An evaluation to determine areas with cloudiness fluctuations and the cloudiness ratio throughout January and June in Fukui is done using Himawari-8 satellite image’s available geophysical parameters data provided by JAXA P-Tree system. Geographic information system (GIS) is also considered to compare cloudiness ratio, cloudiness fluctuation and solar radiation with land use to understand areas where clouds form easily to reduce errors in photovoltaic energy (PV) forecasting. Three areas with different land use were chosen to evaluate low level cloud conditions. Evaluation results show that cloudiness fluctuations are higher in January and sudden clouds are more likely to occur in areas with high concentration of buildings in January.

We discuss the relation between the heat balance of the cell module and the snow slipping on the solar panel array installed in snowy Aomori city. The heat flow and temperature sensors installed on the backside of the panel are powerful tool for the estimation of the heat balance of the cell module. The inverse heat flow was observed just before the slipping of the snow. It strongly suggests the support from the albedo of the snow to slip the snow on the surface of the module.

For five weather observation stations in Naganuma, Tsukuba, Gifu, Tosu and Okinoerabu released by NEDO, horizontal global solar radiation HQH(IT,IJ) and spectral integrated wavelength S_HX(IT,IJ) were organized hourly. When these solar radiation amounts are arranged in descending order ignoring the year, it was found that a characteristic curve (solar radiation characteristic curve) is shown depending on the location and month. Using this, it were clear that correcting of uncertain data, relationship between the sunshine ratio and the monthly total solar radiation energy.

MONSOLA-20 which recorded the monthly mean of solar radiation and METPV-20 which recorded the hourly meteorological data were released by NEDO in 2021. In this study, we compared these data with MONSOLA-11 and METPV-11. Overall, there was a slight trend toward an increase in solar radiation due to the update of the statistical period and improved solar radiation estimation model. We found that slope solar radiation was changed in conjunction with horizontal solar radiation, and that there is a seasonal variation between horizontal solar radiation and slope solar radiation.

The daytime sky of Toyohashi was observed for one year from June 2021 to May 2022 using two all-sky cameras, a horizontal plane all-sky pyranometer, and a PV power generation facility. From the results of the observations, we created a weather database. We statistically analyzed the effect of the number of cloud layers on changes in solar radiation intensity based on the observation results, and examined how many layers of clouds should be taken into account in the solar radiation forecasting system using sky image analysis that we are developing in this laboratory.

The daytime sky at Toyohashi city was observed every five seconds from June 2021 to May 2022 by using two all-sky cameras. Based on the images, the relationship between number of clouds layer and fluctuation of solar irradiance was statistically analyzed for every hour. Here, the clearness index was calculated with the solar irradiation from the pyranometer. The fluctuation component is evaluated with Fourier analysis. The results indicate that the magnitude of fluctuations increases with the increase of the number of the cloud layer.

Western sea water temperature off at Amakusa-City is 28 C. Evaporation rate 9.127cc/m2/ minutes. Evaporation amount 52.565mm/cm2 for 96 hours. 50 km/h of western wind. The length of steamy area = 50 km/h x 96 h = 4800 km. The length of the precipitation area like a line (from Amakusa -City, Moji-- City) is 219 km. A torrential downpour concentration ratio = 21.9 times = 4800/219. Therefore calculated rainfall =52.56 mm x 21.9 time =1153 mm. The measured rainfall in Ureshino city= 1024 mm. Therefore the error is 13%. There is a possibility that a torrential downpour prediction can be expected by sea water temperature.

The power of the typhoon No.11 is 9.03E+15 watt, and the energy is equivalent to a share for 240 years of the primary energy consumed of Japan. The total precipitation of the largescale typhoon No.11 is equivalent to a share in 1.9E+12ton for three years of the annual precipitation of Japan.

Variability in the electric power supply from PV power generation systems, electric power demand and residual demand on the national scale in Japan is evaluated using simulated data for 30 years. We found the relationship between variation in the annual mean of PV power supply and that of the electric demand is positive and it causes the control of the variability in the annual mean of the residual demand.

Solar radiation data are necessary to estimate the photovoltaic power generation. To estimate solar radiation at any given location, meteorological satellite images have been used to this time. However, accurate estimations under specific weather conditions, such as slightly cloudy skies, were difficult due to computational costs and the complex effects of cloud structure on radiative transfer. In this study, a solar radiation estimation model was developed using multiband information of Himawari-8 by combining a neural network and a radiative transfer model. The validation results showed that the newly developed model improved overall estimation accuracy and was able to adequately represent the solar radiation under certain conditions.

