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Evaluation of Solar Radiation Transposition Models for Passive Energy Management and Building Integrated Photovoltaics
摘要： Incident solar radiation modelling has become of vital importance not only in architectural design considerations, but also in the estimation of the energy production of photovoltaic systems. This is particularly true in the case of buildings with integrated photovoltaics (PV) systems having a wide range of orientations and inclinations defined by the skin of the building. Since solar radiation data at the plane of interest is hardly ever available, this study presents the analysis of two of the most representative transposition models used to obtain the in-plane irradiance using as input data the global and diffuse irradiation on the horizontal plane, which can be obtained by satellite-based models or ground measurements. Both transposition models are validated with experimental measurements taken in Murcia (southeast of Spain) and datasets provided by the photovoltaic geographical information system (PVGIS) and the National Renewable Energy Laboratory (NREL) for vertical surfaces facing the four cardinal points. For the validation, the mean bias deviation, root mean square error and forecasted skill were used as indicators. Results show that the error rate decreases slightly for clear days. Better results are also obtained by dismissing data with low solar elevation angles so as to avoid shadowing effects from the surroundings in the early and late hours of the day, which affects mainly the performance of the transposition models for west and east surfaces. The results highlight the potential of equator-facing fa?ades in winter time when the received irradiation can be twice as much as the one collected by the horizontal plane. It is also noteworthy that the operating conditions of all fa?ades are mainly low irradiance and medium temperature at these locations.
关键词： PV fa?ades,BIPV,anisotropic sky models,solar irradiance
更新于2025-09-19 17:13:59
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[IEEE 2019 Smart Grid Conference (SGC) - Tehran, Iran (2019.12.18-2019.12.19)] 2019 Smart Grid Conference (SGC) - Introducing a novel method for improving the design of off-grid photovoltaic systems
摘要： Two-color pyrometric methods have been widely used in noncontact temperature measurement area. However, it is difficult to get synchronous monochromatic images for two-color pyrometric formula. Some researches use beam splitter to obtain two or more optical paths to capture the different monochromatic images, but the complex optical paths will bring spatiotemporal matching errors. Another method uses color camera to capture the Red, Green, Blue (RGB) channel images as the RGB monochromatic images, but substituting the Dirac delta function for spectral response function will result in the inaccuracy of the measurement results. In fact, the RGB monochromatic images can be obtained from the color image if the irradiance attenuations from color channel to single wavelength are calibrated. In this paper, a novel 3-D reconstruction method is proposed to measure the temperature distribution of combustion flame. First, the irradiance attenuations are calibrated to calculate the synchronous monochromatic images at R and G wavelengths. Second, the tomographic reconstruction of flame monochromatic emissive power is improved with visual hull restriction so that the energy distribution is more reasonable. Finally, the 3-D temperature distribution is calculated from the reconstructed monochromatic emissive power fields at R and G wavelengths using two-color pyrometric method. The alcohol and butane flames are tested in the laboratory-scale test rig. The experimental results indicate that our approach performs well in flame temperature field reconstruction.
关键词： irradiance,3-D reconstruction,two-color pyrometry,flame temperature distribution,temperature field measurement
更新于2025-09-19 17:13:59
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Optimizing the inclined field for solar photovoltaic arrays
摘要： Existing studies are focused on maximizing the solar energy collection by photovoltaic modules installed on a flat (horizontal) field. This paper presents an analytical model, which considers the tilt angle of the field along with the modules and evaluates the direct solar energy accumulation within a given time period. Validation of the model is performed by comparing the results with measurements obtained from a computer-aided 3D model. Then, various applications of the model are demonstrated for optimizing field and module tilt angles. The simulations were performed at a virtual site in Auckland (New Zealand; latitude: ~36.86?S). For the given dimensions of the field and the modules, the results showed that nearly horizontal modules collect 35% more energy than when they are at the latitude angle. If they are tilted at the latitude angle, increasing the inclination angle of the field above 16? increases energy collection by 48%. A contour plot of energy collection over the specified ranges of tilt angles was developed to help designers choose the best possible combinations. Finally, the monthly and seasonal energy collections are also presented for modules fixed on an inclined field, tilted at latitude angle.
