Transposition Model Research Articles

Determining the Least Risky Solar Radiation Transposition Model for Estimating Global Inclined Solar Irradiation

Solar energy is considered one of the most important energy resources and a key component in addressing major energy challenges worldwide. Therefore, solar radiation data is crucial for many solar energy applications. Due to the lack of measurements at times due to logistical challenges, mathematical transposition models are often used to compensate for this deficiency. This paper presents an analytical study to identify the least risky transposition model for estimating solar radiation on inclined surfaces among six commonly used models in scientific literature, for several regions around the world (Berlin, Rome, Tripoli, N'Djamena, Yandou). Total horizontal solar radiation intensity data was obtained from the Solargis platform for the study regions, carefully selected to represent latitude variations and longitudinal alignment. The proposed approach was applied to these regions for six transposition models and multiple different tilt angles ranging from (90°-10°) to determine the least risky model for use in each region at each solar panel tilt angle. The study results show significant variation among the studied regions, with a notable difference in annual inclined solar radiation values between regions using transposition models, with the discrepancy increasing at higher latitudes. The results indicate that the Perez model is the least risky and dominant model in Tripoli, while in Berlin, the Liu & Jordan model was the least risky at tilt angles between 40°-10°, with the Perez model being the least risky at tilt angles greater than 40°. This study is expected to enhance the accuracy of solar radiation estimation, thus bolstering confidence in assessing the economic and environmental efficiency of solar energy systems.

Assessing the performance of physical transposition models in photovoltaic power forecasting: A comprehensive micro and macro accuracy analysis

Accurate power prediction is crucial for the design, simulation, and performance assessment of Photovoltaic (PV) systems. Achieving this accuracy relies significantly on the precise plane-of-array (POA) irradiance data, which is seldom directly measured. To mitigate this limitation, transposition models have been developed to estimate POA irradiance. Numerous studies have evaluated the performance of these models using horizontal irradiances and POA measurements from specific locations. However, the absence of POA measurements poses a significant challenge to using the proposed methods in transposition model evaluation. Moreover, these studies have overlooked the critical role of POA data in predicting PV power.This study addresses these challenges by assessing the performance of thirty two transposition models within a detailed PV power forecasting framework. A comprehensive micro- and macro-level accuracy evaluation is conducted using predicted and ground-measured energy data from three distinct PV systems in different countries. The evaluation is carried out across hourly, daily, monthly, and annual time scales using four distinct statistical metrics under all-sky and the four sky-conditions.The simulation results validate the effectiveness of the proposed approach in assessing the transposition models in the absence of POA irradiance data. Consistent with previous studies, the findings reaffirm the dependence of transposition model performance on location, climate, time, and cloud cover. Furthermore, the statistical analyses identify the best-performing transposition models for each case study under all-sky and sky-conditions scenarios, providing practical guidelines for model selection.

Solar Energy Received on Flat-Plate Collectors Fixed on 2-Axis Trackers: Effect of Ground Albedo and Clouds

This study investigates the performance of isotropic and anisotropic diffuse models to estimate the total solar energy received on flat-plate collectors fixed on dual-axis trackers. These estimations are applied at twelve sites selected in both hemispheres with different terrain and environmental conditions. The diffuse (or transposition) models used in this study are the isotropic Liu-Jordan (L&J), Koronakis (KOR), Badescu (BAD), and Tian (TIA), and the anisotropic Hay (HAY), Reindl (REI), Klucher (KLU), Skartveit and Olseth (S&O), and Steven and Unsworth (S&U). These models were chosen because of their simplicity in the calculations and minimum number of input values. The results show that a single transposition model is not efficient for all sites; therefore, the most appropriate models are selected for each site under all, clear, intermediate, and overcast conditions in skies. On the other hand, an increase in the ground albedo in the vicinity of the solar installation can increase the annual inclined solar availability on a two-axis tracker by at least 9% on average. Further, a linear dependence of the annual inclined solar energy on the variation of the ground albedo was found. Also, a linear relationship exists between the annual diffuse-fraction and cloud-modification factor values at the 12 sites.