The spongy fault zones containing a large amount of water are supposed to have been involved in the frequent occurrence of earthquakes due to global warming. After the land uplift in Japan stopped in 1985, the sea level has risen at an average rate of 2.8 mm/year, and small and medium-sized earthquakes of M5 or less have occurred frequently in proportion to the sea level. On the other hand, it was suggested that the crustal pumping motion that causes large earthquakes of M5 or more are caused by the highly pressurized water in the fault zone by the snow load, to rise up the Tohoku region after snowmelt. Therefore, we analyzed changes in land height, snow cover and sea level changes in various parts of Japan, and found that the crustal pumping movement is promoting the starting off the coast of Sanriku and moving eastward while rising onto the Pacific plate. Based on this mechanism, we improved the model for estimating the amount of crustal deformation that triggers large earthquakes, and investigated earthquake prediction methods.

This paper is described about the annual monitoring results of the real residential house equipped with OMX and power storage system, in order to demonstrate All Time Real ZEH (Zero Energy House). OMX is the solar space heating, cooling, Ventilation and hot water supply System with a Unit integrated heat pump and roof-integrated PVT Panels. As the results, the annual energy self-sufficiency rate was 104% and the annual independence rate was 56% with comfortable indoor environments throughout a year.

In recent years, global warming and the experience of power outages have focused attention on becoming self-sufficient in electricity at home. In this context, photovoltaic power generation is becoming popular, but it can provide electricity only during the daytime, so, storage batteries are necessary for electricity self-sufficiency.

Therefore, The purpose of this study is to investigate the possibility of electricity self-sufficiency in model house with photovoltaic power generation, storage batteries and electric vehicle in Fujioka city, Gunma prefecture by conducting a simulated power load experiment.

The results of the spring and winter experiments are reported in this report.

Small-scale experiments were conducted to improve the conversion efficiency of diesel generator (6 kVA) by introducing a battery energy storage system (5.5 kW - 5 kWh) to power to a load. Fuel consumption rate and various conversion efficiencies were evaluated for the load (0-5000 W) using the voltage or the state of charge (SOC) control of the lithium-ion battery for starting/stopping the generator. The results showed that significant improvement effect in low load area, for example the energy efficiency under SOC control was 344% better than that of the generator alone at a load of 300 W.

The Passive House (PH) standard certified by the Passive House Institute (PHI) in Germany is known as the world's top energy-saving and low-carbon houses, and 57 of them have already been built in Japan (as of October 2022). In this paper, the characteristics of the design specifications for these houses were analyzed using the Passive House database. As results, trends in wall, roof, and floor slab insulation were identified according to the climatic conditions. Approximately 30% of the buildings used solar thermal energy for domestic hot water supply. When the certified values for heating and cooling loads were met, the primary energy consumption tended to be much smaller than the certified values.

Changes in lifestyles due to the spread of COVID-19 have also affected energy consumption in homes. Starting in April 2025, it will become mandatory in Tokyo region to install solar power generation and storage systems in newly built houses, and this initiative is expected to expand nationwide. This paper identifies trends in power consumption and changes in the power self-sufficiency rate and independence rate during the comparison period between 2019 and 2020, targeting wooden detached houses with solar power generation and storage systems.

In resent year, the electricity generated by photovoltaics have been required to be consumed in their houses. By sharing electricity among multiple households, more electricity generation can be self-consumed. In this paper, based on the results of actual measurements in which electricity is shared among multiple homes, the effect of improving the electricity self-sufficiency rate is shown. In addition, we evaluated the effects of family composition and power consumption patterns on the power self-sufficiency rate.

This paper reports changes in lifestyle and energy consumption due to the spread of COVID-19 through questionnaire survey on lifestyle changes and analysis of energy data recorded by HEMS.

Two households are chosen from target houses of residential town in Kumagaya city, Saitama prefecture. We conducted a detailed analysis of the hourly energy consumption of the two households, and clarified changes due to differences in home hours.

In recent years, the electric energy sector has been required to improve energy efficiency in order to achieve carbon neutrality. Therefore, energy management systems (EMS) have been attracting attention as one of the energy conservation technologies. The authors have focused their research on air-conditioning equipment, which is expected to have large energy consumption in homes and offices.

In this paper, we examine the power consumption behavior of air-conditioning equipment using behavioral economic methods.

