Amount Of Global Solar Radiation Research Articles

Estimation of the daily global solar radiation; Nepal experience

This work focuses on estimation of global solar radiation and, in particular, it explores the effect of precipitation and temperature on solar radiation profile of Kathmandu (Nepal). An accurate knowledge of solar radiation distribution in each particular geographical location is crucial for the promotion of solar energy technology. The best way of knowing the amount of global solar radiation is to install quality instruments at many locations in the given region. This requires their day to day maintenance, recording and calibration, which is very costly in developing countries like Nepal. Thus, the alternative approach is to correlate meteorological measurements with appropriate models and investigate the key parameters. For the research activities the RadEst program has been used. It includes, for evaluating the daily global solar radiation values at a given latitudes, four models which estimate the atmospheric transmissivity by measurements of daily temperature range and precipitations. The model parameters are fitted in 2years data by iterative procedures. The values obtained by these models are, then, compared with measured radiation data. The paper reports graphical and statistical evaluations suggesting that among the four models, the Modular DCBB is the best model for Kathmandu area. This result is useful for designing solar panels able to maximize the harvesting of solar energy and to reduce the chronic shortage of hydrocarbon fuel that Nepal imports in a significant amount each year.

Statistical comparison of global solar radiation estimation models over Turkey

Production of energy from clean and renewable resources is an appealing subject nowadays. Solar energy has an important place among the renewable energy resources. METEONORM, TEKNOLOGIS and GEPA are models used to estimate the amount of global solar radiation recorded over the surface of Earth particularly over the region of Turkey. In this work, we compare and evaluate these models in terms of accuracy of estimation. As a result, the TEKNOLOGIS model is found to be superior to the other models in terms of preciseness in the estimation of the amount of horizontal global solar radiation reaching at a particular point over the region of Turkey.

Comparison of Different Models for Estimation of Global Solar Radiation in Jharkhand (India) Region

In this paper with the help of different empirical models we have estimated the value of monthly average global solar irradiation for Ranchi (23.3500°N, 85.3300°E), a tropical location. The values of monthly average global solar radiation are calculated using the regression constants in the models (both linear and quadratic) suggested by: Angstrom Prescott, Rietveld, Ogleman, Akinoglu, Glover, Gopinathan and Sangeeta et al. All the regression models are investigated, validated and compared. On comparison it was observed that the quadratic models are overall more accurate for calculating the Global Solar Radiation for the Jharkhand region, but the Angstrom-Prescott model as well shows better variance for most of the months. The calculated data from these models is compared with the data provided by MNRE [1]. GSR values are important parameters for designing any Solar Power Systems as the whole solar power generation is directly proportional to the amount of global solar radiation. The calculated and measured data are simulated using MATLAB.

Increase in Global Solar Radiation with Total Cloud Amount from 33 Years Observations in Japan

In general, a change in the total cloud amount (TCA) affects the solar irradiance at the surface as a result of on-the-way reflection of solar radiation. The amount of global solar radiation (GSR) increased globally after c.a. 1990, and this increase resulted from a decreases in the TCA and an increases in atmospheric transparency. Here we present the TCA and GSR trends categorized by the TCA for 33 years in Japan (from 1974 through 2006) on the basis of simultaneous observation from 53 weather stations. These trends are calculated using data obtained on a daily basis. The results averaged across Japan show that both GSR and TCA are increasing at the rate of 2.2% and 1.5% per decade, respectively. In most of Japan (regions further north than Kyushu), a high GSR increase rate mostly appears with a large TCA. This fact cannot be accounted for by the increase in the atmospheric transparency alone. There are two possible causes for increases in GSR and TCA in Japan: a change in cloud appearance frequency against the solar zenith angle and a decrease in cloud optical thickness.

METHODS TO ESTIMATE TILTED SURFACES GLOBAL AND SPECTRAL IRRADIANCE IN BANGKOK

Since 2006, we have been measuring irradiation, spectral irradiance, and other meteorological data for Bangkok, Thailand. This report describes two research results were obtained through research using those meteorological data. The first study was intended to find a method for presuming the amount of global solar radiation of the slope, tilted south by 14°, that can be expected to yield the maximum global irradiance in metropolitan Bangkok. First, we examined six previously reported models to separate horizontal global irradiance into direct and diffusion elements. Four other models were examined to estimate irradiance on tilted surfaces by direct and diffusion elements. The surface was tilted at a 14° angle to the south. The prediction accuracy of the combination of two models was evaluated using the root mean square error (RMSE) values. Results showed the most appropriate combination of those models: a combination of U, W, and Z models with the isotropic sky irradiance model yielded the smallest RMSE value. The second investigation developed a method to estimate spectral irradiance using global irradiation values. Theoretically, distribution of the solar spectrum irradiance is determined by various factors such as airmass, atmospheric pressure, water vapor, solar altitude, turbidity of atmosphere, and the earth's albedo. For variables in this study, we used amounts of the horizontal global irradiation, airmass, rainfall, and precipitable water processed with the sigmoid function. We developed a method for estimating the amount of global irradiance on the tilted surface under optimum condition, and developed a precise estimation method for spectrum irradiance on a horizontal plane for metropolitan Bangkok.

