Influence Of Solar Irradiance Research Articles

Photovoltaic power generation data filling model based on tensor decomposition

With the development of new energy and the increase in demand, photovoltaic power generation has received more and more attention. However, due to the susceptibility of photovoltaic power generation to the influence of weather factors, especially the influence of solar irradiation, it is intermittent and fluctuating. Understanding the power generation data of a PV plant has a great effect on the subsequent photovoltaic power generation planning and photovoltaic power plant situation assessment. However, these data are often incompletely recorded due to frequent communication problems or equipment failures. Most current studies focus on photovoltaic power generation predictions, it is still a challenge to speculate the missing data around photovoltaic power plants. In this paper, a context-sensitive tensor decomposition model is proposed to intelligently fill the missing power generation entries. The experimental results show that our model can effectively fill missing data and obtain good results.

Performance analyses on a novel heat pump with a hybrid condenser combined with flat plate micro-channel heat pipe plus TEG and FPV evaporator

A novel heat pump with a hybrid condenser combined with flat plate micro-channel heat pipe (MCHP) plus thermoelectric generator (TEG) and Fresnel photovoltaic (FPV) evaporator is proposed and investigated in this paper. In the previous work, the TEG is inserted between the concentrated PV and absorber plate in the evaporator. Although the TEG can convert the heat stored on PV into electricity, it hinders the heat dissipation of PV, which affects the PV performance. However, if TEG is stalled in the condenser, it could improve the electrical performance and total performance of the system by transforming collected heat into electricity without affecting the heat dissipation of PV. In addition, the MCHP is used to collect heat in condenser to achieve a high heat flow density and high output of TEG. The results show that the addition of TEG in condenser could elevate the electrical and total performance of the system. The TEG not only increases electrical efficiency by 10.83% under 100 W/m2 irradiation, 292.15 K ambient temperature, and 303.15 K water temperature but also increases total exergy efficiency by 6.02% under 100 W/m2 solar irradiation, 286.15 K ambient temperature, and 297.15 K water temperature. The lifting effect is more significant under low solar irradiation. Moreover, the influence of solar irradiation, ambient temperature, and water temperature is also investigated and discussed.

Meteorological factors are associated with asthma prevalence in England

Background/Aim Several exposures contribute to human vitamin D levels including solar irradiation, diet, behaviour and genes. This study was designed to examine meteorological factors that influence the geography of asthma across England, with influence of solar irradiation as primary factor. Methods General practitioner data from 2005 was used to determine the prevalence of asthma in primary care in England. Additional data such as smoking rates and obesity were merged at lower super output level (population ~1000). Meteorological data was obtained from Met Office UK and Joint Research Centre, EU and averages for the period of June 2002 to July 2003 were used. The meteorological data was reprocessed to postcode district level and aggregated to a mean annual measurement. The meteorological data was mapped using ArcMap 10. Associations between climactic factors such as solar irradiation, temperature and humidity and asthma prevalence were tested with a principle component analysis, with spatial auto correlation accounted for. Results Asthma prevalence from GPs in England was 5.9% (95% CI, 5.8-5.9). In the highest UVvitd quartile (2.1-2.5 kJ/m2/day), asthma had an 8% reduction in prevalence compared to the lowest quartile. Similar reductions were found in the higher temperature 0.91 (95% CI, 0.88-94). The opposite was found with relative humidity 1.09 (95% CI 1.05 to 1.12). A combination of high temperature and UVvitd highlighted postcode districts in the South East of England with a climate beneficial to reduced risk asthma, whereas in the North West there was a climate detrimental to asthma with increased risk. Conclusions Weather variables were shown to associate with asthma prevalence in England. Understanding the complex contribution of multiple climatic factors and the relationship with the indoor environment could help to explain the population distribution of asthma.