Photoelectrochemical hydrogen generation is a promising technology for converting sunlight into CO₂-free chemical energy. As one of the problems, the adhesion of hydrogen bubbles on the electrode and the window material hinders the efficient energy conversion. Hence it is important to evaluate the bubble adhesion on surfaces configuring of photoelectrochemical reactor. In this research, we developed the measurement technique of bubble adhesion and demonstrated it for some materials and varied measurement conditions. In addition, we conducted hydrogen bubble control experiment to examine the effective handling of bubble flows.

Energy harvesting is a potential technology that converts ambient energy into electricity. In this study, we investigated a metal harvesting power generation system using a borax cross-linked PVA gel. The gel fabrication process was established, and its performance was quantitatively evaluated from discharge and polarization curves. In addition, we used the metal harvesting power generation system to drive the machine with a motor, for which we fabricated a gel with a hollow-cylinder shape.

Rotating ring disk electrode methods - which have been used as an evaluation method for catalysts for polymer electrolyte fuel cells - , have poor reproducibility especially in the region of diffusion limiting current. The aim of this study is to analyze the factors such as oxygen concentration in solution and catalyst dispersion state on a disk electrode that cause the poor reproducibility. Under the condition of oxygen replacement for 30 minutes, the uncertainty of oxygen concentration accounted for 30.1% of the total uncertainty. When catalyst inks were dispersed by ultrasonic irradiation, the diffusion limit current derived from the oxygen reduction current increased with the increase of the ultrasonic irradiation time and reached a maximum at 30 minutes. On the other hand, when the catalyst ink was prepared by ultrasonic irradiation (30 s)-shaking (19 h)-ultrasonic irradiation (90 s), the maximum diffusion limiting current was obtained.

In order to improve the light utilization efficiency (LUE), which is one of the evaluation indices of semitransparent organic photovoltaics (ST-OPV), ST-OPV must improve the conversion efficiency (PCE) while maintaining high light transmittance. The objective of this study was to improve the short-circuit current of inverse-structured ST-OPVs using highly oriented polymeric materials. In this experiment, we investigated the use of phenanthroline derivatives, which have already been proven as materials for the electron injection layer in reverse-structured OLEDs, for the electron transport layer of ST-OPVs. As a result, we report our findings that PCE can be improved by applying phenanthroline derivatives to the electron transport layer of inversestructured ST-OPVs.

It is known that tandem solar cells can achieve higher conversion efficiency than single solar cells due to the broadening of the light absorption wavelength. In this study, we investigated semitransparent organic photovoltaics that can be used as the top cell of tandem organic photovoltaics. The use of ITiO for both electrodes, which has better transmittance in the long-wavelength region than ITO, which is commonly used, has improved the transmittance of light absorbed by the bottom cell while maintaining the power conversion efficiency.

Silver nanowires (Ag NWs) have high transparency, electrical conductivity, and excellent flexibility, and can be deposited by wet processes. Therefore, silver nanowires are expected to replace dry-process metal electrodes as the top electrode of semitransparent organic photovoltaics. In this study, we fabricated post processing free Ag NWs electrodes with a high aspect ratio of 2820 and obtained excellent optical and electrical properties. By using this post processing free silver nanowire electrode as the top electrode of semitransparent organic photovoltaics, good power conversion efficiency and high average visible transmittance were obtained.

Organic photovoltaics (OPV) are characterized by their light weight, flexibility, and high wavelength selectivity. Taking advantage of these characteristics of OPV, we are conducting research on the practical application of solar matching that can both generate electricity and cultivate plants. In this study, we investigated the power generation characteristics of OPV and the photosynthetic rate due to light transmitted through the active layer of OPV. The results suggest that the OPV fabricated in this study may be applicable to solar matching.

Effects of chlorobenzene volume and dripping speed in an anti-solvent method on the perovskite layer formation and energy conversion efficiencies of solar cells were investigated by a spin-coater with a semi-automated micro-pipette. A smooth perovskite film formation of CH₃NH₃PbI₃ crystal was successfully with better reproducibly when larger volume and faster dripping rates were applied during an anti-solvent method.

