Solar Radiation Values Research Articles

Applying response surface method to optimize the performance of a divergent-chimney solar power plant

One of the effective tools to generate electricity from solar energy is Divergent-chimney solar power plant (DSPP). Divergent and cylindrical chimneys of solar power plants have different performances considering turbine pressure drop ratio (ft). For the first time, the divergent angle (DA) and solar radiation (SR) interaction effects on ftopt are discussed through applying the Computational Fluid Dynamics (CFD) and Response Surface Method (RSM). FLUENT software is employed to perform 2D axisymmetric numerical stimulation for the Manzanares prototype. The DA, SR, and ft with ranges of 0°–3°, 200–800 W/m2, and 0.2–0.9 are considered, respectively, in the RSM optimization. The outcomes denote that the amount of ftoptvaries from 0.71 to 0.89 continuously, and it is related inversely to the DA and directly to the SR. The maximum efficiency (ηmax) is obtained at ftopt, for different SRs and DAs. It is concluded that the ηmax is enhanced from 0.42% to 0.50%, achieved by increasing the DA and SR values. Furthermore, the quadratic correlation of the ftopt and ηmax in terms of DA and SR parameters are provided. Therefore, the consequences of this research would be a suitable resource for designing optimum turbines for the DSPPs.

Ресурсы солнечной энергии Нахичевани

The presented article examines the issues of energy security of the Nakhchivan Autonomous Republic, which is an integral part of the Republic of Azerbaijan, and the use of renewable energy in its provision. For this purpose, the solar energy resources of the Autonomous Republic were studied. The study used theoretical, computational, observational and comparative analysis methods to estimate solar energy as a renewable energy resource. The main source for assessing the potential of solar energy of the Autonomous Republic — experimental and observation materials of the USSR Hydrometeorological Committee on the Republic of Azerbaijan and NAR for 1960–1980, the results of researches of the Institute of Geography of the Azerbaijan National Academy of Sciences for 1936–1950, Nakhchivan AR experimental-observation materials of the Hydrometeorological Center for 1995–2015, static indicators of Nakhchivan Solar Power Plant for 2016–2017, as well as the results of theoretical and computational research were used. As a result of the study, it was determined that the annual value of total radiation (Q) in the horizontal area was 7541 and 6204 MC/m2, respectively, in the clear and medium cloudy sky. At the same time, the average annual transparency coefficient was 0.8229, 0.811 in winter and 0.897 in summer. The annual value of total radiation (Q) of the horizontal field in the territory of the NAR is higher than in other regions of the country, and the coefficient of transparency of the atmosphere is higher than in other regions, too. At the same time, the duration of solar radiation in the NAR is high and is 2792 hours. Formulas have been proposed to calculate the value of solar radiation falling on a horizontal surface on the basis of many years of experimental and observational materials. Using these calculation formulas, it is possible to calculate the total solar radiation on the horizontal surface for any area of the NAR.

Thermal building upgrade with off-grid PV system: a Polish case

Nowadays, one of the basic requirements for thermally upgraded buildings involves limitation in CO2 emission even by over 90%. To fulfil these criteria, it is necessary to use alternative energy sources and photovoltaics constitutes a reasonable option for this. This paper addresses an analysis of the efficiency and profitability of a photovoltaic system located in the geometric center of Europe-Poland, where the intensity of solar irradiation is not very high compared to other European countries. The difference of total solar radiation density between Poland and Malta is 49.2%, from analysis based on SolarGIS base. The PV Lighthouse calculator was used for global power density and photon current examination for a Polish city and locations of the highest and the lowest solar radiation values, Malta and Finland, respectively. This case study concerns a thermally upgraded building; a gas boiler was replaced by a heat pump supported by an off-grid PV system. To achieve a reduction in CO2 emission of 90%, it is necessary to install 182 PV cells, which generates high investment costs. An investment is entirely profitable with 70% of funding with Simple Pay Back Time, SPBT~7 years although Net Present Value, NPV>0; Internal Rate of Return, IRR=10.6%.

