Solar- and Sky-Radiation Integrator 1

1961 ◽  
Vol 42 (5) ◽  
pp. 325-333 ◽  
Author(s):  
D. P. Brown ◽  
R. A. Harvey

An integrator, which automatically and periodically records the weighted average solar radiation from the previous period, has been developed. The instrument is used to obtain a measure of the average solar radiant energy per day. This measurement was previously obtained by manual—and often tedious—graphical analysis. Theoretical considerations involving averaging by passive networks are presented with experimental results which show the accuracy of the instrument.

1938 ◽  
Vol 34 (2) ◽  
pp. 208-208
Author(s):  
N. I. Kalitin

Biomedgiz. Leningrad branch. 1937 208 pp. Pr. 6 rubles. 50 kopecks. The content of the book is much wider than what the reader has a right to expect, judging by its title. The book concerns not only the measurement of radiant energy and touches on not only issues of interest to doctors working in resorts. The properties of solar radiation under various conditions, the influence of water vapor, ozone, dustiness of the atmosphere, the value of scattered radiation reflected from the sky and clouds, which is usually not paid enough attention, all these and many other issues are covered in detail in the book of prof. N.I. Kalitina largely on the basis of her own long-term research.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Essaied M Shuia ◽  
Bashir H Arebi ◽  
Ibrahim A abuashe

This paper presents the experimental data that was collected from small pilot solar chimney. The experimental data together with ambient conditions are used to evaluate the performance and study the behavior of the solar chimney; this data will be used for comparison with theoretical models in another paper [part II). The solar chimney prototype was designed and constructed at the Subrata Faculty of Engineering-Libya. The data were collected over several days of June 2011. The solar chimney system contains two main components; the solar collector and the solar chimney. The solar collector root‘ has a circular area of126 m3, the solar chimney is a PVC tube with internal diameter of 0.2 m and the total height of chimney is 9.3 m. The measurements include the intensity of solar radiation inside/outside the collector, temperature and velocity of air at the entrance of the chimney, temperature and speed of wind outside the collector, temperature of the ground inside collector al1d temperature measurements of air at speci?c points at different levels throughout the collector. Solar irradiance was found to affect the chimney temperature and subsequently affects chimney air velocity. The experimental results showed that temperature differences of (30 - 45°C) were recorded between the ambient temperature and that of air inside the chimney in the middle of the day, where the highest air temperature of 73.4°C was recorded at the entrance of the solar chimney. The maximum air velocity of 3.6 m/s was recorded inside the solar chimney at noon on 9 June. Wind speed outside the collector had a small effect on the speed of the air inside the chimney and tends to change slightly, hence, can neglect influence of wind speed on the performance of the system. Also the experimental results indicate that such type of system can trap a suf?cient amount of solar radiation, which elevates the air temperature to a suf?cient value able to generate enough air ?ow to operate a wind turbine to produce electricity; this means the solar chimney system for electricity production can work in the north-western part of Libya in the summer time at least.


Author(s):  
Y. K. Xiao ◽  
Z. M. Ji ◽  
C. S. Fu ◽  
W. T. Du ◽  
J. H. Yang ◽  
...  

Abstract. We projected incident surface solar radiation (SSR) over China in the middle (2040–2059) and end (2080–2099) of the 21st century in the Representative Concentration Pathway (RCP) 8.5 scenario using a multi-model ensemble derived from the weighted average of seven global climate models (GCMs). The multi-model ensemble captured the contemporary (1979–2005) spatial and temporal characteristics of SSR and reproduced the long-term temporal evolution of the mean annual SSR in China. However, it tended to overestimate values compared to observations due to the absence of aerosol effects in the simulations. The future changes in SSR showed increases over eastern and southern China, and decreases over the Tibetan Plateau (TP) and northwest China relative to the present day. At the end of the 21st century, there were SSR increases of 9–21 W m−2 over northwest, central, and south China, and decreases of 18–30 W m−2 over the TP in June–July–August (JJA). In northeast China, SSR showed seasonal variation with increases in JJA and decreases in December–January–February. The time series of annual SSR had a decreased linear trend for the TP, and a slightly increased trend for China during 2006–2099. The results of our study suggest that solar energy resources will likely decrease in the TP under future climate change scenarios.


2019 ◽  
Vol 11 (4) ◽  
pp. 1905-1915 ◽  
Author(s):  
Wenjun Tang ◽  
Kun Yang ◽  
Jun Qin ◽  
Xin Li ◽  
Xiaolei Niu

