《太阳辐射能的测量与标准》评介

太阳辐射测量是研究太阳辐射的重要手段,对于太阳能利用、大气科学、航空航天技术和国民经济的许多部门都具有重要的意义。 太阳能利用是一门由众多学科互相渗透的新兴边缘学科,因此来自不同专业的太阳能工作者对有关学科的基础知识和应用情况都应有一定的了解和认识,其中当然也包括太阳辐射测量这一对太阳能利用的各个分支来说都是十分重要的内容。     

北京市太阳能气象指数介绍

北京市全年平均日照时数约为2594小时,太阳能资源丰富,适合推广太阳热水器、太阳能空调、太阳房、光伏发电技术及日光温室大棚等。北京市政府为办好绿色奥运、科技奥运,奥运会场馆周围80％至90％的路灯将利用光伏发电技术；采用太     

太阳能总辐射仿真软件的设计及其实地测量验证

依据太阳能辐射的相关理论，采用VB语言设计了基于任意地理位置的太阳能总辐射仿真软件，通过对徐州地区太阳能总辐射的实地测量研究，证实了该软件的有效性，对于指导各地区太阳能的利用具有一定的实际意义。     

太阳能总辐射仿真软件的设计及实地测量验证

文章依据太阳能辐射的相关理论，采用VB语言设计了基于任意地理位置的太阳能总辐射仿真软件，通过对徐州地区太阳能总辐射的实地测量研究，证实了该软件的有效性。     

四川地区地面太阳总辐射时空分布及气象影响因素研究

采用聚类分析法,依据152个气象站多年的月日照百分率变化规律将四川省分区,分别建立气候学计算方程得到四川地面太阳总辐射时空分布。并通过气候统计方法探讨气象因素对辐射分布特征的影响。结果表明:1)利用可反映辐射削弱状况的日照百分率将站点分类,同一区内的站点辐射状况相似,建立的计算方程更为准确,使得四川省各个地区的7个辐射观测站年总辐射的平均相对误差低至3.5%;2)川西北高原(Ⅰ区)总辐射值最大,整体在6000 MJ/m²以上,川西南山地(Ⅱ区)次之,四川高原东缘(Ⅲ区)再次之,盆地(Ⅳ区)最小,在4000 MJ/m²以下。四川总辐射整体呈由北向南、由西向东递减的趋势。3)Ⅰ、Ⅱ、Ⅲ区夏季辐射削弱最强,冬季最弱,与相对湿度、降水量、低云量、气溶胶光学厚度(AOD)的夏高冬低分布相关;Ⅳ区恰好相反,主要与低云量夏季占全年的16%,冬季占35%有关。4)由偏相关分析中的定量结果知,Ⅱ、Ⅳ区低云量均为削弱辐射的主导因素,Ⅲ区为相对湿度,Ⅰ区则相对湿度、降水、AOD三者均与辐射的削弱密切相关。     

现代测量技术在煤矿测量中的应用分析

现代测量技术在煤矿测量中的应用具有重要性与必要性。叙述并分析了全站仪、全球定位系统、三维激光技术、惯性测量系统以及遥感测量技术等现代测量技术在煤矿测量中的应用。     

国家标准《平板型太阳集热器技术条件》的修订内容及其实际意义

国家标准《平板型太阳集热器技术条件》的修订内容及其实际意义何梓年一、前言国家标准ＧＢ６４２４８６《平板型太阳集热器产品技术条件》是１９８６年５月发布、１９８７年４月实施的。十年来，该项国家标准作为全国平板型太阳集热器生产企业和经营管理部门控制产品质...     

黑龙江省太阳能利用技术现状、存在问题及发展前景

一前言黑龙江省太阳辐射资源丰富,年太阳辐射能为4.18×10~6～5.02×10~6kJ/m~2,全省年可照时数为4443～4470小时,年实照时数在2300～2900小时之间,为可照时数的55%～70%。随着黑龙江省社会经济的发展和人民生活水平的不断提高,对能源的需求量不断增长。开发和利用太阳能是必然趋势,这对于节能降耗、建设资源节约型社会具有重要的意义。     