关键词： constrained field,tilt angle,solar potential,solar irradiance,solar PV,inclined array
更新于2025-09-19 17:13:59
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Long-Range Distributed Solar Irradiance Sensing Using Optical Fibers
摘要： Until recently, the amount of solar irradiance reaching the Earth surface was considered to be a steady value over the years. However, there is increasing observational evidence showing that this quantity undergoes substantial variations over time, which need to be addressed in different scenarios ranging from climate change to solar energy applications. With the growing interest in developing solar energy technology with enhanced efficiency and optimized management, the monitoring of solar irradiance at the ground level is now considered to be a fundamental input in the pursuit of that goal. Here, we propose the first fiber-based distributed sensor able of monitoring ground solar irradiance in real time, with meter scale spatial resolutions over distances of several tens of kilometers (up to 100 km). The technique is based on an optical fiber reflectometry technique (CP-φOTDR), which enables real time and long-range high-sensitivity bolometric measurements of solar radiance with a single optical fiber cable and a single interrogator unit. The method is explained and analyzed theoretically. A validation of the method is proposed using a solar simulator irradiating standard optical fibers, where we demonstrate the ability to detect and quantify solar irradiance with less than a 0.1 W/m2 resolution.
关键词： optical time domain reflectometry,photothermal effects,distributed sensing,rayleigh scattering,optical fiber sensors,solar irradiance,solar energy,optical radiation
更新于2025-09-19 17:13:59
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Performance Analysis of Submerged Polycrystalline Photovoltaic Cell in Varying Water Conditions
摘要： Exploring the underwater solar energy by solar photovoltaic (PV) cells leads to a huge advantage by utilizing the humongous space of water covered by the earth’s surface. Even though the amount of solar radiation decreases with the depth of the water, water provides sustainable cooling and cleaning for solar PV cells underwater. There are many challenges and constraints to develop solar PV cells underwater because they are mostly calibrated and amenable to space, dryland, terrestrial, etc., and the solar spectrum is prone to get narrower with the depth of the water. The implementation of solar PV cells underwater is pliable in various commercial and defense applications, such as sensors, water monitoring systems, autonomous vehicles, underwater gliders, etc. In this article, first, a mathematical model has been developed for the solar cell spectrum to incorporate the changes in the solar irradiance with the depth of the water. Furthermore, an experimental setup was designed and implemented to mimic an underwater environment. The performance of the polycrystalline encapsulated solar cell was studied based on the different types of water and the depth of the solar cell underwater. This article manifests that there is a sufficient amount of underwater solar power that can be utilized using PV cells to operate various devices and systems.
关键词： polydimethylsiloxane (PDMS),Photovoltaic (PV) cells,underwater solar power,polycrystalline solar cell,solar spectrum,water salinity,solar irradiance
更新于2025-09-16 10:30:52
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Impact Study on Power Generation from Photovoltaic System due to Change in Local Irradiance and Temperature at Kathmandu Valley, Nepal
摘要： Solar Photovoltaic system has become popular among the renewable energy due to free availability and low maintenance costs. Economically, the decreasing cost from continuous development adds another motive for the use of photovoltaic system. There has been a continuous study regarding the estimation on output of the photovoltaic system, in normal operating conditions. The output is subject to variations due to various environmental factors. The aim of this study is to evaluate how Design of Experiments (DoE) Method is used to model the impact of meteorological data on the electric power generated by the photovoltaic system. In this paper, the simulation and experiment based analysis has been presented and the degree of impact of irradiance and temperature on the output power of the photovoltaic module has been illustrated.
关键词： Irradiance,Design of Experiments (DoE),Photovoltaic,Temperature
更新于2025-09-16 10:30:52
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Reliable long-term performance assessment of commercial photovoltaic modules tested under field conditions over 5 years
摘要： Due to their scalability and global abundance of sunlight, photovoltaic panels are a promising option as a renewable energy source. Implementation of photovoltaic technologies on a large scale requires a careful business-case assessment, aimed at the selection of the technological option most appropriate for the local conditions in terms of long-term performance. For this purpose, five types of modules representative of current options on the market were tested under field conditions for five years at a test facility in Germany. The degradation rates of module performance were computed from the obtained photovoltaic power normalized by both recorded and modeled solar irradiance. The results emphasize the relevance of using modeled irradiance data in addition to recorded solar irradiance in order to extract reliable degradation rates. The available methodological tools still have to be adapted to every dataset for the most accurate result. Eventually, robust degradation rates were extracted from experimental power data, based on modeled clear-sky irradiance, and a combination of aggregation and regression strategies. The results show distinctive degradation behaviors of the five available commercial photovoltaic modules in response to the local conditions.