The Surface Energy Budget at Gale Crater During the First 2500 Sols of the Mars Science Laboratory Mission

AbstractWe use in situ environmental measurements by the Mars Science Laboratory (MSL) mission to obtain the surface energy budget (SEB) across Curiosity's traverse during the first 2500 sols of the mission. This includes values of the downwelling shortwave solar radiation, the upwelling solar radiation reflected by the surface, the downwelling longwave radiation from the atmosphere, the upwelling longwave radiation emitted by the surface, the sensible heat flux associated with turbulent motions, and the latent heat flux associated with water phase changes. We then analyze their temporal variation on different timescales and relate this to the mechanisms causing these variations. Through its Rover Environmental Monitoring Station, MSL allows for a more accurate determination of the SEB than its predecessors on Mars. Moreover, the unprecedented duration, cadence, and frequency of MSL environmental observations allow for analyses of the SEB from diurnal to interannual timescales. The results presented in this article can be used to evaluate the consistency with predictions from atmospheric numerical models, to validate aerosol radiative properties under a range of dust conditions, to understand the energy available for solar‐powered missions, and to enable comparisons with measurements of the SEB by the Perseverance rover at Jezero crater.

Experimental Investigation on Performance Parameters Affecting the Efficiency of Water Type PV/Thermal Collectors with Modified Absorber Configurations

In this study, efficiency of water-type photovoltaic/thermal (PV/T) modules that convert solar energy into both electrical and thermal energy were investigated. By using identical photovoltaic (PV) cells, one PV module and five PV/T modules differed in thermal structure with different diameters, amount and layout of absorber tubes, and type of absorber sheets were fabricated with lamination technique. Firstly, the electrical efficiency of all samples under Standard Test Conditions was tested by a sun simulator. Efficiency values were between 12.56% and 12.68% under STC. Furthermore, outdoor tests were carried out to investigate the effect of temperature on PV modules in ambient conditions using PV/T samples. In order to determine the efficiency of the units, parameters such as solar irradiation, voltage and current values, inlet and outlet water temperature and flow rate of PV/T modules and ambient temperature were measured. It was observed that the electrical performance of PV/T modules was higher than that of the PV module due to the cooling effect of water circulation over the cells. PV/T module with the highest thermal efficiency was also determined. Total efficiency value of PV/T modules in outdoor conditions were attained between 60.68% and 67.14%.

Electric power management in a microgrid analyzing photovoltaic arrays and a turbine-generator system

One of the priority objectives of microgrids is to achieve energy self-sufficiency, generally resorting to distributed generation sources and backup systems; however, they are usually connected to conventional electrical networks that ensure supply to the loads. Addressing this problem, this work presents a proposal (managing elements) to minimize the dependence of power from the external electrical system in the months of greatest demand and thus guarantee the supply of the other months. The proposed methodology compares two statistical techniques: central composition design with 20 simulated experimental replicas and regression with 28. In both cases, the monthly average purchased power is analyzed as a primary response and its standard deviation as a secondary. The study variables are seven photovoltaic arrays and the feed characteristics of the turbine-generator storage of the microgrid of the Center for Development of Renewable Energies (CEDER), belonging to the Center for Energy Research, Environmental and Technological (CIEMAT). The results, with high predictive quality supported by indexes of approach to the real values of solar radiation and the operation of the turbine-generator binomial, provide regions where CEDER has the possibility of increasing the capacities of solar systems and/or modifying the geometry of the mini-hydraulics supply according to your specific conditions.

