Comparative studies on energy balance components and their inter relations on soybean crop and bare soil in kharif season at Pune situated in semi-arid tract

Comparative studies of radiation balance components at different growth stages on soybean crop and bare soil were made at Central Agrometeorological Observatory (CAgMO), Pune. Continuous measurements of net, reflected and global solar radiations were made over cropped field as well as over bare soil all throughout the growth phases in kharif season of 1995. Net and reflected radiations and albedo over canopy were higher by 7, 26 and 25 per cent respectively than bare soil. The net short wave (absorbed) radiation and net long wave (out-going) radiation evaluated over the canopy were less than those over bare soil by 5 and 20 per cent respectively. The mean daily net, reflected, net short wave and net long wave (out-going) radiation were 9.86, 3.86, 15.35 and 5.49 MJm-2 respectively and the albedo was 20 per cent over soybean canopy whereas for bare soil they were 9.23, 3.07, 16.15 and 6.91 MJm-2 and 16 per cent respectively. The mean daily global solar radiation during the crop growing season was 19.20 MJm-2. The highest albedo (26 per cent) of the crop recorded in the 10th week after sowing (WAS) was in correspondence to maximum LAI (5.9) observed at pod formation stage.

Optimization Of Thermal Module Solar Photovoltaic Using CFD-Simulation

Photovoltaic panels can directly generate electricity by converting solar energy, but the panels temperature reduce the efficiency of photovoltaic cells. The photovoltaic thermal PVT system technology is used to improve the electrical performance. In this study, the daily and monthly global solar radiation on a horizontal surface for Iraq have been measured and presented then used with PVT water system. ANSYS software is used to simulate the water temperature differences behavior and measure the surface temperature of PVT model using the collected irradiation with the mass flow rate at 0.01 and 0.02 kg per second. The CFID results were validated with previous studies and observed a good agreement. The simulation tests apply a constant input temperature to the PVT system in all the yearly weather conditions in order to enhance the surface temperature. The results observe the PVT thermal efficiency behavior and show the maximum enhancement which is reached to 61% with the mass flowrate 0.03 kg per second and constant low input temperature.

Analysis of solar radiation measurements at EI-Kharga (250 N, 300E), Egypt

Daily global solar. radiation data of EI-Kharga for five year (1984-88) have been processed, analysed and classified into eight radiation levels spaced at an interval of 4.19 MJ m-2 day-l. Mean annual monthly and daily total the diurnal variation, and the frequency distribution of daily totals of global solar radiation are computed and discussed. A correlation between the hourly values of the clearness and diffuse indices were obtained and the recommended correlation ,equations were also given. The, results presented in this analysis are encouraging since they Indicate that periods of several days of low radiation of less than 8.38 MJm , day are rare. This In turn means that the weather sequence variations are not expected, to be of great Importance when considering the storage problems Involved In solar process design.

Novel models for photovoltaic output current prediction based on short and uncertain dataset by using deep learning machines

This paper presents deep learning neural network models for photovoltaic output current prediction. The proposed models are long short-term memory and gated recurrent unit neural networks. The proposed models can predict photovoltaic output current for each second for a week time by using global solar radiation and ambient temperature values as inputs. These models can predict the output current of the photovoltaic system for the upcoming seven days after being trained by half-day data only. Python environment is used to develop the proposed models, and experimental data of a 1.4 kWp PV system are used to train, validate and test the proposed models. Highly uncertain data with steps in seconds are used in this research. Results show that the proposed models can accurately predict photovoltaic output current whereas the average values of the root mean square error of the predicted values by the proposed LSTM and GRU are 0.28 A and 0.27 A (the maximum current of the system is 7.91 A). In addition, results show that GRU is slightly more accurate than LSTM for this purpose and utilises less processor capacity. Finally, a comparison with other similar methods is conducted so as to show the significance of the proposed models.

Performance Evaluation of Temperature-Based Global Solar Radiation Models—Case Study: Arar City, KSA

Solar radiation is considered the main renewable energy source which reshapes the global sustainability plan for future development. Due to the lack of solar radiation measurements, this work investigates the performance of several temperature-based hybrid solar radiation models combining the parametric, statistical and satellite data approaches to estimate the global solar radiation on a horizontal surface. Over 35 years of meteorological data in the new location, Arar City, KSA (Latitude 30°96′ N and longitude 41°05′ E) are employed to establish and validate the models. These models are validated using two datasets with different averaging time spans to investigate the accuracy and reliability of different models as forecasting tools for the solar radiation. The mostly common statistical indicators are calculated to identify the most accurate model. The results show that Model (1) has the best performance among all models with high reliability as a solar radiation forecasting tool in this new location. This model is also validated against the widely-used datasets, namely NASA, On-Site measurements and PVGIS-SARAH data. The model shows excellent values for statistical indicators with high values of coefficient of determination, R2 > 0.955, presenting the best performance regardless of the time span of the validation datasets.

