To estimate of lithium-ion battery state, a new method using Electrochemical Impedance Spectroscopy (EIS) and Machine Learning (ML) is proposed. In this method, massive impedance data obtained from the EIS is used as training data for ML model, which enables state estimation with a high accuracy. However, to create a highly accurate and versatile model, it is necessary to obtain a large amount of diverse data, which requires a lot of time. In this study, we investigated two approaches to obtain many data in a short time: the introduction of a weighted division method that generates many training data from a few numbers of data, and the development of an inexpensive impedance measurement system that can be operated in parallel. For weighted division, we estimated the temperature of lithium-ion batteries using neural network and found that the RMSE decreased from 6.88 K to 1.58 K. The measurement system was found to be able to measure impedance with accuracy close to that of a general frequency response analyzer.

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In this paper, a study was conducted to efficiently use the electricity generated in a micro/smart grid using PV power generation. For this study, experiments were conducted to compare the loading capacity of photovoltaic panels and the location of energy storage devices in micro/smart grids. As a result, the loading capacity of PV panels and the efficient installation position of energy storage devices were found, and one method of efficient utilization in a micro/smart grid using PV power generation could be grasped.

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Deep reinforcement learning (DRL) is expected to be a promising optimal control method for multienergy management systems. However, no control method has been established for operation in a real environment. In addition, conventional DRL models may cause excessive charging and discharging, which may have a significant impact on actual equipment. Therefore, it is necessary to create models that are considered the actual equipment and faithfully reproduce the constraints of the actual equipment. In this study, home energy management system (HEMS) was constructed using a storage battery control model that is considered the actual equipment based on DRL. Simulation results confirmed that an actual storage battery is appropriately controlled by the proximal policy optimization (PPO) agent to the extent that they can be charged and discharged every 10 minutes.

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In recent years, energy conservation has been required in the electric energy field to realiz e a zero carbon society, and multifaceted research on energy conservation technologies has been conducted. Effective use of electric energy is necessary for energy conserva tion, and energy management systems (EMS) are attracting attention as one of the tec hnologies to achieve this goal. In this report, we focus on air conditioning equipment, which is considered to consume a lot of energy in homes and offices, and report the results of a survey on the amount of electricity consumed by air conditioning equipm ent.

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In this paper, a bipolar AC/DC converter with a special winding structure transformer is investigated using a simulation circuit. As a result, it was confirmed that the proposed converter circuit can supply two different voltages to the load and can operate as a bipolar AC/DC converter. In the future, we plan to study the characteristics of feeding actual loads using actual equipment and the characteristics when the DC load of the converter is unbalanced.

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This paper presents a theoretical approach that calculates parameters for managing distributed energy resources (DERs), considering the balancing operation of power supply and demand in electric power grids. In the proposal, first, the power trade between retail power suppliers, including functions of electric aggregators, and consumers is formulated as a problem of social welfare maximization. As the consumers cooperated with the retail power suppliers’ requests, the consumers’ economic surplus obtained in return for power consumption changes. Based on this characteristic, the authors then define economic incentives that reward the consumers’ cooperation. With the proposal, in theory, the consumers can be more satisfied even though their power consumption is controlled by the retail power suppliers. The validity of the proposal is verified through numerical simulations and discussions on their results.

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In this study, a simple and inexpensive T-h property measurement method was proposed for measuring the temperature and specific enthalpy of a flat plate PCM by cooling and heating it under adiabatic conditions on one side and a constant heat flux from the opposite side. Experiments were conducted by choosing the temperature on the adiabatic side, which is less affected by the heat transfer surface, as the representative temperature of the PCM, and thinning the thickness of the sample installed in the equipment with low heat flux. The experimental results showed that the T-h properties could be measured under quasi-steady conditions of cooling and heating of the PCM. In addition, the PCM, which is measured as the hysteresis occurring between cooling and heating in DSC measurements, was measured using this system. The results showed that the T-h properties of cooling and heating were almost identical, except for the supercooling phenomenon, and that it is possible to measure supercooling and its cancellation phenomenon, which is difficult to observe in DSC result.

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We have been developing a local air conditioning system which supplies airflow locally to user for energy-saving. This system delivers composite jet formed by colliding jets from left and right nozzles installed on a wall to user. However, Coanda effect near the nozzle causes a collision point of both jets to shift, resulting in the jet not being delivered to the user. This research aims to enhance the energy conservation performance of local air conditioning system by evaluating the effect of nozzle aspect ratio (AR) and Reynolds number (Re) on suppression of the Coanda effect using numerical analysis to clarify the appropriate range of AR and Re. As a result, although the collision point of both jets hardly influenced by the Coanda effect in the low Re, it largely shifted to left by the Coanda effect in the high Re. From evaluation of the nozzle aspect ratio, although the collision point largely shifted to left by the Coanda effect at AR=21.4, it wasn’t influenced by the Coanda effect, and located in near the central axis even if high Re at AR=3.5.