Estimation of the solar radiation intensity on photovoltaic surfaces using anisotropic Models, investigation of influence of tilt angles and solar trackers: A case study for the southeastern of Türkiye

The estimation of total solar radiation (TSR) intensity is crucial for the performance, design, and economic assessment of photovoltaic (PV) energy systems operating in different geolocations and climates. Various transposition Models can be utilized in performance calculations for PV systems in the estimation of TSR on tilted and tracked PV surfaces. Solar tracking equipment can be applied to optimize the TSR gathered by solar PV surfaces. In addition, energy gain can be considerably increased with the use of optimally tilted PV surfaces. This study aims to perform a reliable estimation of TSR for fixed and tracked PV surfaces by applying Hay-Davies, Klucher, Reindl, HDKR, and Perez anisotropic transposition Models over a specific period in Şanlıurfa Turkey. This study does not identify the best anisotropic Model, but with a relative cross-comparison, it points out the values of high variability in outputs and disagreements between different Models. The study highlights the potential of using multiple transposition Models to provide more robust estimates for the annual, seasonal, and monthly solar energy gain in desired geolocations. The annual optimal tilt angle (OPTA) for Şanlıurfa province is estimated to be 30°-31°, which is close to the latitude but below the latitude (6°-7°) of the respective geolocation. The monthly OPTA throughout the year is between 3° in July and 64° in December. It is revealed that the loss in annual TSR does not surpass 0.5% due to the 5° offset of the tilt angle from the OPTA of fixed PV surfaces. The gain in annual TSR for a fixed surface compared to a horizontal surface is estimated to be between 6.05% and 8.24%. The gain in annual TSR for a north-south oriented single-axis tracker (the axis of rotation is on the east-west plane) is estimated between 22.03% and 25.68%, whereas for a dual-axis tracker, it is estimated between 31.49% and 36.66%. It is inferred that, compared to a single-axis tracking, a dual-axis tracking can yield approximately 8.84% more energy. In light of this research, it is recommended that the solar energy potential of the Şanlıurfa can be significantly enhanced by installing tracking systems for maximal generation of solar energy. In the absence of a tracking system, the annual OPTA setting of a PV surface can be a typical strategy. On the other hand, this study reveals that some solar parameters involved in anisotropic Models significantly contribute to the quality of the estimation results. The Models presented in this study can be used to accurately estimate TSR on PV surfaces in various implementations in any place of Türkiye and around the world.

Conformational landscape of the type V-K CRISPR-associated transposon integration assembly

CRISPR-associated transposons (CASTs) are mobile genetic elements that co-opt CRISPR-Cas systems for RNA-guided DNA transposition. CASTs integrate large DNA cargos into the attachment (att) site independently of homology-directed repair and thus hold promise for eukaryotic genome engineering. However, the functional diversity and complexity of CASTs hinder an understanding of their mechanisms. Here, we present the high-resolution cryoelectron microscopy (cryo-EM) structure of the reconstituted ∼1 MDa post-transposition complex of the type V-K CAST, together with different assembly intermediates and diverse TnsC filament lengths, thus enabling the recapitulation of the integration complex formation. The results of mutagenesis experiments probing the roles of specific residues and TnsB-binding sites show that transposition activity can be enhanced and suggest that the distance between the PAM and att sites is determined by the lengths of the TnsB C terminus and the TnsC filament. This singular model of RNA-guided transposition provides a foundation for repurposing the system for genome-editing applications.

Regression model optimization using least square algorithms for streamflow data transposition in tropical humid Water Basin

Several projects are under consideration within the Anambra-Imo River Basin (AIRB). However, the location of these projects differs from established gauging stations, necessitating transposition of hydrological information for ungauged sites. This study investigates the transposability of maximum monthly stream records using regression models, employing neighboring stream records as predictors. Ten-year records of five rivers (Adada, Ajali, Otanmiri, Imo, and Ivo Rivers) were deployed to predict one another using a simple regression with five trends (linear, quadratic, cubic, logarithmic, and power). A metric based on compromise programming reveal that Imo records best predict Adada (R2=0.636), Ajali (R2=0.777), and Ivo (R2=0.403) records, while Ajali and Ivo records are the best predictors of Imo (R2=0.703) and Otanmiri (R2=0.349) records, respectively. Linear trends appear to capture relationships among neighboring rivers most effectively. Lack of correlation among neighboring rivers, despite sharing the same basin, suggests that transposition models are catchment-specific and do not support regionalization.