Life cycle assessment and evaluation of energy payback time on high-concentration photovoltaic power generation system

In this study, the environmental load of photovoltaic power generation system (PV) during its life cycle and energy payback time (EPT) are evaluated by LCA scheme. Two hypothetical case studies in Toyohashi, Japan and Gobi dessert in China have been carried out to investigate the influence of installation location and PV type on environmental load and EPT. The environmental load and EPT of a high-concentration photovoltaic power generation system (hcpV) and a multi-crystalline silicon photovoltaic power generation system (mc-Si PV) are studied. The study shows for a PV of 100 MW size, the total impacts of the hcpV installed in Toyohashi is larger than that of the hcpV installed in Gobi desert by 5% without consideration of recycling stage. The EPT of the hcpV assumed to be installed in Gobi desert is shorter than EPT of the hcpV assumed to be installed in Toyohashi by 0.64 year. From these results, the superiority to install PV in Gobi desert is certificated. Comparing with hcpV and mc-Si PV, the ratio of the total impacts of mc-Si PV to that of hcpV is 0.34 without consideration of recycling stage. The EPT of hcpV is longer than EPT of mc-Si PV by 0.27 year. The amount of global solar radiation contributing to the amount of power generation of mc-Si PV is larger than the amount of direct solar radiation contributing to the amount of power generation of hcpV by about 188 kW h/(m 2 year) in Gobi desert. Consequently, it appears that using mc-Si PV in Gobi desert is the best option.

Determining optimum tilt angles of photovoltaic panels at typical north-tropical latitudes

An application of renewable energy technology is the installation of photovoltaic systems that generate power without emitting pollutants and requiring no fuel. Solar radiation varies with geographic latitude, season, and time of day due to the various sun positions in the sky. Hence, the problem of designing the optimal tilt angle and the orientation of a solar panel arises for maximizing solar radiation collection at a fixed latitude. An approach of employing sky radiance models for determining optimal tilt angle values of solar collectors with respect to a set of geographic latitudes was conducted by using a data archive of the daily global solar radiation collected by the Italian Institute of ENEA. The results provided a set of tilt angles for winter months that enables a solar panel to absorb the maximum amount of global solar radiation and another set of smaller tilt angle values for summer months, as well. The great difference between these two sets suggested to us to plan semifixed solar panels whose tilt angle can be changed twice a year. The relative gain in solar radiation collectable should not be negligible, as shown in Sec. III.

Estimation of aerosol effects on surface irradiance based on measurements and radiative transfer model simulations in northern China

Using 15 months' worth of ground‐based broadband and spectral radiation data at Xianghe, a suburban site in northern China, aerosol effects on surface irradiance are explored in this study. Collocated aerosol optical depth (AOD) and surface irradiance measurements made under cloudless sky conditions are first binned according to solar zenith angle. Empirical equations are then developed to describe the relationships between AOD and surface shortwave radiation (SWR) and photosynthetically active radiation (PAR). The equations are finally used to derive quantitative estimates of aerosol effects on surface SWR and PAR. The annual mean aerosol direct radiative forcing (ADRF) values for SWR and PAR derived from measurements are −32.8 and −16.6 W m−2, respectively, which are in good agreement with those derived from radiative transfer model simulations. Variations in aerosol concentration not only change the amount of global solar radiation reaching the Earth's surface but also alter the relative proportions of diffuse and direct solar radiation. The annual mean changes in direct and diffuse SWR induced by aerosols are −89.6 and 51.0 W m−2, respectively, and the annual mean changes in direct and diffuse PAR induced by aerosols are −51.0 and 29.6 W m−2, respectively. The effects of regional haze in China on climate and crop production should be further studied.

Geographical distribution for malignant neoplasm of the pancreas in relation to selected climatic factors in Japan

BackgroundMalignant neoplasm of the pancreas has become one of the leading causes of death from malignant neoplasm in Japan (the 5th in 2003). Although smoking is believed to be a risk factor, other risk factors remain unclear. Mortality from malignant neoplasm of the pancreas tends to be higher in northern Japan and in northern European countries. A recent study reported that standardized mortality ratios (SMRs) for malignant neoplasm of the pancreas were negatively correlated to global solar radiation level. People residing in regions with lower solar radiation and lower temperatures may be at higher risk of development of malignant neoplasm of the pancreas. Therefore, this study aimed to examine the relationship between SMRs for malignant neoplasm of the pancreas and climatic factors, such as the amount of global solar radiation and the daily maximum temperature in Japan.ResultsThe study used multiple linear regression models. Number of deaths and demographic data from 1998 to 2002 were used for the calculation of SMR. We employed mesh climatic data for Japan published in 2006 by the Japan Meteorological Agency. Regression coefficients for the amount of global solar radiation and the daily maximum temperature in males were -4.35 (p = 0.00034) and -2.81 (p < 0.0001) respectively, and those in females were -5.02 (p < 0.0001) and -1.87 (p < 0.0001) respectively. Increased amount of global solar radiation or daily maximum temperature was significantly related to the decreased SMRs for malignant neoplasm of the pancreas in both males and females.ConclusionThis study suggested that low solar radiation and low temperature might relate to the increasing risk of malignant neoplasm of the pancreas. Use of group data has a limitation in the case of evaluating environmental factors affecting health, since the impact of climatic factors on the human body varies according to individual lifestyles and occupations. Use of geographical mesh climatic data, however, proved useful as an index of risk or beneficial factors in a small study area. Further research using individual data is necessary to elucidate the relationship between climatic factors and the development of malignant neoplasm of the pancreas.