Prediction of maximum or minimum air temperature in a coastal location in West Bengal

bl 'kks/k i= dk mÌs'; Hkkjrh; rVh; LFkku vFkkZr~ if'peh caxky ds vyhiqj ¼dksydkrk½ esa izsf{kr HkweaMyh; lkSj fofdj.k dh enn ls gjxzhCl fofdj.k QkWewZyk ls rkjh[kokj la'kksf/kr KRS irk djuk gS ftlls fd vkxs ;fn U;wure rkieku ¼Tmin½ Kkr gks rks vf/kdre rkieku ¼Tmax½ dk iwokZuqeku nsus esa vFkok blds foijhr] mi;ksx fd;k tk ldsA HkweaMyh; lkSj fofdj.k ds chp lglaca/k dh x.kuk rkjh[kokj fd, x, /kwi ds ?kaVkokj vk¡dM+ksa ds vkSlr ds mi;ksx ftlesa vkaXLVªkse izsLdkWV QkewZyk ls izkIr fu;rkad as = 0-25 vkSj bs = 0-5 gS] ls dh xbZZ gSA blesa izsf{kr fd, x, HkweaMyh; lkSj fofdj.k vkadM+ksa dk v/;;u fd;k x;k gSA ;g fuf'pr :i ls dgk tkrk gS fd vkaxLVªkse izsldkWV QkewZyk HkweaMyh; lkSj fofdj.k dk lVhd vkdyu djrk gS vkSj ;g lgh ik;k tkrk gSA bl 'kks/k i= esa gjxzhCl fofdj.k QkewZyk ¼ftles KRS = 0-19 fy;k x;k gS½ ls rkjh[kokj izkIr fd, x, vf/kdre rkiekuksa rFkk U;wure rkiekuksa ds vkSlr ¼vkadM+s Hkkjr ekSle foKku foHkkx ds vyhiqj] dksydkrk ftyk & 24 ijxuk ds dk;kZy; ls izkIr½ dk mi;ksx djds HkweaMyh; lkSj fofdj.k ds chp lglaca/k dh x.kuk dh xbZ gS vkSj bldk v/;;u izsf{kr HkweaMyh; lkSj fofdj.k ds lkFk Hkh fd;k x;k gSA rkjh[kokj la'kksf/kr KRS dh x.kuk gjxzhCl fofdj.k QkewZyk ls dh xbZA blesa HkweaMyh; lkSj fofdj.k ds izsf{kr vkadM+ksa] rkjh[kokj vf/kdre rkiekuksa vkSj U;wure rkiekuksa ds vkSlr mi;ksx esa fy, x, gSaA bls fdlh LVs'ku ds vf/kdre rkiekuksa vkSj U;wure rkieku vkadMksa ds rkjh[kokj KRS ds mi;ksx ds }kjk vkl ikl ds {ks=ksa ds ok"iksRltZu ds fy, HkweaMyh; lkSj fofdj.k dk vkdyu djus ds fy, Hkh mi;ksx esa yk;k tk ldrk gSA The objective of this study is to find the date wise corrected KRS from the Hargreaves Radiation formula with the help of observed global solar radiation for the Indian coastal location namely Alipore (Kolkata) in West Bengal so that subsequently it can be used for predicting maximum temperature Tmax if minimum temperature Tmin is known or vice-versa. The correlation between the global solar radiation calculated by using date wise average sunshine hour data with constants as = 0.25 and bs = 0.5, from Angstrom Prescott formula with the observed global solar radiation data was studied. The assertion that the Angstrom Prescott formula gives nearly accurate estimation of global solar radiation has been found to be correct. Correlation between the global solar radiation calculated by using date wise average of Tmax and Tmin (sourced from IMD located at Alipore, Kolkata, District - South 24 parganas) from Hargreaves Radiation formula (taking KRS = 0.19 ) with the observed global solar radiation data was also studied. Date wise corrected KRS by Hargreaves Radiation formula was computed using the observed data of global solar radiation, date wise average of maximum temperature Tmax and minimum temperature Tmin. The date wise corrected KRS can be used for better prediction of Tmax and Tmin. Also it can be used for estimation of global solar radiation for reference evapo-transpiration of the neighbourhood areas by utilizing the date wise KRS with the Tmax and Tmin of the station.

Analysis and correlation of ultraviolet solar radiation from routine meteorological measurements over Egypt

For three years (1990-92) measurements of the monthly average daily global, G, and ultraviolet, UV, solar radiation incident on a horizontal surface at Cairo (30°15'N, 31°17'E) and Aswan (23°58'N, 32°47'E) are presented. processed and analysed. It was found that the computed monthly average daily values for the obtained solar radiation components, G and UV, were (18.1 MJ/m2, 0.55 MJ/m2, for Cairo and (22.1 MJ/m2, 0.71 MJ/m2, for Aswan. The effect of atmospheric dust on the measured solar radiation components is also investigated and discussed. The ratio of the ultraviolet to global radiation (UV/G) are calculated and compared with other sites in the Arabian Peninsula. A regression analysis has been done to find a correlation between G and UV at the selected sites during the three year period and the recommended correlation equations have also been stated. Since the meteorological measurements of UV solar radiation are not available over Egypt. except at Cairo (Lower Egypt) and Aswan (Upper Egypt) stations, our correlation equations can be used to calculate this component from the available global solar radiation measurements at any site in the two zones of Upper and Lower Egypt.