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Silica aerogel has an extremely low thermal conductivity, and it may make a superior heat insulation. This study aims to make stable composite heat insulations by combining fine silica-aerogel particles with silica-fibers as reinforcement. Two basic composite structures are examined; one with silica-fiber dispersed composite and the other with silica-paper stacked composite. The former structure provides better heat insulation properties throughout a broad temperature range, whereas the latter structure has relatively high thermal conductivities at higher temperature. Nevertheless, the silica-paper stacked composite may provide a good adhesion with other components such as concrete cement slurry to obtain building materials with excellent heat insulation properties.

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To determine the suppliable electric power by performing a demand response operation, which replaces the heat source chilled water heat load of building with a multiple heat source system, demand response operation simulations were conducted by using an existing multiple heat source system. As a result, it was found that the heat source chilled water heat load can be replaced by adjusting the amount of flowrate of heat source pumps, and electric power could be contributed.

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In this paper, the system performance of the SSHP system installed in a real building was evaluated for heating operation period. The behavior characteristics of the system and its high performance in the winter of the first year were confirmed.

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A novel hybrid cooling architecture is proposed to reduce the power consumption requirement for cooling of data centres. Countries with lower humidity levels make use of energy efficient methods of cooling, direct or indirect evaporative cooling instead of energy-intensive-compressor-based refrigerant cycle systems. In evaporative cooling water spray droplets absorb the heat to evaporate and thus cools the process air to be sent into data centre. However, this process is more efficient in dry climates as lower humidity creates the required potential for enhanced evaporation. However, in tropical climates average humidity levels are about 70- 80 % RH throughout the year. The proposed idea aims to use low temperature waste heat (emitted by the IT systems) from data centres to dehumidify the ambient air being used in the Indirect evaporative cooler to increase the efficiency of the cooler by 25%. The moisture recovered from the air is subsequently condensed and reused for the system’s cooling tower. So, in net effect by utilizing the waste heat available in the data centre, efficiency of the indirect evaporative cooler is improved, and the total overall water consumption will be reduced. The current work describes the design of a such a hybrid architecture in a humid climate. A commercial IEC chiller is chosen for reference and the performance increase with the proposed dehumidifier is illustrated. The scope also includes discussion about the design of the novel low temperature liquid desiccant-based dehumidifier, which operates under partial vacuum to be able to be regenerated by low temperature waste heat (50- 55 deg C). Finally, the annual energy savings analysis and the expected return on investment is discussed for such a system in a tropical humid climate.

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CO2 heat pump is a promising technology for water heating. M odelling of a CO2 heat pump can contribute to developing its energy saving strategies by predicting its energy performance and quantifying the impacts of the influencing factors on its performance. Although attempts have been made to develop the models, th ere was still not an effective method to predict the energy performance of a commercial CO2 heat pump, which had a variable hot water demand and ambient environmental condition. To solve this problem, we developed a backpropagation neural network model, wh ich includes these two factors as its variables and was constructed using the data collected in an actual operation of a commercial CO2 heat pump. The model could achieve a prediction accuracy more than 96%, indicating its effectiveness to predict the ener gy performance. The ambient air temperature and hot water demand were predicted to reducing and increasing the energy consumption by a factor of 0.0 39 kWh/°C and 0.0 085 kWh/L respectively while increasing the COP by a factor of 0.056/°C and 0.003 1 /L respec tively. These quantifications can contribute to the understanding of local influencing factors of a commercial CO2 heat pump, which can serve as a basis to optimize its operation strategies.

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This research deals with about a power demand for an electric heat drying system for biomass materials that can contribute to a low carbon society as carbon neutral. Especially, a power supply and demand system using PV PC S (Photo V oltaic Power c onditioning Subsystem) for a general residence is proposed about the electric heat ventilation system that dries biomass materials of a moso bamboo of Japanese bamboos, which continues to grow inexhaustibly. This research studies the saving energy power system for reduce carbon footprint by confirming the power consumption for a new biomass electric heat dryer system and the output power from a residential PV PCS 5kW equipment

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Petroleum processing generates large quantities of waste heat (WH) and flue gases (FG) that could be potentially recovered and utilised for electricity production, cost savings, and emission reductions. Current WH/FG recovery systems utilise singular or binary systems comprising organic Rankine cycle (ORC), electric turbo-compounding (ETC), or thermoelectric generation (TEG) technologies. However, these systems are prone to various challenges ranging from low efficiency, power output, and other losses. Therefore, this paper proposes and examines an innovative integrated WH/FG recovery system based on the combined ORC/ETC/TEG configuration. The system analysis and optimisation results showed that the system could potentially recover ~7.2% of the input fuel energy along with a 7.2% reduction in CO2 emissions. Overall, the findings indicate that the proposed ETC- ORC-TEG system could be potentially employed for WH-FG recovery and future utilisation.