Abstract. The recent release of the International Satellite Cloud Climatology Project (ISCCP) HXG cloud products and new ERA5 reanalysis data enabled us to produce a global surface solar radiation (SSR) dataset: a 16-year (2000–2015) high-resolution (3 h, 10 km) global SSR dataset using an improved physical parameterization scheme. The main inputs were cloud optical depth from ISCCP-HXG cloud products; the water vapor, surface pressure and ozone from ERA5 reanalysis data; and albedo and aerosol from Moderate Resolution Imaging Spectroradiometer (MODIS) products. The estimated SSR data were evaluated against surface observations measured at 42 stations of the Baseline Surface Radiation Network (BSRN) and 90 radiation stations of the China Meteorological Administration (CMA). Validation against the BSRN data indicated that the mean bias error (MBE), root mean square error (RMSE) and correlation coefficient (R) for the instantaneous SSR estimates at 10 km scale were −11.5 W m−2, 113.5 W m−2 and 0.92, respectively. When the estimated instantaneous SSR data were upscaled to 90 km, its error was clearly reduced, with RMSE decreasing to 93.4 W m−2 and R increasing to 0.95. For daily SSR estimates at 90 km scale, the MBE, RMSE and R at the BSRN were −5.8 W m−2, 33.1 W m−2 and 0.95, respectively. These error metrics at the CMA radiation stations were 2.1 W m−2, 26.9 W m−2 and 0.95, respectively. Comparisons with other global satellite radiation products indicated that our SSR estimates were generally better than those of the ISCCP flux dataset (ISCCP-FD), the global energy and water cycle experiment surface radiation budget (GEWEX-SRB), and the Earth's Radiant Energy System (CERES). Our SSR dataset will contribute to the land-surface process simulations and the photovoltaic applications in the future. The dataset is available at  https://doi.org/10.11888/Meteoro.tpdc.270112 (Tang, 2019).


Author(s):  
G. P. Ong ◽  
T. F. Fwa ◽  
J. Guo

Hydroplaning on wet pavement occurs when a vehicle reaches a critical speed and causes a loss of contact between its tires and the pavement surface. This paper presents the development of a three-dimensional finite volume model that simulates the hydroplaning phenomenon. The theoretical considerations of the flow simulation model are described. The simulation results are in good agreement with the experimental results in the literature and with those obtained by the well-known hydroplaning equation of the National Aeronautics and Space Administration (NASA). The tire pressure–hydroplaning speed relationship predicted by the model is found to match well the one obtained with the NASA hydroplaning equation. Analyses of the results of the present study indicate that pavement microtexture in the 0.2- to 0.5-mm range can delay hydroplaning (i.e., raise the speed at which hydroplaning occurs). The paper also shows that the NASA hydroplaning equation provides a conservative estimate of the hydroplaning speed. The analyses in the present study indicate that when the microtexture of the pavement is considered, the hydroplaning speed predicted by the proposed model deviates from the speed predicted by the smooth surface relationship represented by the NASA hydroplaning equation. The discrepancies in hydroplaning speed are about 1% for a 0.1-mm microtexture depth and 22% for a 0.5-mm microtexture depth. The validity of the proposed model was verified by a check of the computed friction coefficient against the experimental results reported in the literature for pavement surfaces with known microtexture depths.


2012 ◽  
Vol 1 (2) ◽  
pp. 33-38 ◽  
Author(s):  
Noer Abyor Handayani ◽  
Dessy Ariyanti

Currently, 80% of conventional energy is used to fulfill general public's needs andindustries. The depletion of oil and gas reserves and rapid growth in conventional energyconsumption have continuously forced us to discover renewable energy sources, like solar, wind,biomass, and hydropower, to support economic development in the future. Solar energy travels at aspeed of 186,000 miles per second. Only a small part of the radiant energy that the sun emits intospace ever reaches the Earth, but that is more than enough to supply all our energy demand.Indonesia is a tropical country and located in the equator line, so it has an abundant potential ofsolar energy. Most of Indonesian area get enough intensity of solar radiation with the average dailyradiation around 4 kWh/m2. Basically, the solar systems use solar collectors and concentrators forcollecting, storing, and using solar radiation to be applied for the benefit of domestics, commercials,and industrials. Common applications for solar thermal energy used in industry are the SWHs, solardryers, space heating, cooling systems and water desalination.


2010 ◽  
Vol 18 (3) ◽  
pp. 188-195 ◽  
Author(s):  
Algimantas Sirvydas ◽  
Vidmantas Kučinskas ◽  
Paulius Kerpauskas ◽  
Jūratė Nadzeikienė ◽  
Albinas Kusta

