MPL, and the power generation performance was improved. This is thought to be because the fibers penetrating the MPL act as hydrophilic pathways that drain liquid water effectively. In the cold startup test using the hybrid MPLs with short fibers, an insulation cell was used to simulate a stack by using insulation material. Although we succeeded in starting up from -3°C, there was a decrease in performance after the output power increased. This is estimated to be due to larger amount of water accumulated during the cold startup.

Reducing the amount of platinum catalysts used in a polymer electrolyte fuel cell is indispensable for the widespread use of FCV. In the previous study by the authors, the oxygen transport resistance of the cathode catalyst layer (CL) has been analyzed in detail to realize efficient oxygen supply. The oxygen transport resistance in the CL was classified into two types: diffusion resistance in the CL pores, which is proportional to the CL thickness, and resistance through the ionomer, which is related to the Pt surface area. This study tried to evaluate the effects of I/C and platinum usage on the oxygen transport resistances. First, to reduce variability in the oxygen transport resistance separation, thickness control of the GDL after assembling was conducted by introducing spacers, and it was confirmed that proper separation of oxygen transport resistance is possible. Then, it was suggested that the coating speed of CL ink in the fabrication process affects the microstructure of fabricated CL and further improvement is required.

The hydrogen market is expected to expand exponentially, and hydrogen is attracting attention as a clean energy source that does not emit CO₂. We are researching a method to produce hydrogen by reacting aluminum powder in water by stirring. Considering the application of this method to a hydrogen production plant, it is necessary to increase the production rate of hydrogen. Therefore, in this study, we experimentally investigated the effect of powder concentration in water on the hydrogen production rate. In present experiment, two kinds of powders, Al and Al-5wt%Sn alloy were used, and it was found that the amount of hydrogen increases when the powder concentration is high in the alloy powder. Also, by observing the powder surface by using SEM, we were able to predict the reaction mechanism of the Al powder and water.

Hydrogen market is expected to glow exponentially and in attracting attention as a clean energy source that does not emit CO₂. The hydrogen production method by the reaction of water and aluminum powder has been studied. In this study, experiments were conducted on waste aluminum powder discharged from the machining factory, classified into five different particle sizes. The time histories of the hydrogen production rate were measured, and the accumulated volume of hydrogen was investigated from the results. The results showed that the hydrogen production rate increases with the specific surface area of the waste aluminum powder. In addition, it was found that the larger the particle size of the waste aluminum powder causes the more collision of each powder and with the stirring blade in the reactor, resulting in the formation of the powder with high specific area.

In recent years, renewable energy-based power generation methods such as solar power generation have been attracting attention as an alternative to fossil fuel-based power generation methods such as thermal power generation to prevent global warming. In order to decarbonize the heat sector in addition to the power sector, the conversion of electricity derived from renewable energy sources into gaseous fuels such as hydrogen and methane is being considered. In this study, a solid oxide electrolytic cell was employed as a means of converting electricity into gaseous fuels. In addition, considering the simultaneous co-electrolysis and methanation inside the SOEC cell, a model that takes into account the temperature field inside the cell was developed and analyzed numerically. Since it is important to achieve a temperature distribution that is compatible with co-electrolysis and methanation, we have studied the heat transfer structure and analyzed the control of cooling air volume. Next, we plan to evaluate the actual system in the laboratory and have completed fabrication and commissioning of the system.

To optimize the operating conditions of solid oxide electrolysis cells (SOECs), it is important to understand the distributions of the physical quantities in the cell, which are difficult to measure in experiments. In this study, we numerically analyze the transport and reaction in a planar SOEC. A quasi-three-dimensional model is used to reduce the computational load. We investigate the effect of the operating conditions of the SOEC on the distribution of the local gas concentration, current density, and gas temperature inside the cell. It is found from the numerical analysis that when the endothermic and exothermic heat in the cell are balanced, the temperature distribution of the cell becomes uniform in the flow direction, which is desirable in suppressing the thermal stress in the cell.