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In a cross-flow turbine, when the opening ratio of the guide vane is narrow, the runner chamber side channel between the nozzle walls and the guide vane becomes an expanding channel, and these cause a separation and a turbulence increasing of the flow under most conditions. As a countermeasure for this problem, we present a method to reduce the pressure drop and the loss, by bringing about separation of the flow. This method is the sucking naturally atmosphere through the slit on the wall by using the negative pressure at the constricted area of the upstream side of the expanding channel. In this report, the performances of a cross-flow turbine, in both case of atmosphere intake from slit of nozzle wall which is pressure method and from hole of runner chamber wall which is conventional method, are investigated by using CFD and experimental test. As a result, an experimental turbine sucking air from the slit on the nozzle wall increases 3.9% of the efficiency compared to that in the case of sucking air from the hole on runner chamber wall, under a guide-vane opening ratio of 30%.

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This paper describes the results of a field test of micro-hydropower generation using a lab size generator. It is hoped that the use of small-scale hydropower generation will be expanded. Currently, solar power generation accounts for a large share in renewable energy sources. In addition to solar, wave and, wind power, hydropower generation should be increased in the future in order to reduce the use of energy sources such as oil and coal which is not sustainable and is also carbon generating. To increase the output of micro-hydropower generation, it is necessary to improve the efficiency of a water wheel and the generator. When the generator is not multi-poles, the efficiency is low at low speeds. In this case, an impulse water wheel was used to achieve high speed

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Recently, flood disasters due to local heavy rain have occurred in Japan that is caused by the passage of linear rain belt. This paper focused on the flood from inland waters (inland flooding). These flooding occurs when water flows into the region with no escape area. The purpose of this study is to make clear the reason of this type of flooding by considering the influence of connecting small channels in the areas where many inland flooding have occurred many times over the past few years. In this paper, the information acquisition method in waterways and the usage of small hydropower are presented.

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This paper is presented the results of an experimental evaluation of the effect of the length of the inlet nozzle of a Darrieus turbine performance. The clogging problem, which is a practical issue in small hydropower generation, can be compacted by installing an inlet nozzle between the weir to provide an acceleration length which reduces the effect on performance deterioration the water channel is blocked. However, if the nozzle length is too long, a decrease in performance also occurs because of the possible effect of changes in the fluid flow field due to changes in the nozzle angle. So, additional investigation of this mechanism in terms of nozzle angle is needed.

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The Japanese government has increasingly promoted renewable energy since the Great East Japan Earthquake of March 11, 2011 (an event which locals colloquially refer to as “3/11”), a powerful seismic occurrence originating in the Tohoku Area that triggered an accident at Fukushima No. 1 Nuclear Plant. Small hydropower energy has garnered significant attention among various renewable energy options due to its potential for local production, consumption, and utilization as well as the abundance of potential plant sites in Japan and nonproduction of greenhouse gas emissions (e.g., CO₂). One NPO in Ohi Town, Fukui Prefecture, built a siphon-type small hydropower plant at a local check dam as part of a community revitalization initiative. Construction concluded in November 2021, and the facility began operations the following month. The NPO plans to allocate a portion of the energy sales revenue to the launch of several redevelopment programs. These programs include: (a) cleanup of the Minamigawa (South River) to enable the passage of more ayu (sweet fish) along the river, and (b) forest maintenance to aid in the contain of rainwater as an additional resource for the small hydropower plant. Furthermore, the NPO plans to organize local recreation events such as firefly watching and power plant tours. The present study utilizes several analytical methods in its analysis of the economic and social impact of the Minamigawa Small Hydropower Plant program.

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The scale of wind turbines expected to generate renewable energy is very wide, from micro wind turbines to large wind turbines, and in recent years, even super large wind turbines installed offshore. Model experiments and CFD have been conducted in research on the flow around wind turbines during power generation, but there are not many observations of actual wind turbines. In this research, flow visualization around the actual wind turbine was conducted by illuminating the snowfall, and evaluated the results using PIV processing.

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To be a part of contribution of achievement of carbon neutral in future, many offshore wind farm projects have been emerging at various places including Japan and Taiwan. Completing preassembly, installation, commissioning, operation and maintenance of windfarm require multiple dedicated design activities. This paper describes example of design activities for offshore wind project such as optimization of wind turbine, support structure design activity with foundation designer, verification of structural integrity of turbine and support structure considering site load conditions including earthquakes and typhoons, verification of safety about pre-assembly, transportation and lifting of turbine main component offshore have been stated.

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