The B ion implantation to BaSi₂ films grown by molecular beam epitaxy was carried out to form p-type BaSi₂ films. According to Raman spectra, post-annealing at over 600 °C for 64 min removed the ion-implantation damage. The hole concentration increased up to 3.1 × 10¹⁸ cm⁻³, which is applicable value to a hole transport layer. The B-ion-implanted p-BaSi₂/n-Si heterojunction solar cells exhibited the rectifying behavior in current-voltage curves under AM1.5 illumination and the internal quantum efficiency reached a maximum of 72% at a wavelength of 900 nm. The conversion efficiency was 2.2%. These results open new routes for the formation methods of BaSi₂ solar cells.

It is important to remove sand particles deposited on PV modules installed in arid lands. We have proposed that electric field curtain (EFC) embedded in the module cover glass is effective for this purpose because EFC consume little electric power and does not use water. We assemble relatively large-size EFC cover glass by using transparent conductive PET film. We measured the I-V characteristics of a PV module having this EFC cover glass. It is shown that EFC is effective to prevent the decrease of generated power. Also, it is shown that grounded electrode placed between EFC and PV cells decrease the effect of the travelling electric field on the cover glass.

A hybrid CPV/PV module combining 3J cells and Si cell was fabricated and its power generation characteristics were evaluated based on long-term field tests. The power generation of the hybrid CPV/PV module is less affected by steep fluctuations in direct normal irradiance than conventional CPV modules due to the combined use of Si cell. Its power generation efficiency with respect to the global normal irradiance incident on the module varied from 17 to 35%, depending on the fraction of diffuse irradiance.

Silicon (Si) nanostructures can induce fruitful features such as reduction of the light reflectance and increase of the p-n junction interface for improvement of cell performance of Si/PEDOT:PSS solar cells. However, the high viscosity and the low permeability of PEDOT:PSS into the nanoscale pore morphology during cell fabrication has not led to dramatic performance improvements.

In this presentation, we discuss between the morphology of the Si nanocone structures and the conversion efficiency to improve the penetration rate of PEDOT:PSS and also decrease the optical reflectivity.

A study of the location and method of installing energy storage systems and the number of solar panels installed to effectively utilize PV systems (PVS) is reported. The results show that connecting PV panels that exceed the rated output power of the PCS can improve power generation during low sunlight hours such as morning and evening. In addition, by installing the energy storage device on the DC side rather than the PCS, it is possible to charge the surplus power generated that exceeds the rated capacity of the PCS due to overloading.

This study evaluated the economic feasibility of installing 0 - 20 kWh battery energy storage system (BESS) with 2 types of control (minimum purchase power or electric charge) for a residential load with existing 3 - 10 kW PV in Hamamatsu under rising electric charges. The results show that additional BESS installations are not yet profitable, but that profits can be obtained in the case of large-capacity PV such as 10 kW is installed and replace with a BESS of optimal capacity at the end of PCS life time. Moreover, minimum purchase power control with meter rate lighting is more economical than the other control.

Photovoltaic power smoothing effect using moving average method has been verified, but its impact on the power system has not yet been examined. In this study, the AGC30 model was used, moving averaging and variation rate limiting to were applied to Photovoltaic power, and Area Requirement, frequency deviation, and tie-line power flow deviation were compared. As a result, it is shown that the evaluated value could be significantly reduced on probably clear days. The results also showed that the implementation of Photovoltaic power smoothing control may enable power generation without applying variation rate limiting.

In this paper, it investigates that the battery is the separation factor of direct current microgrid system. It compares experimental value with a simulation value that incorporates the performance of the equipment actually used by means of the integrated value of the electric energy. From the comparison, it focuses electric discharge condition. Under the condition, it assesses and investigates separation factor of battery of direct current microgrid system. It can see the end in sight long operations of direct current microgrid system to improve Prediction accuracy of simulation by specifying and revising the separation. It can indicate optimal value of cost and battery volume and so on about each equipment of direct current microgrid system.

Using a small Peltier element, the amount of condensate was evaluated with respect to wind velocity (0.23 to 1.22 m/s) at a temperature of 20 °C and a relative humidity of about 90%. The results showed that the corrected condensate volume for specific humidity increased with increasing wind velocity, reaching a maximum value of 1.52 g/h at 0.75 m/s, and then decreased. Theoretical calculations also showed the same trend of increase and decrease as in the experiment, and the relative error tended to increase with wind speed, but reached a minimum at 7.9 % at 0.48 m/s.

We proposed a method for detecting short-circuit fault BPDs contained in PV arrays using partial shadows that move with the movement of the sun. If the partial shadow is on a module with a normal BPD, the I-V curve has a step; if the partial shadow is on a module with a short-circuit fault BPD, the I-V curve has no step. We experimented with an actual short-circuit fault BPD and found that the short-circuit fault BPD can be detected from the relationship between the location of the partial shadow on PV array and the maximum power point power or maximum power point current. The proposed method using movement of the sun can reduce the risk of workers falling and receiving electric shocks.