In H₂O/CO₂ co-electrolysis using solid oxide electrolysis cell (SOEC), reaction characteristics are expected to depend on the supply gas compositions. In addition, since the reverse water gas shift (RWGS) reaction occurs using Ni in the anode as a catalyst, the composition of the supply gas and that in the reaction area are expected to be different. In this paper, electrochemical performance of an anode-supported cell is investigated in various supply gas conditions under co-electrolysis, H₂O electrolysis, and CO₂ electrolysis operations. The gas compositions after the electrolysis reactions are also analyzed. It is found that the RWGS reaction does not reach equilibrium in the conditions analyzed in this study. Also, it is found that the electrochemical properties under co-electrolysis operation are similar to those under H₂O electrolysis.

The unit commitment of the thermal power units is calculated when hydrogen is introduced to gas turbine combined cycle, GTCC, units; the capacity of power units in the discussed area consists of average capacity of existing power units in Japan. The hydrogen is supposed to introduce to the flexible GTCC units which cover the load frequency control, LFC, of the power grid. Three cases are supposed, i.e., 30vol% hydrogen to 10 units of 250MW GTCC case, 100vol% hydrogen to 250MW GTCC case, and 100vol% hydrogen to 600MW GTCC case, respectively. Relatively much decrease of CO₂ emission intensity of discussed power grid is derived in the 30% hydrogen introduced to 10 units of 250MW GTCC case when the hydrogen delivery cost is reduced. CO₂ emission intensity is much less in the 100vol% hydrogen supplied to 250MW and 600MW GTCC case; the decrease of hydrogen cost is favorable for the further decrease of the CO₂ emission intensity and operational cost of the thermal power units.

In recent years, we are facing an energy crisis, and the importance of properly managing limited energy is increasing. In cold energy supply, integrated production and supply of cold energy is performed by a system composed of high-performance equipment, and it is said that energy-saving effects can be expected compared to individual production. The refrigerators used in such cold supply systems have different part-load performance characteristics depending on the cooling water temperature. The cooling water temperature is controlled by the operation of the cooling tower, and the temperature can theoretically be lowered to the ambient wet-bulb temperature. Against this background, to minimize the power consumption of the entire system, there is a trade-off relationship between the power consumption of the refrigerator and the power consumption of the cooling tower, depending on the cooling water setpoint temperature. Therefore, it is necessary to formulate a mathematical model of the cooling tower and chiller that expresses the effect of the ambient wet-bulb temperature on the cooling water temperature in order to solve the cooling water temperature operation optimization problem. In this research, we propose a method to construct a mathematical model of a refrigerator using daily operation data.

In this situation energy transition accelerating globally, MHI’s main products GTCC and steam power are needed to correspond to Carbon neutrality. In our company, decarbonize elemental technologies of these thermal power generation are being developed in TAKASAGO and NAGASAKI area, and in the TAKASAGO hydrogen park, we are preparing equipment to demonstrate longtime reliability of elemental technologies in actual condition. The other hand, Nagasaki area is the important area of developing elemental technologies, and we called this area NAGASAI Carbon Neutral Park. In this paper, we introduce developing hydrogen generation technologies etc.

Fuel ammonia is one of the carbon free fuel and IHI focused on the ammonia value chain including the use of ammonia at the existing thermal power plant. For the introduction of ammonia combustion technology in existing coal-fired boilers, IHI are working to establish their respective technologies such as small-ratio, 20%, high-ratio (calorific value ratio 50% or more) and single (100%) ammonia combustion. Demonstration of 20% ammonia combustion will be commenced with the commercial 1000MW coal-fired power plant at the end of FY2023. Furthermore, combustion test of high-ratio and single ammonia combustion have been conducted using 12MWt combustion test facilities in Aioi. These ammonia combustion technologies can be applied not only to coal-fired boilers, but also to various industrial furnaces that currently use fossil fuels. In this paper, we introduce the technological development history of ammonia combustion technology currently developed, and mainly describe the development status of single (100%) ammonia combustion test that show the initial combustion test results.

In Central Research Institute of Electric Power Industry (CRIEPI), we are developing the basic technology for a poly-generation system with CO₂ capture utilizing various fuels such as coal, waste plastic and biomass. The system is using an O₂/CO₂/H₂O blown gasifier for producing syngas. We investigated the effect of adding plastic powder to coal on gasification performance experimentally using 3t/d coal research gasifier. The gasifier is two-stages composed of a combustor and a reductor, and entrained-bed type. We evaluated the gasification characteristics of a plastic fuel that fed into the combustor and the reductor respectively. It is found that gasification performance increased by adjusting the position of plastic injection. 3t/d coal research gasifier was added a pellet fuel feed system. Gasification tests were conducted with mixed fuels of coal and pellet fuel (RPF: Refuse derived paper and plastics densified Fuel) and it was confirmed that the gasification performance was improved when using pellet fuel as well as the plastic powder.

