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Li F.,Shanghai University of Electric Power | Ma N.,Shanghai University of Electric Power | Zhao J.,Shanghai University of Electric Power | Qu K.,Shanghai University of Electric Power | And 2 more authors.
9th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2015-ECCE Asia | Year: 2015

Four models are used to estimate the hourly solar radiation on 15 pieces of different tilted photovoltaic (PV) modules in Wuhan, China based on power and solar radiation data during a whole year. The optimum tilt angle (OTA) in Wuhan for yearly and semi-yearly adjustment was determined. Then it was determined that the best mode is the tilt angle of PV module adjusted every half a year. In semi-yearly adjustment, OTA in semi-year of winter and summer is found as 45°, 15°, respectively. Experimental results verify the theoretical calculated values of the OTA with high precision. Energy radio (ER) reveals PV modules with adjustment of tilt angle twice a year has a capability to improve nearly 7% in comparison with fixed type. The best model was chosen based on test results from statistical indicators. The statistical results demonstrate that among the studied models, Liu&Jordan model is the most accurate. © 2015 Korean Institute of Power Electronics. Source

Han B.,Chinese Research Academy of Environmental Sciences | Liu Y.,Nankai University | You Y.,CAS Research Center for Eco Environmental Sciences | Xu J.,Chinese Research Academy of Environmental Sciences | And 7 more authors.
Environmental Science and Pollution Research | Year: 2016

Assessment of the health risks resulting from exposure to ambient polycyclic aromatic hydrocarbons (PAHs) is limited by the lack of environmental exposure data among different subpopulations. To assess the exposure cancer risk of particulate carcinogenic polycyclic aromatic hydrocarbon pollution for the elderly, this study conducted a personal exposure measurement campaign for particulate PAHs in a community of Tianjin, a city in northern China. Personal exposure samples were collected from the elderly in non-heating (August–September, 2009) and heating periods (November–December, 2009), and 12 PAHs individuals were analyzed for risk estimation. Questionnaire and time-activity log were also recorded for each person. The probabilistic risk assessment model was integrated with Toxic Equivalent Factors (TEFs). Considering that the estimation of the applied dose for a given air pollutant is dependent on the inhalation rate, the inhalation rate from both EPA exposure factor book was applied to calculate the carcinogenic risk in this study. Monte Carlo simulation was used as a probabilistic risk assessment model, and risk simulation results indicated that the inhalation-ILCR values for both male and female subjects followed a lognormal distribution with a mean of 4.81 × 10−6 and 4.57 × 10−6, respectively. Furthermore, the 95 % probability lung cancer risks were greater than the USEPA acceptable level of 10−6 for both men and women through the inhalation route, revealing that exposure to PAHs posed an unacceptable potential cancer risk for the elderly in this study. As a result, some measures should be taken to reduce PAHs pollution and the exposure level to decrease the cancer risk for the general population, especially for the elderly. © 2016 Springer-Verlag Berlin Heidelberg Source

Han B.,Chinese Research Academy of Environmental Sciences | Bai Z.,Chinese Research Academy of Environmental Sciences | Liu Y.,Nankai University | You Y.,CAS Research Center for Eco Environmental Sciences | And 7 more authors.
Indoor Air | Year: 2015

Polycyclic aromatic hydrocarbons (PAHs) are among the most toxic air pollutants in China. However, because there are unsubstantial data on indoor and outdoor particulate PAHs, efforts in assessing inhalation exposure and cancer risk to PAHs are limited in China. This study measured 12 individual PAHs in indoor and outdoor environments at 36 homes during the non-heating period and heating period in 2009. Indoor PAH concentrations were comparable with outdoor environments in the non-heating period, but were lower in the heating period. The average indoor/outdoor ratios in both sampling periods were lower than 1, while the ratios in the non-heating period were higher than those in the heating period. Correlation analysis and coefficient of divergence also verified the difference between indoor and outdoor PAHs, which could be caused by high ventilation in the non-heating period. To support this conclusion, linear and robust regressions were used to estimate the infiltration factor to compare outdoor PAHs to indoor PAHs. The calculated infiltration factors obtained by the two models were similar in the non-heating period but varied greatly in the heating period, which may have been caused by the influence of ventilation. Potential sources were distinguished using a diagnostic ratio and a mixture of coal combustion and traffic emission, which are major sources of PAHs. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. Source

Chen Z.,Hubei Provincial Meteorological Service Center | Sun P.,Hubei Provincial Meteorological Service Center | Zhang R.,Hubei Provincial Meteorological Administration Training Center
Taiyangneng Xuebao/Acta Energiae Solaris Sinica | Year: 2015

Based on the hourly total radiation observation value and simulation output of meso-scale numerical weather prediction model(WRF)for four typical months in 2011 and 2012 in Wuhan, the gradually approaching error method was adopted to improve the predicting results. Firstly, a prediction equation was built between the hourly clarity index as the dependent variable and 4 principal components concentrated from 14 factors from the output of WRF using principal component analysis method(PCA) as independent variables by conventional model output statistics(MOS) method monthly. Secondly, a new prediction equation was built between the forecast errors from above step as the new dependent variable and also newly selected predicting factors through deeply analysis. Then, the second step would be repeated to further reduce forecast error until the error was low enough. The results show that the annual mean absolute percentage error(MAPE)and relative mean square root error(MSRE)of forecasted total radiation values are 22.1% and 27.8%, respectively by CMOS and will be reduced to 17.4%(4.7% down)and 22.4%(5.4% down)correspondingly after repeating the second step only two times. The key affecting factors of the prediction errors in the first and second steps are clarity index and hour angle(different times of a day), respectively. MAPE and MSRE will be reduced by 3.8%(May)- 5.4%(August)and 4.5%(October)-6.9%(August)in two steps, respectively. The gradually approaching error method can improve the final predicting effect of the total radiation gradually. © 2015, Science Press. All right reserved. Source

Chen Z.,Hubei Provincial Meteorological Service Center | Sun P.,Hubei Provincial Meteorological Service Center | Cheng C.,Hubei Provincial Meteorological Service Center | Yan G.,Wuhan Rixin Technology Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

To achieve the optimal tilted angle (OTA) in the actual atmospheric environment and reveal the differences between it and the theoretical values, a series of comparative observational experiments were carried out with 15 pieces of different tilted photovoltaic (short for PV) modules. It is found that the daily and annual variation of the PV power generation of all modules showed a single peak. The observed OTA in winter half year (except March) is 45°, which is greater than the latitude angle, and the power generation can be increased by up to 63% compared with the horizontal module at the same period. The observed OTA in the summer half year is between 5° and 20°, which is less than the latitude angle, and the increasing rate of power generation is no more than 10% compared with that of the horizontal module. The OTAs in four seasons are 20°, 10°, 30° and 45° respectively. The annual power generation of the OTA module (30°) is 19% higher than that of 0° module. The changing trend of measured OTA is consistent with the theoretical calculation results and the measured value is greater than or equal to the calculated results (except November and December). The available energy calculated by sky anisotropic model is higher than that calculated by sky isotropic model, the difference can be up to 6.8% in winter. To increase (decrease) the inclination of PV array in winter (summer) will increase power generation significantly (to a certain degree). For adjustable PV array, there will be high power generation efficiency with OTA adjusted in March, May, September and October. The results can provide reference for applying solar energy resources to the most degree. © 2013 Chin. Soc. for Elec. Eng. Source

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