关键词： performance assessment,photovoltaic modules,field conditions,degradation rates,solar irradiance
更新于2025-09-16 10:30:52
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Effect of Irradiance Measurement Sensors on the Performance Ratio of Photovoltaic Power Plant Under Real Operating Conditions: An Experimental Assessment in Turkey
摘要： The performance analysis of photovoltaic (PV) plants plays an important role in making investment decisions, creating more efficient designs, and in the operation and maintenance decisions in new plants. In addition, performance analysis provides a way to identify real-time operational problems and allows comparisons among different PV plants. Performance of PV plants can be indexed with many parameters, but service providers are giving energy guarantees according to their performance ratio (PR). There are many factors that affect PR, such as irradiation, temperature, wind speed, humidity and soiling. But, the most important factors affecting PR are irradiation and temperature. Hence, both the irradiation and the temperature must be measured correctly. Solar irradiation is usually measured with a pyranometer or reference cell. However, there are differences between the obtained data from these two sensors, which affects the PR significantly. In this study, the PR of an MW PV plant installed in Turkey was investigated. Two types of irradiation sensors (pyranometer and reference cells) and PVGIS program were used. The data were collected every 5 min during 1 year. The data passed through quality control and filtered process and some improper values were removed from the row data set. In addition, new data were written instead of the missing data. PR was calculated by using conventional and corrected method. As a result, the average annual PR is determined to be 81.05%, 79.04% and 78.96% and the corrected PR is determined to be 83.69%, 82.48% and 80.87% using the reference cell, pyranometer and PVGIS program, respectively.
关键词： Solar energy,Uncertainty of measurement sensors,Irradiance sensor,Corrected PR,Performance ratio (PR),Photovoltaic plant
更新于2025-09-16 10:30:52
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Disturbance Characteristics of the Off-Grid Photovoltaic System in the Frequency Range from 9 - 150 kHz with Changing Solar Irradiance and Shading Area
摘要： A solar power plant converts light into electricity using photovoltaics. It uses an inverter to convert DC to AC current to be connected to an AC load. Increasing use of solar panels in household application results in an increase in the use of inverters, in which some might due to the fact that inverters can produce disturbances at a frequency between 9-150 kHz. This study is focused on observing the disturbance characteristics of an off-grid photovoltaic system due to variations of irradiation and shading in the frequency range from 9 - 150 kHz. It is expected that the output of this observation can provide a reference for research in determining the effects on electric power system. This observation provided a shading effect of 0%, 25%, 50%, 75%, and 100% of the photovoltaic area and then conducted observation based on two solar irradiation conditions. Based on the observations, it is identified that in general there are 3 frequency ranges of dominant disturbances, they are: 20-25 kHz, 72-73 kHz, and 144-146 kHz. Their voltage disturbance will decrease with increasing shading area, where at shading conditions of 25% and 50% they will have a value voltage disturbance that tends to be the same as that in the 3 dominant frequency ranges.
关键词： disturbance characteristics,off-grid,shading area,photovoltaic system,solar irradiance
更新于2025-09-16 10:30:52
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An Improved Technique to Estimate the Total Generated Power by Neighboring Photovoltaic Systems Using Single-point Irradiance Measurement and Correlational Models
摘要： A major operational challenge of photovoltaic (PV) systems is the variability in their output power, which is mainly caused by the movements of clouds. This variability can be reduced through building several smaller PV systems, distributed within an area, rather than a single, large PV system, often referred to as the geographic smoothing. This smoothing can be expressed mathematically by the variability reduction index (VRI), which denotes the reduced level of variations in the output power of a group of neighboring PV systems. VRI considers the size of the PV systems, the distances between them, as well as the mathematical correlation model that reflects the timescale, along with the speed, direction and density of the clouds passing over the PV systems. The VRI and solar irradiance, measured at one location, can be used to estimate the power generated by a group of neighboring PV systems. This paper initially compares and assesses various VRI models through their application on a group of 16 small-scale neighboring rooftop PV systems, distributed over a square kilometer area in Brisbane, Australia. Then, a technique is proposed to improve the estimation accuracy of the overall generated power by a group of neighboring small-scale rooftop PV systems. This new technique is validated by comparing the estimated power with the measured power, generated by the investigated PV systems.
关键词： Correlational model,Irradiance,Variability reduction index,Distributed neighboring PV systems
更新于2025-09-16 10:30:52