TiO2与Cu2O光催化降解对硝基苯酚比较研究

分别采用自制的纳米TiO2和Cu2O研究对硝基苯酚的光催化降解.结果表明,模拟阳光条件下,100mg·l-1对硝基苯酚水溶液的氧化亚铜催化反应半衰期为20.0min,而二氧化钛不具备可见光催化能力;在SGY-1多功能光化学反应器中,TiO2催化降解对硝基苯酚的半衰期是48.1min.产物分析表明,n-型半导体二氧化钛的光催化反应存在两种降解历程,生成二羟基硝基苯或脱除硝基.而p-型半导体氧化亚铜催化的光降解反应未检出脱硝基产物,仅检出1,2-二羟基-4-硝基苯.     

Development of new monthly global and diffuse solar irradiation estimation methodologies and comparisons

In assessing and deciding the prediction schemes of solar irradiation countrywide, better the accuracy means better the management of energy transition toward renewables. Consequently, the present study is on the development of new models to make the most accurate possible estimations of the global and diffuse solar irradiation based on ground measurements. Such analysis produces the most accurate estimations for the input of solar energy systems. This is utmost significant for deciding the investments on solar energy systems and their design periods. Turkey is a high-potent country whose solar energy market has been growing rapidly. She doesn’t have adequate reliable measurement network and there is no estimation methodology developed for each and every point within its territory. Moreover, installing such a measurement system network doesn’t seem to be economically feasible and technically possible, inter alia. Accordingly, this study defines a methodology to make the most accurate estimations of monthly mean daily solar irradiation on horizontal surface and its diffuse and beam components. For the global and diffuse estimations, new methodologies in linear and quadratic forms are developed, compared, and discussed. The comparison is applied by using mean bias error and root mean square error statistical comparison methods. The measured data values used for modeling and comparisons are provided from the State Meteorological Service of Turkey responsible authority for solar irradiation measurements. The results revealed that the methodologies explained in this study give very high accurate values of total solar irradiation on a horizontal surface and its diffuse component.     

Are policy incentives for solar power effective? Evidence from residential installations in the Northeast

State incentives for solar power have grown significantly in the past several years. This paper examines the effectiveness of policy incentives to increase residential solar photovoltaic (PV) capacity. We use county-level panel data and control for demographic characteristics, solar resources, and pro-environmental preferences. Results show that among financial incentives, rebates have the most impact with an additional $1 per watt rebate increasing annual PV capacity additions by close to 50%. Factors that affect financial returns to solar PV such as electricity price and solar insolation are also found to be significant. Results also point to a significant positive relationship between hybrid vehicle sales and residential PV capacity growth, indicating the importance of pro-environmental preferences as a predictor of solar PV demand. Back of the envelope calculations suggest that the cost of carbon mitigation through rebates is around $184 per ton of CO₂.     

Modeling the current-voltage characteristics of thin-film silicon solar cells based on photo-induced electron transfer processes

Power conversion efficiency of p-i-n type microcrystalline silicon (c-Si:H) solar cells has been analyzed in terms of sequential processes of photo-induced electron transfer. The effect of the excitonic state on the charged carrier generation has been studied compared to a conventional scheme in which only charged carriers are taken into account for the operation of the solar cells. A numerical model has been developed to calculate current-voltage characteristics of solar cells on the basis of two types of charged carrier generation processes (exciton process and charged carrier process). The light trapping effect due to a textured back surface reflector (BSR) was embedded in the numerical model by using the effective medium theory in combination with the matrix method in the field of the electromagnetic theory of light. As an application of this modeling, it was found that the reported data of the power conversion efficiency were not explained by the conventional charged carrier process model and that the combined model of the charged carrier process with the exciton process well explains the performance of the p-i-n type c-Si:H solar cells. In this way, the typical power conversion efficiencies were estimated to be 10.5% for the device (i-layer thickness: 1.8 m) with the BSR (period: 600 nm; height: 250 nm) and 8.6% for the device with the flat reflector under the condition that the fractions of the exciton process and charged carrier process were 60% and 40%, respectively.     

Modeling the current-voltage characteristics of thin-film silicon solar cells based on photo-induced electron transfer processes

Power conversion efficiency of p-i-n type macrocrystalline silicon (µc-Si:H) solar cells has been analyzed in terms of sequential processes of photo-induced electron transfer. The effect of the excitonic state on the charged carrier generation has been studied compared to a conventional scheme in which only charged carriers are taken into account for the operation of the solar cells. A numerical model has been developed to calculate current-voltage characteristics of solar cells on the basis of two types of charged carrier generation processes (exciton process and charged carrier process). The light trapping effect due to a textured back surface reflector (BSR) was embedded in the numerical model by using the effective medium theory in combination with the matrix method in the field of the electromagnetic theory of light. As an application of this modeling, it was found that the reported data of the power conversion efficiency were not explained by the conventional charged carrier process model and that the combined model of the charged carrier process with the exciton process well explains the performance of the p-i-n type μc-Si:H solar cells. In this way, the typical power conversion efficiencies were estimated to be 10.5% for the device (i-layer thickness: 1.8 μm) with the BSR (period: 600 nm; height: 250 nm) and 8.6% for the device with the flat reflector under the condition that the fractions of the exciton process and charged carrier process were 60% and 40%, respectively.     