光伏技术的发展现状

光电技术是利用半导体材料的光伏效应，将太阳辐射能转化为电能的一种发电技术，其能量来源于取之不尽、用之不竭的太阳能：光电是一种清洁、安全和可再生的能源。光伏发电过程不污染环境，不破坏生态，     

The all-sky meteorological radiation model: proposed improvements

The all-sky meteorological radiation model is a broadband solar-radiation estimation model that uses synoptic and sunshine information. The original model due to Muneer–Gul–Kambezidis was improved using regressions based on the sunshine fraction to increase the accuracy of the estimation of diffuse horizontal irradiation, thus achieving an accuracy increase for the estimation of the global horizontal irradiation. The improved model was validated using data from ten worldwide sites and using three statistical indicators:-coefficient of determination between computed and measured global irradiation data and the relevant, mean bias error and the root mean square error of the computed global irradiation. The performance of the new model was improved when compared to that of the original model. The new regression coefficients were found to be more accurate in estimating global horizontal radiation for both fine and coarse datasets.     

Estimation of solar radiation from Australian meteorological observations

A carefully prepared set of Australian radiation and meteorological data was used to develop a system for estimating hourly or instantaneous broad band direct, diffuse and global radiation from meteorological observations. For clear sky conditions relationships developed elsewhere were adapted to Australian data. For cloudy conditions the clouds were divided into two groups, high clouds and opaque (middle and low) clouds, and corrections were made to compensate for the bias due to reporting practices for almost clear and almost overcast skies. Careful consideration was given to the decrease of visible sky toward the horizon caused by the vertical extent of opaque clouds. Equations relating cloud and other meteorological observations to the direct and diffuse radiation contained four unknown quatities, functions of cloud amount and of solar elevation, which were estimated from the data. These were the proportions of incident solar radiation passed on as direct and as diffuse radiation by high clouds, and as diffuse radiation by opaque clouds, and a factor to describe the elevation dependance of the fraction of sky not obscured by opaque clouds. When the resulting relationships were used to estimate global, direct and diffuse radiation on a horizontal surface, the results were good, especially for global radiation. Some discrepancies between estimates and measurements of diffuse and direct radiation were probably due to erroneously high measurements of diffuse radiation.     

Models for obtaining solar radiation from other meteorological data

The application of solar energy requires a knowledge of long-term solar radiation and daylight data. Because of the limited availability of measured data, various formulae have been derived to compute the solar irradiance using other, more commonly available, weather data. In this article two such models are presented, MRM (meteorological radiation model) and CRM (cloud-cover radiation model). MRM requires hourly data for sunshine duration, dry- and wet-bulb temperature; while CRM requires only cloud amount. Both models can generate hour-by-hour data for horizontal global, diffuse, and beam irradiance. A brief comparison of the two models is presented. Results showed that MRM has the advantage over CRM, on account of its consistency with the measured data. Both models are now available via the Internet in the form of electronic spreadsheets.     

Determination of global radiation from satellite pictures and meteorological data

Our purpose in the future will be the forecast of the global radiation for region of Hungary and certain stations. As a first step in this study we try to determine the average daily values of the relative global radiation from values of cloud coverage using satellite pictures and from other meteorological parameter (visibility). First the relative global radiation was considered as a parabolic function of the cloud coverage. A close relationship was obtained between the amount of cloud measured in tenth and the daily average value of the relative global radiation. To correct this formula the visibility was used for calculation of the relative global radiation above the cloud amount. The value of the multiple correlation coefficient was 0.96 for Budapest, and 0.91 for region of Hungary. This fact indicates a sufficiently correct formula for calculation of the global radiation.     

A numerical solar radiation model based on standard meteorological observations

Currently, observations of solar radiation are sparse and inaccurate. At selected sites within the U.S., the accuracy should be maintained in the future. However, there are still large areas without any solar radiation observations. A numerical model based on standard meteorological data, as described above, can be used to extend the data base for design purposes. Further, the model can be used to compute the amount of direct solar flux for use with the amount of radiation on a tilted surface.The model is currently capable of computing radiation at about 300 U.S. stations and at stations for which cloud observations are available. This easily allows the generation of concurrent radiation and meteorological data for a number of stations without any previous data sets; this data generation has been done at a number of United States stations.     