In Central Research Institute of Electric Power Industry (CRIEPI), we are developing the basic technology for a poly-generation system utilizing various fuels for capturing CO₂. In the system, O₂/CO₂/H₂O gasification technology is used. We are verifying the reaction characteristics of the fuel injected into the reductor and the tar generation behavior by using a "Gasification experimental facility simulating reductor of gasifier" that simulates reductor part of a two-stage entrained flow gasifier. In this study, we evaluated the tar generation behavior when gasifying coal and plastic mixed fuels. In the test conditions, part of the tar was decomposed in the gasifier when only coal was gasified. In the gasification of mixed fuel of coal and plastic, the amount of tar generated increased due to the gasification of plastic. It is assumed that decomposition of tar is promoted when the steam concentration in the gasifying agent is increased, but the amount of tar increased in the test conditions. In this study, it is considered that the amount of tar generated increased due to low temperature of the gasifier. In order to decrease the generation of tar, it is necessary to pay attention to the temperature for sufficient gasification.

Adsorption technology has attracted much attention for gas storage and heat-driven adsorption heat pumps due to its low cost and recyclability. Metal-organic frameworks with high porosity have become ideal adsorbents in recent years due to their high adsorption capacity. We simulated the adsorption of CH4 in HKUST-1 using molecular dynamics. The methane uptake was calculated from the adsorption kinetic curves and compared with experimental values. The relationship between thermodynamic properties such as the thermal conductivity of the adsorption phase based on the adsorption amount was also analyzed.

This study presents a predictive model utilizing artificial neural networks (ANNs), specifically Multilayer Perceptron (MLP) and Deep Neural Networks (DNN), to forecast the properties of activated carbon under various experimental conditions. The prediction model focuses on the Brunauer-Emmett-Teller (BET) surface area and total pore volume of the activated carbon, with the carbonization temperature, activation temperature, and activation agent as the determining factors. A dataset comprising around 100 samples was used for training the model and testing its accuracy. Results indicate that the DNN model, despite its increased complexity, exhibits superior performance over the MLP model in predicting the properties of activated carbon. The DNN model showed a Mean Absolute Percentage Error (MAPE) of 14.19% for the BET surface area prediction and 17.90% for the total pore volume prediction. The findings underscore the potential of using DNN models in optimizing activated carbon production processes and tailoring its properties for specific applications. Nonetheless, the study suggests the need for expanding the dataset and including more influential factors to further enhance the model's accuracy and reliability.

From the viewpoint of effective utilization of unused energy, heat storage technology that can recover, store, and arbitrarily dissipate industrial waste heat generated from factories and power plants has been attracting attention. In this study, we developed thermal storage microcapsules with a core of erythritol, which has a high latent heat capacity among sugar alcohols and undergoes a phase change in the range from 100℃ to 200℃, which accounts for about 70% of industrial waste heat as a heat storage slurry was prepared by dispersing the developed capsules in oil to make them fluid, and thermal characteristics were evaluated by conducting experiments that simulate actual heat storage and heat dissipation. The effects of the decrease in size of the capsules were also investigated.

In recent years, the development of energy-efficient and resource-saving products has been demanded towards achieving decarbonization. Among them, the high performance of automotive heat exchangers offers various advantages such as weight reduction, pump miniaturization, and resource conservation, with further prospects for application in electric vehicles through heat recovery. In this study, an experimental investigation of a porous heat pipe for automotive use, fabricated by sintering aluminum fibers and heat transfer tube, was conducted using a wind tunnel to enhance air-side heat transfer. Sintering the fibers and heat transfer tubes together expands the heat transfer area, and thermal resistance between them becomes low. The heat exchange was performed by passing HFE7000, a single-phase gas with a superheat of +3°C, through the test section while simultaneously cooling it with air, thereby utilizing condensation heat transfer. As a result, the porous heat pipe achieved 1.5 times higher heat transfer compared to the conventional corrugated fin. Furthermore, it was observed that the porous heat pipe exhibited a uniform temperature distribution throughout the heat exchanger, which was attributed to the high thermal conductivity of the porous structure.