A hybrid metamodel-based method for quick energy prediction in the early design stage

It is generally acknowledged that the decisions made in the early design stage of a building critically affect its performance. To promote sustainability, building simulations are widely used in the early design stage to calculate the building performance and optimize the design. However, the high computational burden limits the application of building simulations in daily design work. This paper proposes a hybrid metamodel-based method to facilitate the rapid assessment of a building's energy demand in the early design stage. This method (1) decomposes a complex building mass into several zones as different metamodel variants and characterizes the total energy demand by summing up the energy demands of all the metamodels; (2) uses the received solar radiation values as metamodel input parameters to describe the surrounding shading and reflection effects; (3) employs GPU acceleration technology to accelerate the radiation calculation and reduce the simulation time; and (4) implements a machine learning (ML) algorithm screening framework to enhance the accuracy of the metamodels. Case studies were conducted to demonstrate the proposed method. The results showed that this method could predict the energy demands of buildings in high-density urban environments with acceptable accuracy in a short period of time, which would allow designers to obtain feedback on the building energy demand immediately in the early design stage and opens up more possibilities for achieving low-energy buildings.

Estimation of Terrestrial Solar Radiation and its Variation with other Meteorological Parameters over Lokoja, Nigeria

The yearly and monthly estimation of terrestrial solar radiation over Lokoja using meteorological parameters of temperature and relative humidity during the period of twenty two years (July 1983 – June 2005) was investigated. The monthly variation of terrestrial solar radiation with meteorological parameters of global solar radiation, temperature, relative humidity and atmospheric pressure were investigated. The results indicated that high values of terrestrial solar radiation were observed during the rainy season than in the dry season. The highest yearly average values of terrestrial solar radiation observed during the period under investigation were found to be in the year 2005 and 1983 with 378.3521 Wm^(-2) and 368.3232 Wm^(-2) respectively. The highest and lowest monthly values of terrestrial solar radiation were estimated during the rainy and dry seasons in the months of May and January with 385.6133 Wm^(-2) and 358.5111 Wm^(-2) respectively. High values of terrestrial solar radiation with relative humidity and atmospheric pressure were observed during the rainy season and low values during the dry season. The reverse is the case for terrestrial solar radiation with global solar radiation and temperature.

Comprehensive feasibility assessment of building integrated photovoltaics (BIPV) on building surfaces in high-density urban environments

Deployment of building integrated photovoltaics (BIPV) requires smart planning to optimise the production of renewable energies, while preserving the aesthetic quality of the urban landscape, especially in densely built-up urban environments. A comprehensive mapping tool is proposed here to investigate the feasibility of BIPV applications, by introducing a quantitative visual impact assessment in addition to the traditional energy yield projections. The concept is tested in a case study of buildings along Orchard Road, the main commercial and tourist boulevard in the South-East Asian city state of Singapore. First, a visibility analysis of each building surface is conducted from the perspective of simulated pedestrians at street-level, based on line-of-sight. This is followed by an assessment of the solar energy harvesting potential based on simulated annual solar irradiation values on the various building surfaces. Lastly, the visibility assessment is overlaid on the 3D solar irradiation map to identify and visualise the most suitable building surfaces for BIPV applications. In addition, the influence of road-side trees on the feasibility of BIPV has been studied. Depending on the degree of visual impact, different strategies are proposed for the optimum deployment of BIPV, ranging from high-efficiency technologies to aesthetic BIPV and media walls. The proposed methodology could evolve as a standard tool for the decision-making process in high-density urban environments and thus further assist in promoting the large-scale adoption of BIPV.

New Control Scheme for Solar Power Systems under Varying Solar Radiation and Partial Shading Conditions

The traditional perturbation and observation (P&O) maximum power point tracking (MPPT) algorithm of a structure is simple and low-cost. However, the P&O algorithm is prone to divergence under solar radiation when the latter varies rapidly and the P&O algorithm cannot track the maximum power point (MPP) under partial shading conditions (PSCs). This study proposes an algorithm from the P&O algorithm combined with the solar radiation value detection scheme, where the solar radiation value detection is based on the solar photovoltaic (SPV) module equivalent conductance threshold control (CTC). While the proposed algorithm can immediately judge solar radiation, it also has suitable control strategies to achieve the high efficiency of MPPT especially for the rapid change in solar radiation and PSCs. In the actual test of the proposed algorithm and the P&O algorithm, the MPPT efficiency of the proposed algorithm could reach 99% under solar radiation, which varies rapidly, and under PSCs. However, in the P&O algorithm, the MPPT efficiency was 96% under solar radiation, which varies rapidly, while the MPPT efficiency was only 80% under PSCs. Furthermore, in verifying the experimental results, the proposed algorithm’s performance was higher than the P&O algorithm.