Most of the conventional technologies have difficulty in detecting the open fault position of the bypass circuit of the PV module. The purpose of this research is to develop the detection technology of the open fault position. Through the proposed detection technology is useful in a fine day, detection accuracy of fault position decreases by a lot of moving small clouds. In this paper, we show the technology to increase the detection accuracy by removing the disturbance caused by moving objects such as small clouds.

Last year, we reported the experimental results of commercial solar modules using the outdoor delta-PL method with natural light. In this paper, we report on our investigation of the improvement of workability through wireless operation and fault determination using an improved image processing algorithm, as part of our study of higher functionality.

It is difficult to detect degradation before a large output decline of photovoltaic by existing methods for detecting degradation, such as current-voltage and electroluminescence measurement. In this study, we evaluated the possibility of early detection of PID(Potential-Induced-Degradation by applying impedance spectroscopy. In addition, we examined the measurement conditions suitable for the detection of degradation.

We have been developing a system that automatically measures various electrical parameters of a PV string, diagnoses abnormalities, and notifies the user remotely. We report on field tests of two methods for detecting degradation of insulation performance: one is to measure insulation resistance at the nighttime, and the other is to detect leakage currents during the daytime.

In this paper, aiming at active discussion on electrical shock caused by PV module string/array, several basic measurements concerning this accident were carried out by using actual PV module string/array. As result, following information were obtained: (1) human body current might be affected by not insulation resistance measured by insulation tester but some unknown lower resistance component, (2) human body current is in proportion to the square of series number of PV module, and (3) blocking diode is ineffective for protection of electrical shock.

We measure the ground resistance for photovoltaic systems with the auxiliary potential probe which does not be placed on the same line with the earth electrode and the auxiliary current probe. The auxiliary current probe needs to be placed out of the area of PV system when the frame of the system works as earth electrodes. The shape and resistance value of the current probe determine the suitable distance between the current probe and the potential one and the suitable distance between the current probe and earth electrodes. We also try applying the hyperbolic function to the measured resistance values near the PV system to estimate the earth resistance. These procedures also works for floating PV systems.

In recent years, energy saving has progressed in the construction field, and passive design methods that make effective use of natural energy are often used. One of these methods is direct gain, which suppresses temperature changes between day and night, achieving both comfort and energy saving. In this study, we use unsteady CFD analysis to understand the heat storage characteristics and to study the effects of radiation and convection heat from the storage material when solar radiation is incident in a room with storage material on the floor. In this report, we classify the material structure of the floor into three types and compare them.

In recent years, highly airtight and insulated houses have become popular as a measure to reduce energy consumption. However, there are problems in terms of thermal environment, such as the tendency for heat to accumulate in summer.

Therefore, this paper clarifies trends in reducing outside air load and investigates the actual state of the thermal environment based on data obtained from annual measurements of detached wooden houses with natural energy ventilation systems such as earth tube and roof thermal collection.

In this study, we focused on how to utilize the heat capacity of wood in houses in semi-cold regions, and took up heat storage materials using log panels. The purpose of this study is to clarify the influence of the thermal capacity of wood placed inside a house like a nested structure on the indoor environment, and to establish a control method for the indoor thermal environment by combining the thermal capacity of wood with the nested structures.

The aim of this study is to examine the applicability of biomimicry in architecture. Biomimicry is the way to invent engineering solutions by imitating forms of nature. This paper shows literature research about biomimicry architecture and its analytical results. And numerical simulation is conducted to assess the performance of biomimicry architecture: the office buildings imitating cactus chosen as model of nature.

The air velocity in the open cooling (OC) room fluctuated slightly more slowly than in the close cooling (CC) room, suggesting that the opening of the window in the OC room created a path for exhaust air, which may have skillfully disrupted the mechanical rhythm of cool air from the air conditioner, resulting in a natural "coolness" sensation.

The air temperature during OC was 0.2 to 0.6℃ lower than that during CC, indicating that cooler air was distributed throughout the house during OC and exhaust air was encouraged more than during CC. This difference was less than 1℃ during the 30-minute measurement period when the outdoor temperature was around 26℃. However, this difference could be even larger depending on the conditions of high outdoor temperatures.