Subhourly Error Analysis of Decomposition–Transposition Model Pairs for Temperate Climates

Subhourly Error Analysis of Decomposition–Transposition Model Pairs for Temperate Climates

Open‐source photovoltaic model pipeline validation against well‐characterized system data

AbstractAll freely available plane‐of‐array (POA) transposition models and photovoltaic (PV) temperature and performance models in pvlib‐python and pvpltools‐python were examined against multiyear field data from Albuquerque, New Mexico. The data include different PV systems composed of crystalline silicon modules that vary in cell type, module construction, and materials. These systems have been characterized via IEC 61853‐1 and 61853‐2 testing, and the input data for each model were sourced from these system‐specific test results, rather than considering any generic input data (e.g., manufacturer's specification [spec] sheets or generic Panneau Solaire [PAN] files). Six POA transposition models, 7 temperature models, and 12 performance models are included in this comparative analysis. These freely available models were proven effective across many different types of technologies. The POA transposition models exhibited average normalized mean bias errors (NMBEs) within ±3%. Most PV temperature models underestimated temperature exhibiting mean and median residuals ranging from −6.5°C to 2.7°C; all temperature models saw a reduction in root mean square error when using transient assumptions over steady state. The performance models demonstrated similar behavior with a first and third interquartile NMBEs within ±4.2% and an overall average NMBE within ±2.3%. Although differences among models were observed at different times of the day/year, this study shows that the availability of system‐specific input data is more important than model selection. For example, using spec sheet or generic PAN file data with a complex PV performance model does not guarantee a better accuracy than a simpler PV performance model that uses system‐specific data.

Can end-to-end data-driven models outperform traditional semi-physical models in separating 1-min irradiance?

As a crucial component of the model chain, which facilitates irradiance-to-power conversion during solar resource assessment and forecasting, separation modeling continues to draw attention in both academia and industry. However, when evaluating even the best separation model today, one can quickly recognize its limited accuracy compared to other energy meteorology models such as transposition models. The task of separating global horizontal irradiance into diffuse and beam components does not seem soluble by any derivative effort aimed at tweaking the existing semi-physical models. As a result, an appealing alternative is to consider end-to-end data-driven models, which have demonstrated predictive capability in scenarios where the volume of data is substantial and the interaction among variables is complex. This work discusses the separation of 1-min irradiance from a data-driven perspective. In this preliminary study, a total of 10 representative data-driven separation models are developed and compared to the state-of-the-art semi-physical models, using a comprehensive 1-min irradiance database that spans five years and covers numerous climate types. The average error of the data-driven models is found to be 15.2% to 22.6% lower than that of the semi-physical models for training locations and 7.9% to 17.6% lower for completely unseen locations. Data-driven models also have significantly lower standard deviations (up to 87.2% even for completely unseen locations), highlighting their robustness. In addition, this work provides a guideline for choosing between data-driven and semi-physical models based on data availability, application needs, computational resources, interpretability, and model adaptability. Furthermore, the study underscores the challenges in accurately predicting the diffuse fraction using available input features and indicates that the incorporation of additional weather-related variables and domain knowledge could enhance the performance of data-driven separation models.

A continuous form of the Perez diffuse sky model for forward and reverse transposition

The Perez 1990 transposition model has emerged as the preferred choice for estimating global tilted irradiance, also known as plane-of-array irradiance. One notable drawback is the Perez model’s reliance on empirical coefficients assigned to discrete bins of the sky clearness parameter, resulting in discontinuities in the calculated tilted irradiance. In this study, we present a novel method to eliminate the discontinuities of the Perez model by replacing the empirical look-up table with a set of six quadratic splines. This is facilitated by transforming the unbounded sky clearness parameter (epsilon) to an equivalent bounded parameter (zeta).Transposition using the original Perez model and continuous Perez–Driesse model are compared for multiple orientations at two locations. The two models produce very similar deviation statistics, meaning the continuous version can be used as a plug-in replacement for the original. Reverse transposition is demonstrated using the Perez–Driesse model together with a new continuous version of the Erbs diffuse fraction model and a simple bisection solution search. This combination achieves a substantially higher success rate than the GTI-DIRINT algorithm in our tests.