Thermal analysis of water-cooled photovoltaic cell by applying computational fluid dynamics

Photovoltaic (PV) modules are used for producing electricity in different scales. The efficiency of these modules is highly dependent on their temperature. Owing to the higher efficiency of PV cells at lower temperatures, different thermal management approaches have been suggested in recent years. Water cooling is one of the most efficient methods in PV cells thermal management. In the present article, numerical simulation, on the basis of computational fluid dynamic, is performed to investigate the influence of solar irradiance, ambient temperature and speed of wind on the efficiency and temperature of a monocrystalline cell. The outcomes of simulation revealed that utilizing the applied cooling approach for PV cells in hot ambient temperature and high solar irradiance is more useful. In addition, it is concluded that by employing water for cooling the cell, under the considered conditions, the temperature of the cell can be kept in an appropriate range which prevents its efficiency degradation at high solar irradiance and ambient temperatures. Furthermore, according to the obtained temperature of the cell in different considered cases it is observed that the effect of wind speed is in lower degree of importance compared with solar irradiance and ambient temperature in cases of employing water cooling, while wind speed impact become noticeable when the thermal management approach is not employed. The maximum enhancement in the cell efficiency is approximately 52% in comparison with the reference case without applying cooling.

Performance prediction on a novel solar assisted heat pump with hybrid Fresnel PV plus TEG evaporator

Aiming to make full use of the heat on PV, a novel solar assisted heat pump with hybrid Fresnel PV plus TEG evaporator (FPV/TEG/SAHP) is proposed and the performance is predicted in this paper. As we all know, most irradiation is transformed to heat as the solar irradiation is absorbed by the PV, resulting in high temperature, while the evaporator of the heat pump could provide a lower temperature. Particularly, TEG could complete the conversion from heat to electrical energy under high temperature difference. In this case, we proposed a novel hybrid system, predicted the performance and discussed the influence of solar irradiation, ambient temperature and condensing water temperature. Results show that by adding TEG between PV and evaporator, the heat on PV can be transformed to electrical energy as a second electrical generation, which can complete a maximum lift of 43.77 W electrical energy and increase the electrical efficiency by 1.40% under 800 W/m2 and the COPPVT of the hybrid system can reach 7.89. Besides, for the FPV/TEG evaporator the thermal efficiency, photovoltaic efficiency and the photovoltaic/thermal efficiency could achieve 142.96%, 28.11% and 216.41% respectively under 300 W/m2 irradiation, which all decrease with the increase of the solar irradiation. Additionally, the exergy efficiency of the hybrid system has optimal irradiation varying with ambient temperature or water temperature.

Performance Analysis of a Hybrid Thin Film Photovoltaic (PV) Vacuum Glazing

In this study, we have investigated a hybrid thin film PV vacuum glazing called: ‘PV VG-4L’. The glazing involves an integration between a thin film PV glazing with a double vacuum glazing (both manufactured independently), and an additional layer of self-cleaning coated glass which totalling four layers of glass. The mathematical model of the PV VG-4L designs were developed and numerically solved in MATLAB. To evaluate the performance of the PV VG-4L, the prototype was manufactured and investigated at lab-scale and also under real conditions. Lab-scale experiments were conducted at steady state conditions using a TEC driven calibrated hot box at the Sustainable Energy Research Lab, University of Nottingham, UK. Meanwhile, outdoors, the prototype was tested at a research house at the University of Nottingham, UK. Under the influence of solar irradiance, the electrical performance of the PV-VG and the temperature difference between the surfaces of the glazing were analysed. However, the measurement of U-value under real conditions is not reliable due to the influence of solar irradiance on the heat flux sensor and also due to the absorbed solar irradiance by the thin film PV layer. Nevertheless, during low to zero solar irradiance, the U-value of the prototype can be estimated. The developed model was then validated against the experimental results by direct comparison to the trend of the experimental and theoretical curves obtained, and also by conducting error analysis using root mean squared percentage deviation (RMSPD) method. Testing using the calibrated hot box, adhering closely to ISO 12567 standards, resulted in an average measured total U-value of 0.6 W/m2K which is when compared to a single thin film PV glazing with a typical U-value of 5 W/m2K; the U-value is higher by almost 90%. From the analysis, the computed RMSPD value for the glazing surface temperature and the U-value are 4.02% and 0.92% respectively. Meanwhile, field testing under real conditions with a 0.4 m × 0.4 m PV VG-4L prototype found that 14 W/m2 power can be generated by the PV VG-4L at average solar irradiance of ~600 W/m2. RMSPD computed glazing surface temperatures, electrical power generated under real conditions and U-value are 2.90%, 8.70% and 2.89% respectively. The theoretical and experimental results are concluded to be in good agreement. This study has significant contributions to the knowledge of building integrated photovoltaic PV technology. The mathematical model that has been developed can be used for PV VG-4L design optimisation and also to simulate the performance of PV VG-4L under various conditions. At building efficiency level, the PV VG-4L not only can produce power, but it also has high insulating properties. The promising U-value implies its range of potential applications which can be improved depending on the energy needs and applications, such as for BIPV solar facade (PV curtain walling) in commercial buildings, greenhouses, skylight and conservatory.