Comparison Between Heat Pipe and Direct Heat Exchange Solar Louvre Collectors

International concern about the environmental implications of climate change coupled with increasing demand for energy to fuel modern society has lead to growing interest in using renewable energy sources as alternatives to conventional sources. The work presented in this paper compares two types of solar collector integrated into louvred shading devices. In addition to protecting glazed spaces in buildings from excessive solar gain, the collector would provide the flexibility to produce systems customized for collecting heat over a temperature-range appropriate to particular building services applications at various climates/locations. This would allow considerable savings to be made in primary energy consumption and lead to a reduction in global warming impact. Two solar absorbers, based on different techniques of heat exchange, were tested experimentally. The first was based on a direct heat exchange technique, and the second used heat pipe technology. Various comparisons were made and it was concluded that the heat pipe solar louvre collector was the preferred device.     

我国太阳总辐射气候学计算方法研究

目前太阳辐射主要通过计算获得,因此建立太阳辐射的气候学计算方法十分必要。论文利用中国54个站1961—2000年的逐日太阳总辐射和日照百分率资料,分别以天文辐射、晴天太阳辐射和理想大气太阳辐射作为三种起始值建立了各站的太阳辐射回归方程,并对其经验系数进行聚类分析,分为东部和西部两个地区。然后利用54个站1961—1990年的资料建立了3种起始值情况下,东部、西部地区和全国统一的太阳总辐射计算公式。最后利用这些站1991—2000年的观测资料对所建立的公式进行了检验。结果表明:无论是利用分区还是全国统一公式都是以天文辐射为起始值时计算结果好,其中分区公式比全国统一公式的计算结果精度略高,但差别不大。全国54个站以天文辐射为起始值的分区公式相对误差变化于2.67%~19.30%,平均为7.79%。全国统一公式的相对误差变化于3.33%~18.75%,平均为8.39%。从模拟结果的地区差异看,无论采用何种起始值,都是西部地区模拟误差小于东部地区,这与西部地区干燥、空气湿度小有密切关系。与其他研究结果相比,论文所建立的各种公式模拟结果较好,这是由于采用的资料序列长、站点多。考虑到计算天文辐射所需参数容易获得,因此建议实际应用时,采用以天文辐射为起始值的全国统一公式。     

太阳能技术在住宅建筑中的应用

太阳能技术的应用对我国住宅产业的发展具有重要意义。文章分析了目前国际和国内住宅建设领域中太阳能技术的应用形式与局限,指出了我国实现太阳能住宅建筑一体化进程中应着重解决的主要问题。     

太阳能在农村生活污水处理中的应用

结合农村生活污水处理的现状及处理过程中可能出现的问题,将太阳能技术与传统土地渗滤工艺相结合应用于农村生活污水治理工程,保证水质达到排放标准并能延长工程的使用年限。此外文章还介绍了利用太阳能应用的工艺流程、创新点与应用优势及应用前景。     

Viability of solar photovoltaics as an electricity generation source for Jordan

Viability of solar photovoltaics as an electricity generation source for Jordan was assessed utilising a proposed 5 MW grid‐connected solar photovoltaic power plant. Long‐term (1994–2003) monthly average daily global solar radiation and sunshine duration data for 24 locations – distributed all over the country – were studied and analysed to assess the distribution of radiation and sunshine duration over Jordan, and formed an input to the RetScreen Software for evaluation and analysis of the proposed plant's electricity production and economic feasibility. It was found that depending on the geographical location, the global solar radiation on horizontal surface varied between 1.51 and 2.46 MWh/m²/year with an overall mean value of 2.01 MWh/m²/year for Jordan. The sunshine duration was found to vary, according to the location, between 8.47 and 9.68 hours/day, with a mean value of 9.07 hours/day and about 3311 sunshine hours annually for Jordan. The annual electricity production of the proposed plant varied depending on the location between 6.886 and 11.919 GWh/year, with a mean value of 9.46 GWh/year. The specific yield varied between 340.9 and 196.9 kWh/m², while the mean value was 270.59 kWh/m². Analysis of the annual electricity production of the plant, the specific yield, besides the economic indicators, i.e. internal rate of return, simple payback period, years to positive cash flow, net present value, annual life cycle saving, benefit/cost ratio, and cost of energy – for all sites – showed that Tafila and Karak are the most suitable sites for the solar photovoltaic power plant's development and Wadi Yabis is the worst. The results also showed that an average of 7414.9 tons of greenhouse gases can be avoided annually utilising the proposed plant for electricity generation at any part of Jordan.