Validation of model chains for global tilted irradiance on East-West vertical bifacial photovoltaics at high latitudes

In this paper, a methodology is introduced to identify and validate the most effective model chain to estimate solar irradiance on East-West vertical bifacial photovoltaics (E-W VBPV) at high latitudes. While previous studies mainly focused on the validation of a specific step of the model chain (i.e., decomposition or transposition stage), this work investigates the whole model chain and how the combination of different models influences the results’ accuracy. After a comprehensive review, the 29 decomposition models, which perform the best in the Nordics, and the 25 most common physical and empirical transposition models are selected and combined into 725 model chains. Each model chain is experimentally validated against 1-min data about global tilted irradiance on the front and the rear of E-W VBPV in Turku (Finland). Nine different statistical metrics are calculated to rank the model chains while describing various aspects of the model chain performance (e.g., error magnitude, bias direction, reference data fitting). The main research outcomes indicate that the accuracy and bias of the model chains differ between the East and West sides of the VBPV. Therefore, using a specific model chain for each VBPV side is recommended. In this regard, the Erbs/Steven1 (decomposition model/transposition model) model chain is the top-ranked for the East side, while the Yang2/Hay1 model chain results the best for the West side. Following this, recommendations to select appropriate solar irradiance model chains for future E-W VBPV applications at high latitudes are outlined.

Optimization of seasonal tilt adjustment photovoltaic system in Karbala, Iraq, by using the albedo benefit

This study aims to identify a cost-effective method for enhancing incident irradiation on the collector plane. Two different orientations for photovoltaic (PV) systems have been considered. The PV system is installed with albedo (0.25) on a concrete surface. The system is an off-grid with 690 Wp power, used for office applications with a yearly energy (1068) Khp/yr, located at Karbala Governorate /Iraq. The first orientation has an optimal seasonal tilt angle of 13o and 53o for summer and winter, respectively. In contrast, the second orientation is one-axis tracking, horizontal E-W axis, which produces more output power. To avoid the cost of using a tracking system and improve the amount of the output power of the first system, the old concrete surface of this system was treated with white Portland cement with a higher albedo value of 0.87 and then compared to the parameters (incident irradiation in the collector plane, transposition factor and the product available energy) with a second system. It was using Perez transposition model in PV syst software in this study. The results showed a higher value of comparing parameters when using inexpensive materials like white Portland cement, which improved the output PV system power than the tracking system.

Horizontal-to-tilt irradiance conversion for high-latitude regions: a review and meta-analysis

This review focuses on the solar irradiance model chain for horizontal-to-tilted irradiance conversion at high latitudes. The main goals of the work are 1) to assess the extent to which the literature accounts for decomposition and transposition models specifically developed for high-latitude application; 2) to evaluate existing validation studies for these particular conditions; 3) to identify research gaps in the optimal solar irradiance model chain for high-latitude application (i.e., latitude ≥60°). In total, 112 publications are reviewed according to their publication year, country, climate, method, and keywords: 78 publications deal with decomposition models and 34 deal with transposition models. Only a few models (6) have been parameterized using data from Nordic countries. Here, we compare 57 decomposition models in terms of their performance in Nordic climate zones and analyze the geographical distribution of the data used to parametrize these models. By comparing the Normalized Root Mean Square Deviation coefficients for direct normal irradiation, the decomposition models Skartveit1 and Mondol1 are most effective on one-hour scale and Yang4 on one-minute scale. Recent studies on the empirical transposition models estimating the global tilted irradiation on vertical surfaces show the best performance for Perez4 and Muneer models. In addition, innovative methods such as artificial neural networks have been identified to further enhance the model chain. This review reveals that a validated model chain for estimating global tilted irradiation at high latitudes is missing from the literature. Moreover, there is a need for a universal validation protocol to ease the comparison of different studies.

