• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.437-446
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• 2009

Solar, as an ideal renewable energy, it has inexhaustible, clean and safe characteristics. In order to improve the photovoltaic system efficiency and utilize the solar energy more fully, and the DC current and DC power vary with the irradiation and module temperature, it is necessary to study the characteristics of photovoltaic I-V and P-V according to the external factors. This paper presents the analysis of characteristics of photovoltaic I-V and P-V according to the irradiation and the module temperature. The results show that the DC current and the DC power of the photovoltaic system are increased along with the increasing values of irradiation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.712-716
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• 2013

In solar generation, the PV array's azimuth is headed due south and the tilt is generally $33^{\circ}$ in order to acquire maximum generation. However, when installed in a site where there are buildings or other facilities, the azimuth and tilt are adjusted. Yet, when the azimuth and tilt are deviated from due south and $33^{\circ}$, the generation quantity is decreased substantially and currently a method to estimate the decreasing proportion is unavailable. Therefore, in this thesis, an equation on the "change ratio of solar radiation due to the changes in tilt and azimuth" was deduced by utilizing empirical data on the amount of solar radiation received according to the changes of tilt and azimuth and Interpolation. By using this equation, the decreasing proportion of generating quantity due to the installation methods of PV system can be estimated, therefore, it can be usefully utilized when designing and going through feasibility studies for development of solar generation systems.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.174-176
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• 2009

This paper aims to investigate generation conditions necessary for the most efficient generation by measuring electricity power under various irradiation conditions, since the photovoltaic generation system has high costs and low efficiency. This thesis aims to investigate generation conditions necessary for the most efficient generation by measuring electricity power under various irradiation conditions, since the photovoltaic generation system has high costs and low efficiency. Although the generation power increased with the irradiation, the former did not vary directly as the latter. This meant that the variation of the generation power was concerned in the temperature of a module, the ambient temperature, and the directions of irradiation as well as the irradiation. As for the monthly accumulated irradiation and monthly accumulated power, the maximum irradiation and generation power were observed in May and October and the irradiation, the power and the accumulated generation power were all the highest in spring, followed by fall, summer and winter.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.73-81
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• 2013

Ordinary least squares (OLS) regression is the primary statistical method in previous studies for vegetation distribution patterns in relation to landform. However, this global regression lacks the ability to uncover some local-specific relationships and spatial autocorrelation in model residuals. This study employed geographically weighted regression (GWR) to examine the spatially varying relationships between NDVI (Normalized Difference Vegetation Index) patterns and changing trends of landform (elevation, slope) and solar intensity (insolation and duration of sunshine) in Mt Geum-gang of North-Korea. Results denoted that GWR was more powerful than OLS in interpreting relationships between NDVI patterns and landform/solar intensity, since GWR was characterized by higher adjusted R2, and reduced spatial autocorrelations in model residuals. Unlike OLS regression, GWR allowed the coefficients of explanatory variables to differ by locality by giving relatively more weight to NDVI patterns which are affected by local landform and solar factors. The strength of the regression relationships in the GWR increased significantly, by showing regression coefficient of higher than 70% (0.744) in the southern ridge of the experimental area. It is anticipated that this research output will serve to increase the scientific and objective vegetation monitoring in relation to landform and solar intensity by overcoming serious constraints suffered from the past non-GWR-based approach.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.99-106
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• 2017

In this paper, an energy harvesting and profiling system is designed for smart video devices in internet of things environments without dedicated power source. The energy harvesting module provides the harvested energy from solar panel to the smart video device. The energy profiling module measures the battery outflow current and the battery voltage of the smart video device and the consumed energy of processes, and calculate the harvested energy from the energy harvesting module to the smart video device and the total energy consumption of the smart video device. The accuracy of the harvested energy measured by the device energy profiling module is validated by comparing with the calculated energy using the regional solar radiation provided by Korea Meteorological Administration. Energy harvesting data from the designed energy harvesting and profiling system can be used to design the perpetual operation of smart video devices or Internet of Things sensors.

• Journal of Energy Engineering
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• v.29 no.1
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• pp.44-51
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• 2020

The importance of ESS has been emphasized due to stabilization of power demand due to deterioration of network reliability and expansion of renewable energy sources. ESS (Energy Storage System) stores the remaining power and uses it when necessary to meet the power demand, and build the ESS system mainly in conjunction with solar and wind power. In this paper, we propose a home PV Charging Module using the Master-Slave method which is effective for low insolation. After designing the module, Fast MPPT algorithm is applied to generate the maximum output from the nonlinear output characteristics of the PV modules. The average power value for the input of PV Charging Module was 296.90 W and the output power was 289.60 W, which averaged 97.54%.