An open source model for quantifying risks in bulk electric power systems from spatially and temporally correlated hydrometeorological processes

Variability (and extremes) in streamflow, wind speeds, temperatures, and solar irradiance influence supply and demand for electricity. However, previous research falls short in addressing the risks that joint uncertainties in these processes pose in power systems and wholesale electricity markets. Limiting challenges have included the large areal extents of power systems, high temporal resolutions (hourly or sub-hourly), and the data volumes and computational intensities required. This paper introduces an open source modeling framework for evaluating risks from correlated hydrometeorological processes in electricity markets at decision relevant scales. The framework is able to reproduce historical price dynamics in high profile systems, while also offering unique capabilities for stochastic simulation. Synthetic generation of weather and hydrologic variables is coupled with simulation models of relevant infrastructure (dams, power plants). Our model will allow the role of hydrometeorological uncertainty (including compound extreme events) on electricity market outcomes to be explored using publicly available models.

Artificial neural network modeling and analysis of photovoltaic/thermal system based on the experimental study

A Photovoltaic/Thermal (PV/T) system combines PV and thermal collector, which is considered promising technology especially for building integrated PV/T system. The PV/T cooling systems using water, water-PCM and nanofluid/nano-PCM moves through the cooling pipes were investigated, in this study. However, this paper focuses on testing different PV/T systems (conventional PV, water-based PVT, water-nanofluid PVT, and nanofluid/nano-PCM) under the same conditions and environment using one artificial neural network (ANN) based Multi-Layer Perceptron (MLP) system. Also, investigate the differences in the efficiency of these systems on both thermal and electrical when using only one simulation system (MLP). The proposed ANN approach proved that using of nanofluid/nano-PCM was enhanced the electrical efficiency from 8.07% to 13.32% and its thermal efficiency reached 72%. Also, the voltage was improved significantly. Many measurement methods were used for validating the results of the proposed ANN model like the Mean Absolute Error (MAE), Mean Square Error (MSE), Correlation (R), and coefficient of determination (R2). The proposed ANN model achieved a final MSE of 0.0229 in the training phase and 0.0282 in the cross-validation phase. The sensitivity analysis showed that the influence of solar irradiation and Amb-temp almost has a constant effect on electrical efficiency. However, the Ambient temperature had a significant impact on thermal efficiency. The results of the network were consistent with the experimental results of the current study and published works.

Energetic and exergetic analyses on structural optimized parabolic trough solar receivers in a concentrated solar–thermal collector system

High collecting temperature in parabolic trough collectors (PTCs) induces considerable radiative heat loss of solar receivers, which causes significant negative effects on heat-collecting efficiency. Structural optimized solar receivers with inner radiation shield achieved superior thermal performance for reducing heat loss. Based on widely commercial EuroTrough and PTR70 solar receivers, the optimized solar receivers are numerically applied to a small thermal-collection field with 72 m loop using molten salt as heat transfer fluid to validate their enhanced overall performance. Mathematical models relying on spectrum parameter calculation and working fluid volume unit method are established to simulate the energetic and exergetic performances of the solar receivers. The influence of solar irradiance on parabolic trough collector system is studied, and all-day system efficiencies in different areas in China are investigated to validate the performance of the proposed solar receivers in real condition. Results show that the PTCs with novel solar receivers exhibit outstanding energetic and exergetic performances compared with conventional receivers. The heat loss reduction percentage of the novel receivers reaches approximately 24.0% when the absorber temperature is 600 °C. The heat-collecting efficiency and exergetic efficiency are effectively raised by 7.1% and 4.7%, respectively, at an inlet temperature of 580 °C.

