Solar radiation in the Brazilian Northeast

The significant increase in recent years of the number of rural electrification systems (some thousands of them do exist) using photovoltaic technology installed in the Northeast of Brazil (1,500,000 km², approximately 42 million people) used for illumination or water pumping, calls for an improvement on the design procedures in order to reduce the burden of capital costs per unit of generated power. Such objective can be accomplished as long as a better knowledge about the solar resource is achieved, considering how much these applications depend on it.The sources of information on solar radiation in Brazil are quite varied at both institutional and publication level. At institutional level, among others, we can find the National Institute of Meteorology (INMET), State Departments of Agriculture, research institutes, universities and electric power generation and distribution utilities. Progress reports or scientific and technical journals are the main publishing vehicles where this information can be found. This way, data quality varies considerably, showing spatial and temporal discontinuities, in addition to the fact that measurement instruments and physical units of registered data are not standardized. The Solarimetric Atlas of Brazil was recently published [Brazilian Solarimetric Atlas, Final Technical Report I–IV (1997); Renewable Energy 18 (1998) 393] contains that information, which is grouped, evaluated, qualified, and presented in a standardized way. It is one of the best currently existing sources of information, and it certainly consists of almost the entirety of the existing information on the solar resource (data on solar radiation and sunshine hours) in Brazil.By using this database, simultaneous records of solar radiation (measured with pyranographs or pyranometers) and sunshine hours with heliographs were obtained in 35 different places in the Northeast region. Coefficients a and b were calculated for those different places using Angstrom's correlation. Using the geostatistical interpolation method known as ‘kriging’, the values of a and b were placed on contour maps, the coverage of which is the Northeast region. The relevant kriging estimate error maps were also obtained.The general objective of this paper is to improve the amount of the currently existing information on the solar radiation in the Northeast of Brazil. Regarding this, the contour maps of coefficients a and b have made possible estimating solar radiation in 82 additional locations, were only sunshine hours data were available.     

浅谈新疆资源优势转化中的太阳能

叙述了太阳能的特点、世界太阳能资源开发利用的前景以及新疆太阳能资源的优势,指出,开发新疆太阳能资源存在的问题,提出,开发新疆太阳能资源的对策和建议。     

湖南省太阳能资源分布特征与开发策略

分析了湖南省太阳能资源的时空分布特征,结合湖南省能源产业和经济社会发展实际,提出湖南省的太阳能资源开发利用应重点考虑热利用和风光互补发电。     

Solar energy scenarios in Brazil,Part one: Resource assessment

The “Solar and Wind Energy Resource Assessment” (SWERA) project was an international project financed by GEF/UNEP, which aimed at providing a consistent and accessible database to foster the insertion of renewable energies on the energy matrix of developing countries. This paper presents the solar energy resource assessment generated during the SWERA project by using the radiative transfer model BRASIL-SR fed with satellite and climate data. The solar irradiation estimates were validated by comparing with the ground data acquired in several sites spread out the Brazilian territory. Maps on 10×10 km² spatial resolution were generated for global, diffuse and direct normal solar irradiation. Solar irradiation on a plane tilted by an angle equal to the local latitude was also generated at the same spatial resolution. Besides the solar resource maps, the annual and seasonal variability of solar energy resource was evaluated and discussed. By analyzing the Brazilian solar resource and variability maps, the great potential available for solar energy applications in Brazil is apparent, even in the semi-temperate climate in the southern region where the annual mean of solar irradiation is comparable to that estimated for the equatorial Amazonian region.     

Resource Indicators Used for Solar Photovoltaic Plants in Uzbekistan Part 1

The annual supply of total solar irradiation (SI) to the surface of a randomly oriented photovoltaic panel (PVP) is considered; on this basis, the optimal horizontal tilt for seasonal or annual use is found. A flow diagram is proposed for determining the global total irradiation (GTI) on the surface of PVPs installed in variously oriented positions. Surkhandarya region is considered as an example. The actinometric findings obtained from the Sherabad station, as well as the PVP test results, are provided.     