• Journal of the Korean Solar Energy Society
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• v.31 no.1
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• pp.59-67
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• 2011

This paper is focused on the effect of indoor temperature rise according to the use of windows and blinds in double skin facade in summer. For the experiment, we set up the mock-up of double skin facede and measuring temperature and solar radiation. Total 7 cases were used for measuring solar transmittance and indoor temperature rise. When the venetian blind was not installed, solar transmittance was 44.5%, and solar transmittance for the case that installed the venetian blind (angle 0) was 22.5%. Cases that opened inner and outdoor windows for ventilation showed lower indoor temperature rise than cases with closed windows. In addition, Case 5 (opened inner and outdoor windows with the venetian blind (angle 0) to reduce solar transmittance) indicated lower indoor temperature rise than Case 3(opened inner and outdoor windows). Consequently, Case 5 which uses inner and outdoor window for ventilation and venetian blind to reduce solar transmittance is the most effective way to reduce indoor temperature rise among all cases tested in this research.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.9-17
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• 2013

Hourly horizontal global solar radiation has been used as one of significant parameters in a weather file for building energy simulations, which determines the quality of building thermal performance. However, as about twenty two weather stations in Korea have actually measured the horizontal global sola radiation, the weather files collected in other stations requires solar data simulation from the other meteorological parameters. Thus, finding the reliable complicated method that can be used in various weather conditions in Korea is critically important. In this paper, three solar simulation models were selected and evaluated through the reliability test with the simulated hourly horizontal global solar radiation against the actually measured solar data to find the most suitable model for the south east area of Korea. Three selected simulation models were CRM, ZHM, and MRM. The first two models are regression type models using site-fitted coefficients which are derived from the correlation between measured solar data and local meteorological parameters from the previous years, and the last model is a mechanistic type model using the meteorological data to calculate conditions of atmospheric constituents that cause absorption and scattering of the extraterrestrial radiation on the way to the surface on the Earth. The evaluation results show that ZHM is the most reliable model in this area, yet a complicated hybrid simulation methods applying the advantages of each simulation method with the monthly-based weather data is needed.

• Journal of the Korean Solar Energy Society
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• v.39 no.3
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• pp.67-79
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• 2019

The reliable Typical Meteorological Year (TMY) data, sometimes called Test Reference Year (TRY) data, are necessary in the feasibility study of renewable energy installation as well as zero energy building. In Korea, there are available TMY data; TMY from Korea Institute of Energy Research (KIER), TRY from the Korean Solar Energy Society (KSES) and TRY from Passive House Institute Korea (PHIKO). This study aims at examining their characteristics by using Principle Component Analysis (PCA) at six ground observing stations. First step is to investigate the annual averages of meteorological elements from TMY data and their standard deviations. Then, PCA is done to find which principle components are derived from different TMY data. Temperature and solar irradiance are determined as the main principle component of TMY data produced by KIER and KSES at all stations whereas TRY data from PHIKO does not show similar result from those by KIER and KSES.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.220-220
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• 2009

In case of favourable irradiation conditions, the ratio of irradiation to the total irradiation went up and then the irradiation increased in the area with high angle of inclination. The study showed that on a clear day with the irradiation of more than $800[W/m^2]$, the pattern of alternating current power change in the fixed system was similar with that in the single-axis tracker. On the contrary, in case of unfavourable irradiation conditions, the ratio of diffuse irradiation to the total irradiation went up and then the horizontal irradiation increased. In the demo system, the fixed system, the single-axis tracker and the dual-axis tracker all had low generation power and similar generation pattern with each other. The study showed the generation power varied with the irradiation in the fixed system, while in the single-axis tracker and the dual-axis tracker, the amount of the generation power variation was much more than the irradiation variation. The demo system was operated from 11:00 AM to 2:00 PM for generating power, during which time, 46[%] to 56[%] of the total generation power was produced. In this study. the generation power was increased by 147[%] in the fixed system, by 136[%] in the single-axis tracker, and by 164[%] in the dual-axis tracker, and the pattern of generation power was similar with the generation power variation in the situation where the irradiation increased by 140[%] in the spring with plenty of insolation. The alternating current power was more sensitive to variation of the irradiation than to that of the surface temperature of a module. The variation of the irradiation had a more positive effect on the generation power than the type of array.