Comparison of short-term solar irradiance forecasting methods when weather conditions are complicated

Although the output of a photovoltaic power generation system is significantly positively correlated with solar irradiance, the latter variable is intermittent, random, and volatile. Volatility in solar irradiance is particularly marked when weather conditions are complex, and so, this factor has proved to be difficult to predict. A neural network (NN)-based approach is applied for short-term predictions in this study based on a timescale that encompasses the amount of irradiance each hour throughout the next day. Thus, a backpropagation NN (BPNN), a radial basis function NN (RBFNN), and an Elman NN (ENN) were selected for use in this analysis. A predictive model was established to evaluate the accuracy of different approaches, given variable meteorological conditions. To reduce the influence of solar irradiance, samples used for forecasts were subdivided into spring, summer, fall, and winter, and the forecast results of sunny and rainy as well as cloudy days in different seasons were investigated. The results of this study reveal that the predictive accuracies of the BPNN and RBFNN were poor on rainy and cloudy days, while the efficiency of the ENN was high and stable in variable meteorological conditions.

Numerical analysis of a multi-channel active cooling system for densely packed concentrating photovoltaic cells

The efficiency of concentrating photovoltaic cells (CPVs) is highly affected by the cell temperature. The main problems for the cooling devices are insufficient heat dissipation and uneven heat distribution. In this study, a novel cooling manifold with multi-channels for densely packed CPVs were proposed and numerical investigated. The effects of coolant type, inlet flow rate and channel dimensions on the cooling performance of the manifold heat sink device were examined. The influence of solar irradiance was also investigated at four solar terms in Shenzhen, China. The results show that great cooling performance and temperature distribution uniformity can be achieved by the novel cooling manifold. Thermal resistance of the studied manifold is also lower than those reported in the literature.

Martian ionosphere observed by Mars Express. 2. Influence of solar irradiance on upper ionosphere and escape fluxes

We present multi-instrument observations of the effects of solar irradiance on the upper Martian ionosphere and escape fluxes based on Mars Express measurements obtained over almost 12 years. It is shown that the variations in the upper ionosphere caused by solar irradiance lead to significant changes in the trans-terminator fluxes of low-energy ions and total ion losses through the tail. The observed dependence of the electron number density in the upper ionosphere at altitudes above 300 km on solar irradiance implies that the ionosphere at such altitudes was denser by a factor of ten during the periods of solar maxima in solar cycles 22–23. Correspondingly, the trans-terminator fluxes of cold ions and escape fluxes through the tail were also significantly higher. We estimate an increase of total ion losses through the tail during these solar maxima by a factor of 5–6.

Photothermal performance of an amorphous silicon photovoltaic panel integrated in a membrane structure

The amorphous silicon photovoltaic (a-Si PV) cells are widely used for electricity generation from solar energy. When the a-Si PV cells are integrated into building roofs, such as ETFE (ethylene–tetrafouoroethylene) cushions, the temperature characteristics are indispensible for evaluating the thermal performances of a-Si PV and its constructions. This temperature value is directly dependent on the solar irradiance, wind velocity, ambient temperature and installation form. This paper concerns the field experiments and numerical modeling on the temperature characteristics and temperature value of the a-Si PV integrated in a double-layer ETFE cushion structure. To this end, an experimental model composed of two a-Si PV cells and a double-layer ETFE cushion was developed, and the corresponding experiments were carried out under two typical weather conditions (summer sunny and summer cloudy). The theoretical thermal model was developed based on an energy balance equation taking the short wave radiation, long wave radiation, convection and generated power into account. The measured solar irradiance and air temperature were used as real weather conditions for the thermal model. The corresponding differential equation of the a-Si PV temperature varying with the solar irradiance and air temperature was solved by a newly developed program based on the numerical method. The measured results show that the influence of solar irradiance on the temperature is much more significant than the other parameters, and the maximum temperature variation under sunny conditions is greater than that under cloudy conditions. The comparative study between the experimental and numerical results shows the correct predictions of the a-Si PV temperature under the sunny and cloudy conditions. The maximum difference is 3.9 °C with the acceptable reasons of the solar irradiance fluctuation and the PV thermal response time. These findings will provide useful observations and explanations for evaluating the PV and building performances in relation to temperature.