Operation Prediction of a Bioethanol Solar Reforming System Using a Neural Network

The bioethanol reforming system (FBSR) using sunlight as a heat source is a fuel production system for fuel cells with little environmental impact. However, because solar radiation and outside air temperature are unstable, it is difficult to predict operation of the system with accuracy. Therefore, an operation prediction program of the FBSR using a layered neural network (NN) with the error-correction learning method has been developed. We developed a method of analyzing the operation of a natural energy system with sufficient accuracy. The weather pattern (the amount of global solar radiation and the outside air temperature) and energy-demand pattern for the past one year are inputted into the NN. Moreover, training signals are calculated by a genetic algorithm (GA). The training signals are given to the NN, and the operation pattern of the FBSR is made to learn. Operation of the FBSR on arbitrary days can be predicted by inputting the weather pattern and the energy-demand pattern into this learning NN. In this paper, the operation prediction program of the FBSR is developed, and details of the analytic accuracy are clarified. As a result of analyzing using the developed algorithm, when ±20% or less of power load fluctuation occurred, the operation plan was analyzable in 14% or less of error span. On the other hand, in operation prediction when ±50% or less of fluctuation is added to the outside temperature and global solar radiation, there was 16% or less analysis error.

リンゴ樹冠内における相対照度，相対光合成有効光量子束および相対日射量の比較

リンゴ樹の樹冠内の光条件の測定方法について, 樹冠内の全天光に対する割合を, 照度(lx), 光合成有効光量子束(μmol・m-2・s-1)および日射量(W・m-2)の測定から求め, その違いについて検討した.照度の測定による相対照度と光合成有効光量子束の測定による相対光合成有効光量子束との間には高い正の相関が認められた.しかしながら, 両者の値は明らかに異なり, 相対光合成有効光量子束は相対照度の値に比べて6.0%高かった.このことは, 1日の積算の光合成有効光量子から求めた相対光合成有効光量子と相対照度との関係にも認められ, その差は曇天日で6.7%, 晴れの日で6.8%だった.日射計による1日の積算日射量から求めた相対日射量と相対光合成有効光量子との間にも高い正の相関が認められたが, 相対日射量の値が相対光合成有効光量子の値に比べて11%高かった.

Determination and Parameterization of Some Air Pollutants as a Function of Meteorological Parameters in Kayseri, Turkey

ABSTRACT In this paper, the statistical relations between meteorological parameters and some pollutant ground level concentrations are presented. The daily average sulfur dioxide and smoke values were measured at five stations in Kayseri over 20 months. The model adopted for analysis differed from the power-law form selected by former investigators. Wind speed, degree-day temperature, the percentage of relative humidity, the previous day's pollution concentrations, and the amount of global solar radiation were the variables of multiple regression equations that were derived to calculate pollutant concentrations. The amount of cloud cover, however, had no important effect on the pollutant concentrations. The average variances of these regression equations were found as 84 and 75% for sulfur dioxide and smoke concentrations, respectively. The calculated pollutant concentrations utilizing forecast meteorological parameters reflected that the occurrence of high pollutant concentrations can be predicted.

Remotely Sensed Estimates of Solar Radiation in the Tropics Using Infrared Satellite Imagery

A statistical method is presented for the estimation of global solar radiation at the ground surface. Daytime averaged “infrared” data taken by a geostationary meteorological satellite are applied to estimate the daily amount of global solar radiation around the tropics. In order to use the infrared equivalent blackbody temperature (IR TBB) data as an indicator of cloud amount and activity in the daytime, the satellite data on each point of a 0.1×0.1 degree grid are averaged from 06 to 18 LST in one hour intervals. Surface solar irradiance is evaluated with the averaged TBB and a calculated solar radiation at the top of the atmosphere. Results are compared with measured radiation values over the ocean and on islands in the tropics. From the results of the estimation, the correlation coefficient is 0.88 and the root mean square error is 2.41MJ/m2 for daily estimation over the ocean, and 0.79 and 2.78MJ/m2 on islands.

Measurements of radiation balance components over a water surface

Results of measurement of solar and infrared radiative fluxes in the upward and downward direction over a 20 m2 evaporimeter tank are presented. The diurnal and seasonal variations of each component of the radiation balance are discussed. A numerical relation between hourly values of net radiation and global solar radiation is obtained. It is however, found that the net radiation is greater in the afternoon than in the forenoon for a given amount of global solar radiation.