Solar/wind pumping system with forecasting in Sharjah, United Arab Emirates

This paper demonstrates a water pumping hybrid power system design. The proposed system was designed for water related applications in Sharjah (Latitude 25.29 °N and Longitude 55 °E), United Arab Emirates. The proposed water hybrid system has two primary renewable power systems: solar PV panels and wind turbines. The proposed hybrid system considers the changes in weather conditions (humidity, wind speed, and temperature) since wind speed affects the performance of the wind turbines and solar panels are affected by solar irradiance. The following components are involved in the proposed design: battery (to store the power from solar panels), voltage regulator circuit (for getting stable DC voltage), three-phase rectifier (to convert the reduced AC voltage to DC), three-phase transformer (for reducing the obtained AC voltage), and DC electric motor (the main output of the proposed water pumping system). The proposed water pumping system relies on neural network blocks to achieve weather forecasting by obtaining solar irradiance values from the input temperature, wind speed, and humidity in a span of five years. Both MATLAB and Simulink are used simulate the performance of the proposed system under different weather conditions by changing the values according to the measured weather conditions values over five years.

Total solar irradiance's effect on the performance of empirical models for estimating global solar radiation: An empirical-based review

Many Total Solar Irradiance (TSI) and Solar Constant (SC) values are given and used in the literature, sometimes leading to confusion. The TSI value is relevant and has great importance in engineering and scientific research in energy. In this study, a review has been done to study the TSI and SC concepts. A reevaluation of the TSI and SC is undertaken to consider state of the art. The effect of three different TSI values concerning different locations is studied for estimating global radiation with the Ångström-Prescott (A-P) formulation over Spain. New seasonal A-P coefficient sets are developed for Spain. The good performance for all the 29 stations and seasons and the slight differences observed for the different TSI values employed ensure global solar radiation (GSR) accuracy with the A-P model. The results highlight the local and seasonal A-P coefficient calibration relevance instead of using a single general pair of calibration coefficients. Based on the TSI study, we recommended calculations of solar radiation models to adopt the TSI value equal to 1361 W m−2. The revised TSI is lower than the previous values proposed. Therefore, it is highly recommended to review the value and concept of TSI.

The application of exterior sun shading on an office building in Kuningan Jakarta Selatan

The golden triangle area marked Jakarta city as a business center. Many people interested in land and buildings in this area with one of the reasons by having a strategic location, with no exception for office spaces and buildings. Kuningan, South Jakarta is a Central Business District, which in fact is filled with skyscrapers which mostly uses reflective materials for it’s skin, makes the radiation reflected and increases the temperature in the air and also inside the building. One of few strategies that is effective to prevent heat from radiation is to use exterior sun shading. The method used in this paper is quantitative approach from the simulation results using software to obtain the solar radiation values to determine the ideal sun shading types to be used in the East and West side of the building. The result of this research is the eggcrate and horizontal louvers are the ideal types of exterior sun shading to be used in the East and West side of the building in Kuningan, South Jakarta.

Optimizing of Q-Learning Day/Night Energy Strategy for Solar Harvesting Environmental Wireless Sensor Networks Nodes

This research article presents the application of the Q-learning algorithm in the operational duty cycle control of solar-powered environmental wireless sensor network (EWSN) nodes. Those nodes are commonly implemented as embedded devices using low-power and low-cost microcontrollers. Therefore, there is a significant need for an effective and easy way to implement a machine learning (ML) algorithm in terms of computer performance. This approach uses a Q-learning-based policy implementing a sleep/run switching algorithm driven by the state of charge. The presented algorithm is based on two modes: daylight and nighttime, which is a suitable solution for solar-powered systems. The study includes the complete process of design EWSN node strategy with an optimal reward policy. The presented algorithm was tested and verified on an EWSN node model and a 5-year data set of solar irradiance values was used for the learning process and its validation. As part of the study, we are also presenting the validation in terms of Q-learning parameters, which include the learning rate and discount factor. The result section shows that the overall performance of the presented solution is more suitable for solar-powered EWSN then state-of-the-art studies. Both day/night experiments reached 828 203 measurement/transmission cycles, which is 12.7 % more than in the previous studies using the strategy defined by the state of energy storage.