Solar irradiance dictates settlement timing and intensity of marine mussels.

Identifying the environmental factors driving larval settlement processes is crucial to understand the population dynamics of marine invertebrates. This work aims to go a step ahead and predict larval presence and intensity. For this purpose we consider the influence of solar irradiance, wind regime and continental runoff on the settlement processes. For the first time, we conducted a 5-years weekly monitoring of Mytilus galloprovincialis settlement on artificial suspended substrates, which allowed us to search for interannual variability in the settlement patterns. Comparison between the seasonal pattern of larval settlement and solar irradiance, as well as the well-known effect of solar irradiance on water temperature and food availability, suggest that solar irradiance indirectly influences the settlement process, and support the use of this meteorological variable to predict settlement occurrence. Our results show that solar irradiance allows predicting the beginning and end of the settlement cycle a month in advance: Particularly we have observed that solar irradiance during late winter indirectly drives the timing and intensity of the settlement onset, Finally, a functional generalise additive model, which considers the influence of solar irradiance and continental runoff on the settlement process, provides an accurate prediction of settlement intensity a fortnight in advance.

Influence of solar irradiance on underwater temperature recorded by temperature loggers on coral reefs

AbstractThe use of miniaturized digital temperature logging devices on coral reefs is increasing dramatically due to the threat of global warming. Shallow coral reef environments are characterized by extremely high solar radiation and highly transparent seawater, raising the possibility of solar heating of devices deployed in these settings. In this study, we compared temperature measurements under a variety of shading treatments to investigate the potential error associated with high irradiance levels in shallow, clear waters. Results of this experiment showed that mid‐day water temperature readings by unshaded loggers were significantly higher by 2.2°C on average compared with shaded loggers. Loggers shielded with reflective tape showed less error but still reported significant heating, with water temperatures that were on average 0.15°C higher than shaded loggers. There were no significant differences among shade treatments during nighttime hours, indicating that irradiance is the source of the errors documented here. Care must be taken to shield temperature loggers from irradiance while providing good circulation of water around the sensors. One option is to place the loggers in a naturally occurring, cryptic or shaded habitat on the reef. When deployed in open reef areas, in mesocosms, or in experimental aquaria, loggers can be shielded in protective, opaque plastic tubes that are open at both ends.

Power Quality Analysis of Integration Photovoltaic Generator to Three Phase Grid under Variable Solar Irradiance Level

Objective of research is to analyze the influence of solar irradiance and integration of photovoltaic (PV) generator to power quality of three phase grid on the constant temperature and load, based on changes in some level of integration of PV generator. Power quality aspects studied are fluctuation or changing, and harmonics of voltage and current on eight scenarios PV generator connected to three-phase grid, using passive filter circuit model double band pass (double tuned). Research shows that voltage and current values on the PCC bus before use double tuned passive filter on the condition only connect single generator is still stable. However, if the PV generator connected to the three phase grid, amounted to more than one generation, voltage and current grid becomes unstable (fluctuation). At the level of solar radiation remains, the greater number of PV generators connected to the grid three-phase, then the values of voltage and current THD increases. At the level of solar irradiance increases, average THD of voltage and current grid also increased. Avarage THD of voltage and current grid is reduced after double tuned passive filter installed. Therefore, double tuned passive filter able to improve profile of voltage and current THD grid as a result of the integration of a number of PV power generators in three-phase grid according IEEE Standard 519-1992. Simulation and analysis of this research use Matlab/Simulink.

Evaluation of photovoltaic panel temperature in realistic scenarios

Photovoltaic (PV) panel temperature was evaluated by developing theoretical models that are feasible to be used in realistic scenarios. Effects of solar irradiance, wind speed and ambient temperature on the PV panel temperature were studied. The parametric study shows significant influence of solar irradiance and wind speed on the PV panel temperature. With an increase of ambient temperature, the temperature rise of solar cells is reduced. The characteristics of panel temperature in realistic scenarios were analyzed. In steady weather conditions, the thermal response time of a solar cell with a Si thickness of 100–500μm is around 50–250s. While in realistic scenarios, the panel temperature variation in a day is different from that in steady weather conditions due to the effect of thermal hysteresis. The heating effect on the photovoltaic efficiency was assessed based on real-time temperature measurement of solar cells in realistic weather conditions. For solar cells with a temperature coefficient in the range of −0.21%∼−0.50%, the current field tests indicated an approximate efficiency loss between 2.9% and 9.0%.