Spatially resolved generation profiles for building, land and water-bound PV: a case study of four Dutch energy transition scenarios

Abstract. Alongside a transition from steerable and centralized traditional electricity generation to intermittent and more decentralized renewable electricity generation from solar panels and wind turbines, Dutch energy transition scenarios project a widespread deployment of heat pumps and electric vehicles towards 2050. While clearly contributing to the decarbonization of the Dutch energy system, these developments impose challenges regarding electricity supply-demand mismatch and grid congestion. Spatially resolved electricity demand and supply profiles are required to gain a better insight into where and when such problems are likely to occur within the different scenarios. The present paper focuses on Dutch solar energy supply and features the construction of geodatabases of scenario-specific, spatially resolved electricity generation profiles for building, land and water-bound PV. Country-level PV capacities are geographically distributed based on spatial variance in roof PV potential and availability of suitable land and water use areas. Corresponding electricity generation profiles are constructed using historical meteorological measurements, a diffuse fraction model and a anisotropic transposition model. Empirically found performance ratio profiles are applied to account for a multitude of performance loss factors, including shading, dust and inverter efficiency. In 2050, building-bound capacity is projected to show only limited overlap with both land-bound and water-bound PV capacity. On the other hand, regions with considerable water-bound PV capacity also tend to show considerable land-bound PV capacity. Compared to the present-day situation, yearly country-level PV electricity generation is projected to be a factor 18.5, 15.7, or 7.7 higher in 2050 when respectively following the Regional, National or International Steering scenarios.

The Solar Energy Potential of Greece for Flat-Plate Solar Panels Mounted on Double-Axis Systems

The aim of the present work is to investigate the efficiency of flat-plate solar panels in Greece for delivering solar energy. In this study, the solar panels are mounted on a two-axis tracker, which follows the daily path of the sun. In this context, the annual energy sums are estimated on such surfaces from hourly solar horizontal radiation values at forty-three locations, covering all of Greece. The solar horizontal radiation values are embedded in the typical meteorological years of the sites obtained from the PVGIS tool. All calculations use near-real surface-albedo values for the sites, and isotropic and anisotropic models are used to estimate the diffuse-inclined radiation. The analysis provides non-linear regression expressions for the energy sums as a function of time (month, season). The annual energy sums are found to vary between 2247 kWhm−2 and 2878 kWhm−2 under all-sky conditions with the anisotropic transposition model. Finally, maps of Greece showing the distribution of the annual and seasonal solar energy sums under all- and clear-sky conditions are derived for the first time, and these maps constitute the main innovation of this work.

Multi-Stage Validation of a Solar Irradiance Model Chain: An Application at High Latitudes

Evaluating how the sources of uncertainty in solar modelling (e.g., input parameters, developed model chain) can influence the results’ accuracy is one of the main challenges when applied at high latitudes. In this study, a multi-stage validation workflow is implemented around five main stages: data acquisition, data quality check, solar radiation modelling, photovoltaic energy modelling, and experimental validation. Different data sources such as satellite observations, numerical reanalysis, and on-site ground measurements are considered as inputs, while the outcomes from each step of the model chain (e.g., decomposition modelling, transposition modelling, photovoltaic energy modelling) are compared against observations recorded from the solar radiation network at the Norwegian University of Science and Technology (NTNU-Solarnet) in Trondheim (Norway). In the first and second validation stages, the decomposition and transposition models with measured input parameters show the best accuracy indicators, but they do not fulfill the validation criteria. Conversely, in the third validation stage, the photovoltaic energy models with on-site ground measurements as inputs are experimentally validated. In conclusion, at high latitudes, the most accurate results are obtained when monitored solar irradiation data are used instead of satellite observations and numerical reanalysis. Furthermore, the shortest model chain is preferred, with equal data sources.

Surgery and Behavioral Testing in the Tibial Neuroma Transposition Model in Rats.

The tibial neuroma transposition (TNT) is a rat model in which allodynia at the neuroma site (tibial nerve) can be independently evaluated from allodynia at the plantar surface of the hind paw innervated by the intact sural nerve. This TNT model is suitable to test therapies for neuroma pain, such as the potential superiority of certain surgical therapies that are already used in the clinic, or to evaluate new drugs and their effect on both pain modalities in the same animal. In this model, a distal lesion (neurotmesis) is made in the tibial nerve, and the proximal nerve end is transposed and fixed subcutaneously and pretibially to enable assessments of the neuroma site with a 15 g Von Frey monofilament. To assess allodynia over the sural nerve, Von Frey monofilaments can be used via the up-down method on the plantar lateral region of the hind paw. After cutting the tibial nerve, mechanical hypersensitivity develops at the neuroma site within 1 week after surgery and persists at least until 12 weeks after surgery. Allodynia at the sural innervated plantar surface develops within 3 weeks after surgery compared to the contralateral limb. At 12 weeks, a neuroma forms on the proximal end of the severed tibial nerve, indicated by dispersion and swirling of axons. For the TNT model surgery, multiple critical (micro)surgical steps need to be followed, and some surgery practice under terminal anesthesia is advised. Compared to other neuropathic pain models, such as the spared nerve injury model, allodynia over the neuroma site can be independently tested from sural nerve hypersensitivity in the TNT model. However, the neuroma site can be tested only in rats, not in mice. The tips and directions provided in this protocol can help research groups working on pain successfully implement the TNT model in their facility.