Empirical correlation of estimating global solar radiation using meteorological parameters

An empirical model for the estimation of solar energy on the basis of Angstrom's model is proposed in this work. Seven regression equations are developed by using different meteorological parameters such as mean sunshine duration per hour, temperature, relative humidity, wind speed, and rainfall. The performance of the model is determined on the basis of statistical indicators like correlation coefficient(r), coefficient of determination (R²), root mean square error (RMSE), mean percentage error (MPE), and mean bias error (MBE). The results show that the equation with the highest value of r, R² and the least value of RMSE, MPE, and MBE provides better results.     

Correlation of global solar radiation with meteorological parameters over Egypt

Global solar radiation measurements on a horizontal surface (G_m), mean daily maximum temperature (T), mean daily relative humidity (RH), mean daily sea level pressure (MSL), mean daily vapor pressure (V) and hours of bright sunshine (S) are presented, analyzed, arranged in tables and graphs and discussed for five selected locations over Egypt. The locations chosen represent the different weather conditions of Egypt. Matrough and Al Arish are in the north, Cairo in the middle and Kharga and Aswan in the south of Egypt. A correlation between the measurements of global solar radiation and the meteorological parameters were given for the considered locations. The common relationship for all Egypt was also estimated. The correlation and the regression coefficients and the standard errors of estimate are listed in Table 1. The values of correlation coefficients vary from 89% to 99% and the errors of estimation are between 0.01 and 0.04.

Table 1. Geographic location of the selected stations and correlation, regression coefficients and standard errors of estimate for the model ((5), (6), (7), (8) and (9))

Full-size table (<1K)

     

On the estimation of atmospheric radiation from surface meteorological data

A large number of simple formulae for the estimation of total longwave atmospheric irradiance have been compared to both measured data and to output from the spectral model MODTRAN. MODTRAN predictions under cloudless sky agree well with the average of 38 profile-based models, and observed irradiances on the average agree with MODTRAN predictions within some 5 Wm⁻². It was also found that for “normally” stratified cloudfree atmospheres, the formulae of Berdahl and Fromberg (1982) and of Frank and Püntener (1986), both expressing the emittance as a linear function of dew point temperature, adequately reflect the radiation physics over a wide range of temperature and humidity. Besides, the formulae of Swinbank (1963) and of Czeplak and Kasten (1987), which both express the emittance as a quadratic function of dry bulb temperature, turned out to reflect the radiation physics of “normally” stratified not too dry atmospheres. For “abnormally” stratified atmospheres, a correction to empirical formulae was found. For overcast situations, the increase in atmospheric emittance beyond its cloudless value showed up to be a function of the fractional cloud cover, the cloud emittance, and the surface minus cloud base temperature difference, as phrased by Martin and Berdahl (1984). Except for a coarser spectral resolution and a slight underestimation, the simple spectral model of Berger (1988) conforms well with spectral irradiances derived from observed spectral radiances.     

Investigations of solar radiation detectors using a laboratory test facility for solar radiation meteorological instruments

A laboratory test facility for solar radiation detectors has been built and is in operation at the Aerological Station of the Swiss Meteorological Institute (SAP/SMI). This installation is conceived as a universal test bed for solar radiation exposed meteorological instruments, and consists of a commercially available solar simulator, a laser alignment system, a translation mechanism with instrument mounts, and an adjustable projection mirror. The solar simulator produces a well characterized radiation beam which can be filtered to match the terrestrial or outer space solar spectrum with an irradiance of up to one solar constant (1367 Wm⁻²). The instrument mounts and a HeNe laser beam provide a precise and easy alignment of the reference and the test instruments in the radiation beam, allowing for incident angles in the range of 15°–75°. The measurement is based on a comparison of the response of an active cavity absolute radiometer PMO6 with the signal of the test instrument.Detailed investigations of the Haenni Solar 111B type heliometer have revealed important irregularities in the sunshine threshold irradiance angular distribution. Measurements performed with and without the protection glass cover prove the exceedingly high threshold values at large declination angles to be a consequence of enhanced reflections due to the incident angle and inhomogeneities in the glass cover.Very satisfactory results have also been obtained on characterization measurements of pyranometers showing the mean values of the responsivity to be within 0.8% of the calibration values measured at the world radiation center (WRC) at Davos.