Estimation of daily global solar radiation based on MODIS satellite measurements: The case study of Adrar region (Algeria)

In solar energy studies, solar irradiance data at a given site are a fundamental input for reliably predicting performance behavior and the potential of solar applications. Unfortunately, this parameter is not measured in many parts of the world, especially in developing nations, because of the lack of measuring facilities. In this paper, an alternative method for resource assessment is proposed and evaluated. In the proposed method, a model satellite-derived solar irradiance technique was implemented to estimate daily global solar irradiance using satellite earth observation data, particularly products derived from NASA's MODerate‐resolution Imaging Spectroradiometer (MODIS). The estimation results were validated with the observed data collected in the Renewable Energy Research Unit in the Saharan Region of Adrar (URERMS) over a three-year period. The effects of cloud cover and solar zenith angle on the daily mean global solar irradiance are studied. The accuracy of the model is evaluated with various statistical parameters (RMSE, R, MBE, MAE). The results show that the correlation between the estimated and measured values of global solar irradiance is significant, and the effect of cloud and solar zenith angle on the estimation is confirmed.

IMPACT OF WEATHER CONDITIONS ON THE ENERGETIC QUALITY OF ACICULATED DRY BRANCHES OF Araucaria angustifolia (Bertol.) Kuntze PRODUCED THROUGHOUT A YEAR

The aciculated dry branches of Araucaria angustifolia, which fall throughout the year by the natural pruning of the species, can be a renewable and sustainable alternative for energy generation and income for rural producers inserted in the Mixed Ombrophilous Forest. This research aimed to energetically characterize these dry branches produced by free-growing trees throughout the year in the Santa Catarina's Plateau Region. Also, it aimed to determine the influence of weather conditions on the energetic quality of the aciculated dry branches. To that end, we demarcated 37 trees by choosing a quadrant according to the radius of the crowns in which the dry branches were collected. Collections happened monthly between June 2018 and May 2019. Subsequently, the biomass's physical, chemical, and energetic properties were determined. A simple correlation between climatic variables and properties was obtained. The main advantage of aciculated dry branches as an energy resource was their low moisture content (18%) and the disadvantages were the high ash content and the low basic density (220 kg.m-3). Except for the moisture content, all the properties of the aciculated dry branches varied throughout the year, and they were influenced by the weather variables. The correlations between the climatic variables and the properties analyzed indicated that the energetic quality of the dry branches was better in the months with the highest values of average temperatures and solar radiation.

Studying the Changes in Solar Radiation and Their Influence on Temperature Trend in Iraq for a Whole Century

Most studies indicated that the values ​​of atmospheric variables have changed from their general rates due to pollution or global warming etc. Hence, the research indicates the changes of direct solar radiation values ​​over a whole century i.e. from 1900 to 2000 depending on registered data for four cities, namely (Mosul - Baghdad - Rutba - Basra. Moreover, attemptsto correlate the direct solar radiation with the temperature values have been ​​recorded over that period. The results showed that there is a decreasing pattern of radiation quantities over time throughout the study period, where the value of direct radiation over the city of Baghdad 5550 w/m2 was recorded in the year 1900, but this ratio decreased clearly to approximately 5400 w/m2 in the year 2000, which is perhaps due to the increase of general pollution rates in the atmosphere. The results also showed that the city of Rutba recorded the highest annual rate of radiation quantities, and Baghdad with Mosul recorded the lowest radiation ratios compared to the rest of the cities, in addition to that there was a large convergence of radiation ratios between them to some extent. The results showed that there is a sharp drop in radiation ratios, specifically in the years1980and 1990. As for the extent of the relationship for solar radiation with temperature levels throughout the study period, it was found that there is an inverse relationship between them, and this confirms that the cause of high temperatures is not because of increased solar radiation, but it may rather due to other reasons such as increased greenhouse gases.