Impact on Thermal Energy Needs Caused by the Use of Different Solar Irradiance Decomposition and Transposition Models: Application of EN ISO 52016-1 and EN ISO 52010-1 Standards for Five European Cities

To solve the series of heat balances that EN ISO 52016-1 uses to simulate the dynamic hourly energy requirements of a building, detailed climatic data are required as input. Differently from air temperatures, relative humidity and wind speed, which are easily measurable and available in databases, the direct and diffuse solar irradiances incident on the different inclined and oriented surfaces, which are fundamental for the evaluation of solar gains, must be estimated using one of the many regression models available in the literature. Therefore, in this work, the energy needs of buildings were evaluated with the simplified hourly dynamic method of EN ISO 52016-1 by varying the solar irradiance sets on inclined and oriented surfaces obtained from EN ISO 52010-1 and three other pairs of solar irradiance separation and transposition models. Five European locations and two different window solar transmission coefficients (ggl) were analysed. The results showed that on average, for the heating period and for both ggl, the use of the different methods causes an average error on the calculation of the annual demand of less or slightly more than 5%; while for the cooling period, the average error on the calculation of the annual demand is 16.4% for the case study with ggl = 0.28 and 25.1% for the case study with ggl = 0.63. On the other hand, analysing the root-mean-square-error of the hourly data, using the model contained in TRNSYS as a benchmark, for most of the cases, when varying window orientations, cities and ggl, the model that diverges furthest from the others is that contained in EN ISO 52010-1.

Theoretical model for flat plate solar collectors operating with nanofluids: Case study for Porto Alegre, Brazil

The present work aims to investigate the theoretical model of a flat-plate solar collector considering nanofluids as heat transport medium. For this purpose, solar irradiance decomposition and transposition models have been implemented. Also, the different models for determining the thermophysical properties of nanofluids were implemented and compared with experimental data on these properties. The theoretical model was implemented in Matlab software and validated by comparison with experimental data from a flat-plate solar collector with MgO water. The results show that the maximum relative error was 5.36%, the minimum relative error was 0.20%, and the mean relative error was 2.02% when the model was validated with experimental data for MgO-water nanofluid with volume concentrations between 0 and 1.5%. Therefore, the theoretical model was successfully extended to simulate flat-plate solar collectors with MgO-water nanofluid. A parametric study showed that a nanofluid with a volume concentration of 0.75% MgO exhibited a higher relative increase in thermal efficiency compared to pure water. Moreover, the theoretical model was applied to a case study by simulating the annual performance of the collector in Porto Alegre, Brazil, when it was operated with MgO water. This showed satisfactory effects and great potential for application.

Ongoing transposition in cell culture reveals the phylogeny of diverse Drosophila S2 sublines.

Cultured cells are widely used in molecular biology despite poor understanding of how cell line genomes change in vitro over time. Previous work has shown that Drosophila cultured cells have a higher transposable element content than whole flies, but whether this increase in transposable element content resulted from an initial burst of transposition during cell line establishment or ongoing transposition in cell culture remains unclear. Here, we sequenced the genomes of 25 sublines of Drosophila S2 cells and show that transposable element insertions provide abundant markers for the phylogenetic reconstruction of diverse sublines in a model animal cell culture system. DNA copy number evolution across S2 sublines revealed dramatically different patterns of genome organization that support the overall evolutionary history reconstructed using transposable element insertions. Analysis of transposable element insertion site occupancy and ancestral states support a model of ongoing transposition dominated by episodic activity of a small number of retrotransposon families. Our work demonstrates that substantial genome evolution occurs during long-term Drosophila cell culture, which may impact the reproducibility of experiments that do not control for subline identity.