Solar radiation energy is used by vegetation, which predetermines the existence of biosphere. The plant uses 1–2% of the absorbed radiant energy for photosynthesis. All the remaining share of the absorbed energy, accounting for 99–98%, converts into thermal energy in the plant leaf. At the lowest wind under natural surrounding air conditions, plant leaves change their position with respect to the Sun. An oscillating plant leaf receives a variable amount of solar radiation energy, which causes changes in the balance of plant leaf energies and a changing emission of heat in the leaf. The analysis of solar radiation energy pulsations in the plant leaf shows that when the leaf is in the edge positions of angles 10°, 20° and 30° with respect to the Sun, 1.5%; 6% and 13% less of radiation energy reach the leaf, respectively. During periodic motion, when the amplitude of leaf oscillation is no bigger than 10°, the plant surface receives up to 1.6% less of solar radiation energy within a certain period of time, and when the amplitude of oscillation reaches 30° up to 14% less of solar radiation energy reach the leaf surface. The total amount of radiant energy received during pulsations of solar radiation energy is not dependent on the frequency of oscillation in the same interval of time. Temperature pulsations occur in the leaf due to solar radiation energy pulsations when the plant leaf naturally changes its position with respect to the Sun. Santrauka Saules spinduliuotes energija būtina augalijai, kuri lemia biosferos egzistavima. Augalas 1–2 % absorbuotos spinduliuotes energijos sunaudoja fotosintezei, o 99–98 % absorbuotos energijos augalo lape virsta šilumine energija. Natūraliomis aplinkos salygomis esant mažiausiam vejui augalo lapu padetis Saules atžvilgiu keičiasi. Taigi augalo svyruojančio lapo gaunamas Saules spinduliuotes energijos kiekis yra kintamas, tai sukelia pokyčius augalo lapo energiju balanse ir kintama šilumos išsiskyrima lape. Analizuojant Saules spinduliuotes energijos pulsacijas augalo lape, nustatyta, kad, lapui esant kraštinese 10°, 20° ir 30° kampu padetyse Saules atžvilgiu, i ji atitinkamai patenka 1,5 %; 6 % ir 13 % mažiau spinduliuotes energijos. Augalo lapui periodiškai svyruojant, kai svyravimo amplitude yra iki 10°, per tam tikra laika i lapo paviršiu patenka iki 1,6 % mažiau Saules spinduliuotes energijos, o kai svyravimo amplitu‐de siekia iki 30°, – iki 14 % mažiau. Saules spinduliuotes energijos pulsaciju metu gautas bendras spinduliuotes energijos kiekis nepriklauso nuo to paties laiko intervalo svyravimo dažnio. Del Saules spinduliuotes energijos pulsaciju, natūraliai keičiantis augalo lapo padečiai Saules atžvilgiu, lape kyla temperatūros pulsacijos. Резюме Растения потребляют солнечную лучевую энергию, которая является основой существования биосферы. 1–2% абсорбированной лучевой энергии они используют на фотосинтез. В натуральных условиях при малейшем дуновении ветра листья растений меняют свое положение относительно Солнца. Колеблющийся лист получает переменное количество лучевой энергии, которое вызывает изменения в энергетическом балансе листа растения, что сказывается на переменном выделении тепла в листе. Анализируя пульсации солнечной лучевой энергии в листе растения, установлено, что при крайних положениях листа относительно Солнца на 10, 20 и 30 градусов на лист попадает соответственно на 1,5%, 6% и 13% меньше лучевой энергии. При периодическом колебании листа, когда амплитуда его колебания составляет 10 градусов, за известный промежуток времени солнечная лучевая энергия, попадающая на поверхность листа, уменьшается до 1,6%, а при амплитуде колебания до 30 градусов соответственно количество лучевой энергии на поверхности листа растения уменьшается до 14%. Установлено, что суммарное количество солнечной лучевой энергии во время пульсации не зависит от частоты колебания листа за одинаковый промежуток времени. Пульсации солнечной лучевой энергии при изменении положения листа растения относительно Солнца вызывают температурные пульсации в листе.


1977 ◽  
Vol 19 (81) ◽  
pp. 677-678
Author(s):  
V.G. Konovalov

AbstractA computer method for calculating the total melting from May to October has been developed both for a single glacier and for a glacial area. In the second case (which is the more interesting and important for hydrology and glaciology) it is necessary to calculate some characteristics of an “average" glacier of the region using morphometric characteristics included in the Catalogue of the U.S.S.R. glaciers. These are: glacier area; average area of moraine on the glacier; weighted average of heights of upper and lower ends of a glacier and weighted average of mean height of firn line. It is also necessary to obtain data on glacier area distribution by height, precipitation data, and data on air temperature and cloudiness at meteorological stations.In addition to defining typical glacial regions within the limits of the glacial area considered and determination of the “average" glacier characteristics listed above, preparation of the computer programme includes (a) definition of precipitation dependence on orography height and calculation of appropriate parameters, (b) reduction (if necessary) of data obtained from the meteorological station nearest to glacial area to a more prolonged range, (c) calculation of a special balance index of accumulation and melting of seasonal precipitation which makes it possible to define maximum excess of seasonal snow line over the “average" glacier terminus in separate years, and (d) computation of total solar radiation occuring in clear days during May to October.In the course of computation on computer the following operations are realized: (a) determination of an average value of total radiation arriving during months of May to October period given the real cloudiness conditions, (b) calculation of the height of the snow line on the glacier, (c) calculation of quantity and duration of solid atmospheric precipitation which melts between May and October on the glacier surface, (d) estimation of absorbed solar radiation taking account of the differing albedo of glacial surfaces situated above and below the seasonal snow line, (e) calculation of the total melting of glaciers belonging to the given mountain watershed.Checking of the calculational method has been performed using data from Lednik Tsentralnyy Tuyuksu and Lednik Ayutor-2 where numerous ablation stakes were installed. Values of measured and calculated melting agree satisfactorily.


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