Validation of meteorological and ground-level ozone WRF-CHIMERE simulations in a mountainous grapevine growing area for phytotoxic risk assessment

Ozone is the most damaging phytotoxic air pollutant to crop yield quantity and quality. This study presents the validation of a simulation with the WRF-CHIMERE modelling system in order to assess the risk of phytotoxicity by tropospheric ozone for an important and characteristic Mediterranean crop, i.e. the grapevine. The study region was the Douro wine region in Portugal, which is characterized by a rugged relief and a Mediterranean climate. The simulation covered a reference grapevine growing season in the Northern Hemisphere (from April to September 2017), during which a particular measuring campaign was also carried out. The validation of the meteorological simulations on a daily and hourly time resolution was performed based on data from three weather stations, namely on temperature, global solar radiation, relative humidity, wind speed and direction values. The ozone phytotoxicity was assessed with data from two measuring stations. A specific grapevine growth parameter based on monitored phenological observations was introduced for ozone stomatal uptake assessment. Concerning meteorology, validation statistics were acceptable and within the range of what has been found in other regional climate modelling simulations. Ground-level ozone-based values were calculated for a better assessment of the phytotoxic risk, in particular cumulative standards for vegetation protection. Stomatal flux estimates were within the range of those measured for the local cultivars in the field campaign when there was not severe water stress limitation. Both field and statistically adjusted model values indicate that considerable areas in the Demarcated Douro Region of Portugal can exceed the critical exposure values for vegetation according to current European legislation standards. Moreover, measured and simulated results indicate an ozone impact on grapevine yield and quality in the target region because the exposure- and flux-based indices exceed the criteria based on current open-top-chamber experimental knowledge.

Hybrid solar/wind/diesel water pumping system in Dubai, United Arab Emirates

This paper proposes a hybrid power system design for water pumping system in Dubai (Latitude 25.25 °N and Longitude 55 °E), United Arab Emirates using solar photovoltaic (PV) panels, wind turbines, and diesel generator. The proposed design considers the changes in weather conditions (humidity percentage, temperature in celsius, and wind speed in m/s) that directly affect solar irradiance values which alter the performance of the hybrid system. The proposed design deals with the problem of rare rainy days in Dubai between December and March and the high temperature throughout the year since that makes providing water to rural and isolated zones essential. The proposed system uses voltage regulator to maintain stable DC voltage from the solar power system, battery bank to store the voltage from solar PV panels, three-phase rectifier to convert the AC voltage from wind power system to DC, three-phase step-down transformers to reduce the AC voltage of the wind turbine and diesel generator, and DC electric motor for water pumping output. The system used neural network for solar irradiance forecasting over an interval of 10 years (from 2009 to 2019). The proposed system will be demonstrated using Simulink to show the stability and performance under different weather conditions.

Artificial intelligence application for the performance prediction of a clean energy community

Artificial Neural Networks (ANNs) are proposed for sizing and simulating a clean energy community (CEC) that employs a PV-wind hybrid system, coupled with energy storage systems and electric vehicle charging stations, to meet the building district energy demand. The first ANN is used to forecast the energy performance indicators, which are satisfied load fraction and the utilization factor of the energy generated, while the second ANN is used to estimate the grid energy indication factor. ANNs are trained with a very large database in any climatic conditions and for a flexible power system configuration and varying electrical loads. They directly predict the yearly CEC energy performance without performing any system dynamic simulations using sophisticated models of each CEC component. Only eight dimensionless input parameters are required, such as the fractions of wind and battery power installed, yearly mean and standard deviation values of the total horizontal solar radiation, wind speed, air temperature and load. The Garson algorithm was applied for the evaluation of each input influence on each output. Optimized ANNs are composed of a single hidden layer with twenty neurons, which leads to a very high prediction accuracy of CECs which are different from those used in ANN training.