Evidence of Atlantic Multidecadal Oscillation in the magnetic properties of Alpine lakes during the last 2500 years

We re-analyzed rock-magnetic data of lake sediments from the Alpine region, which were previously recognized as sensitive climate proxy records, in search of decadal climate variability. Different methods of spectral analysis applied to the rock-magnetic data from two independent lake records show the presence of a coherent and statistically significant periodicity with a period of about 50–60years. The frequency-filtered signal of this component co-varies with the instrumental record of the Atlantic Multidecadal Oscillation (AMO) over the last 110years with a negligible phase shift. After having tested and ruled out the possible influence of solar irradiance in the putative AMO frequency band, based on spectral properties, we suggest that a significant influence of AMO in the Alpine region extends back in time for at least two millennia. Comparison of the amplitude of the AMO record with that of the Younger Dryas/Holocene transition suggests that AMO fluctuations played a significant role in pacing the past variability of the Alpine climate.

Future development promise for plastic-based solar electricity

Plastic-based photovoltaic (PV) technology, also known as organic photovoltaic (OPV), has the development promise to be one of the third PV generation technologies, practically where sunlight reaches a surface area both indoors and outdoors. This paper presents the economic forecast for solar electricity using OPV technology based on a 1 kWp domestic system. With reference to OPV roll-to-roll manufacturing, the paper discusses lifetime, efficiency, and costs factors of this emerging PV technology. Taking an outlook of historic PV technology developments and reflect future anticipated technology developments, the future levelised electricity cost is calculated using system life cycle costing techniques. Grid parity at levelised electricity cost below 25 c/kWh may already be reached within 10 years' time, and the technology would have been widespread, assuming a typical southern Europe average solar irradiance of 1700 kWh/m2/year. The influence of solar irradiance and the way the module performs over long periods of time expecting various degradation levels is studied using sensitivity analysis. Eventually, the financial attractiveness to mature silicon-based PV technology may decline suddenly as financial support schemes such as the popular Feed-in-Tariffs dry out. This would give rise to other promising solutions that have already been proven to be less energy intensive and cheaper to produce but may require a different integration model than present technologies. This paper demonstrates that under no financial support schemes emerging PV technologies such as OPV will manage to attract business and further developments. Copyright © 2015 John Wiley & Sons, Ltd.

Evaluation of the ECHAM family radiation codes performance in the representation of the solar signal

Abstract. Solar radiation is the main source of energy for the Earth's atmosphere and in many respects defines its composition, photochemistry, temperature profile and dynamics. The magnitude of the solar irradiance variability strongly depends on the wavelength, making difficult its representation in climate models. Due to some deficiencies in the applied radiation codes, several models fail to show a clear response in middle stratospheric heating rates to solar spectral irradiance variability; therefore, it is important to evaluate model performance in this respect before doing multiple runs. In this work we evaluate the performance of three generations of ECHAM (4, 5 and 6) solar radiation schemes by a comparison with the reference high-resolution libRadtran code. We found that all original ECHAM radiation codes miss almost all solar signals in the heating rates in the mesosphere. In the stratosphere the two-band ECHAM4 code (E4) has an almost negligible radiative response to solar irradiance changes and the six-band ECHAM5 code (E5c) reproduces only about half of the reference signal, while representation in the ECHAM6 code (E6) is better – it misses a maximum of about 15% in the upper stratosphere. On the basis of the comparison results we suggest necessary improvements to the ECHAM family codes by the inclusion of available parameterizations of the heating rate due to absorption by oxygen (O2) and ozone (O3). Improvement is presented for E5c and E6, and both codes, with the introduced parameterizations, represent the heating rate response to the spectral solar irradiance variability simulated with libRadtran much better without a substantial increase in computer time. The suggested parameterizations are recommended to be applied in the middle-atmosphere version of the ECHAM-5 and 6 models for the study of the solar irradiance influence on climate.