The aim in this study is to predict of the separability of impurities and fatty acid methyl esters by the Hansen solubility parameter analysis(HSP). In this report, in the wet refining process of biodiesel fuel(BDF) by washing with water, the water solubility and separability of residual triglycerides due to incomplete reaction, glycerin by-product produced by the transesterification reaction, methanol used at the transesterification reaction, and plant sterols derived from raw fats and oils were predicted. In the analysis, the used cooking oil methyl ester(UCOME), the used cooking oil(UCO), the oleic methyl ester(OME) and water were used as solute in HSP. The solubility parameters of solutes and solvents were cited from literatures. It was found that methanol and glycerin are easily soluble in water. On the other hand, the triglyceride component cannot be removed by washing with water, as the result, it remains in the methyl ester component. Therefore, it is necessary to complete the reaction process before washing with water in order to increase the purity of the product.

This paper describes the fundamental study about utilization of co-glycerol (CG) derived from biodiesel fuel (BDF) production especially exhausted from small BDF plant which has no facility to dispose them by themselves. The method to add value to this CG is refining and production of pyrolysis oil under low temperature around 500 °C, using small solar thermal collector (STC) with type of parabola trough as its heat source. Compared with the previous study, this paper especially focuses on an evaluation of the quantity of CG to be treated from single collector. As a result, the maximum quantity of co-glycerol to be treated from single STC once at a time was equivalent to a half volume of test tube, which was inserted inside STC and its length was almost the same as that of STC, and this was limited due to the occurrence of bumping and flowing out without refining. However, this problem was mitigated by dynamically reducing the area of parabola-trough mirror, then reduction of rapid increase of temperature inside STC. Furthermore, the batch type systems exchanging the test tube containing CG is adequate for increasing the amount of CG to be treated by this STC.

This paper describes the fundamental study about utilization of co-glycerol derived from biodiesel fuel (BDF) production especially exhausted from small BDF plant which has no facility to dispose them by themselves. The method to add value to this co-glycerol is refining and production of pyrolysis oil under low temperature around 500 °C, using small solar thermal collector (STC) with type of parabola trough as its heat source. This paper especially focuses in the usage of oil products as blended fuel in BDF and the refinement and recovery of metal, which is the component of BDF production catalyst, from solid residue. Here, the blending ratio of oil to BDF was determined so that all of the oil produced was blended in the BDF produced at the same time, then oil blended with BDF consisting of 3 vol-% oil and 97 vol-% pure biodiesel (B97O3) was used. As a result, the fuel properties and engine performance of B97O3 were almost the same as B100, and the potassium derived from catalysts of BDF production was recovered as K₂CO₃.

This paper investigates waste heat power generation and biochar yield improvement using thermoelectric devices in a portable, small-scale pyrolysis reactor. By using a typical condition for smaller-sized pyrolysis plant, we examined. thermal balance during a 100 kg wood pyrolysis process. Thermal balance simulations of the reactor reveal that approximately 22.5% of the wood biomass input is needed for maintaining reactor temperature, significantly reducing biochar yield. Theoretical models calculated heat dissipation reductions with insulation and the power generation potential of thermoelectric devices. Results showed that installing thermoelectric devices on only half of a reactor wall could generate 0.18 kW power while keeping heat loss to approximately half of the existing process. This configuration also improves biochar yield and suggests the possibility of kWh-level power generation leveraging temperature differences with the atmosphere. Our results demonstrate the potential to improve biochar production efficiency and the feasibility of thermoelectric power generation.

Ships are required to improve their environmental performance, and fuel consumption regulations such as the EEXI regulations require the reduction of carbon dioxide emissions. These regulations require the same environmental performance from ships currently in service as from newbuildings, and conventional ships in service are reducing their maximum power output to reduce carbon dioxide emissions. Therefore, we investigated the effects of co-firing C fuel oil and synthetic fuel. Under the condition of 30[%] synthetic fuel blending, the engine speed was 265[rpm] at low speed, and the ignition time was 1[deg. In the presentation, combustion analysis will be presented along with exhaust gas characteristics.