一种光伏发电的太阳能资源日变化分析方法

太阳能资源评估是太阳能资源开发利用的基础,针对我国现行的太阳能资源评估标准以长期观测数据为稳定性分析对象,无法满足电力行业对太阳能资源变化特性的实际要求,提出一种太阳能资源日变化分析方法,并以北京地区为例,首先研究了不同时间尺度太阳能资源变化特征,再结合光伏电站接入电网的相关规定,利用太阳辐射日变化分析参数K′分析了晴天、多云、阴雨等典型天气条件和连续30d的太阳能总辐射日变化情况。结果表明,太阳能资源日变化分析方法能够反映1d中太阳能资源的稳定程度,对光伏发电的规划和设计具有一定的参考意义。     

Assessment of the method used to construct clearness index maps for the new European Solar Radiation Atlas (ESRA)

We present an assessment of the methods used to construct maps for a new solar radiation atlas for Europe. For this atlas, station data and satellite-derived data are used in an interpolation/merging process to derive maps of the long-term monthly global radiation that cover an area ranging from 30° W to 70° E and from 25° to 75° N. Our focus is on the discussion of the accuracy of the method applied: a co-kriging technique. Special emphasis is put on a discussion as to whether the use of satellite-derived radiation maps with a low spatial resolution brings benefits.     

On the clear sky model of the ESRA — European Solar Radiation Atlas — with respect to the heliosat method

This paper presents a clear-sky model, which has been developed in the framework of the new digital European Solar Radiation Atlas (ESRA). This ESRA model is described and analysed with the main objective of being used to estimate solar radiation at ground level from satellite images with the Heliosat method. Therefore it is compared to clear-sky models that have already been used in the Heliosat method. The diffuse clear-sky irradiation estimated by this ESRA model and by other models has been also checked against ground measurements, for different ranges of the Linke turbidity factor and solar elevation. The results show that the ESRA model is the best one with respect to robustness and accuracy. The r.m.s. error in the estimation of the hourly diffuse irradiation ranges from 11 Wh m⁻² to 35 Wh m⁻² for diffuse irradiation up to 250 Wh m⁻². The good results obtained with such a model are due to the fact that it takes into account the Linke turbidity factor and the elevation of the site, two factors that influence the incoming solar radiation. In return, it implies the knowledge of these factors at each pixel of the satellite image for the application of the Heliosat method.     

Solar Chimneys

The design and construction of the solar chimney pilot plant in Manzanares, and the investigations described below, were commissioned by the Minister of Research and Technology of the Federal Republic of Germany. The work was supervised by the energy research project management department of Kernforschungsanlage Jülich GmbH (The Jülich Nuclear Research Establishment).

The present paper communicates preliminary test results from the solar chimney pilot plant described in (1). This, the first solar chimney power plant in the world, was commissioned on 7 June 1982 and has been in continuous operation since then. Individual energy balances, collector efficiency values, pressure losses due to friction and losses in the turbine section are discussed with reference to 24-hour records. The findings agree well with results obtained hitherto in model calculations.     

Solar possibilities

A major energy transition of some kind is inevitable. For rich lands and poor alike, the energy patterns of the past are not prologue to the future. The oil-based societies of the industrial world cannot be sustained and cannot be replicated. The huge increases in oil prices since 1973 virtually guarantee that the Third World will never derive most of its energy from petroleum. Gross world oil production is likely to peak within the next decade; per capita world oil production may have already peaked. The world thus faces an awesome discontinuity in the production and use of energy.In the past, such energy transformations invariably produced far-reaching social change. The 18th-century substitution of coal for wood and wind in Europe, for example, accelerated and refashioned the industrial revolution. Later, the shift to petroleum altered the nature of travel, shrinking the planet and reshaping its cities. The coming energy transition can be counted upon to fundamentally alter tomorrow's world. This will be as true of a solar era as of a nuclear age.Sunlight is abundant, dependable, and free. With some minor fluctuations, the sun has been bestowing its bounty on the earth for more than four billion years, and it is expected to continue to do so for several billion more.     

阳光帆船

扬起帆的船，在风的推动下，可以在浩瀚的海洋里航行；是否能有一种“阳光帆船”，利用太阳光的推动，也可以在宇宙间航行呢？日本太空科学研究所的科学家回答：可以。原来，光除了具备波性质，也拥有粒子性质，光的粒子(光子)碰撞到阳