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Modeling and Experimental Validation of a Low-Cost Radiation Sensor Based on the Photovoltaic Effect for Building Applications
摘要： The energy consumed to cool buildings is very elevated and solar gains represent a high percentage of these cooling loads. To minimize the thermal load it is necessary to control external shading systems. This control requires continuous measurement of solar radiation in different locations of the building. However, for such applications the use of conventional irradiance sensors increases the cost and reduces the profitability of the installation. This paper is focused on the development, modeling, and experimental validation of low cost irradiation sensors based on photovoltaic effect in order to reduce the costs of dynamic external shading devices and to improve the profitability of the system. With this proposal, firstly, small commercial photovoltaic cells have been adapted for use as an irradiation measurement device. Subsequently, quasi-stationary and continuous experimental measurements of these silicon cells, facing south and installed horizontally, have been carried out in Jaén (Spain) in 2009 and 2010. Finally, a nonlinear multiparameter function has been developed to evaluate the irradiance using the electric current generated by the cell, cell temperature, ambient temperature, and absolute humidity. A favorable agreement between the model predictions and experimental data has been observed with a coefficient of determination around 0.996 for all cells.
关键词： thermal drift,solar radiation,photovoltaic,building,solar cells,irradiance estimation
更新于2025-09-23 15:19:57
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Modeling the forecasted power of a photovoltaic generator using numerical weather prediction and radiative transfer models coupled with a behavioral electrical model
摘要： The intermittency of the solar radiation is the big challenger for the management of electrical SMART GRID network. So the forecasting of the solar radiation remains the crucial objective to anticipate the injection of the electrical power produced by a photovoltaic generator. In this study, we use the Numerical Weather Prediction model WRF coupled to a radiative transfer model libRadtran to forecast the global, direct and diffuse solar radiations. The NMM core of WRF model was used to predict the vertical profiles of the atmospheric meteorological parameters such as liquid and ice water concentration, cloud cover, relative humidity, temperature, etc. These data are used as input in libRadtran to calculate the hourly solar radiations components (Direct, Diffuse and Global) in real meteorological situations. The radiation values are obtained on regular geographical grid points. A behavioral electrical power model is used to compute the electrical power produced by a photovoltaic generator located at the Center of Development of Renewable Energy in the city of Algiers in Algeria. The comparative study shows well that the results are very encouraging.
关键词： Solar radiation,Photovoltaic power,libRadtran,WRF
更新于2025-09-23 15:19:57
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Economic feasibility of solar power plants based on PV module with levelized cost analysis
摘要： In this study, the cost analysis of solar power system, where is located in Elaz??, Turkey is calculated according to levelized cost analysis method. In the economic feasibility studies carried out by the firms, many parameters such as interest rates, cost of money, detailed sunshine duration, monthly net profit-loss status in one year, cost of investment according to changing interest rates are not taken into consideration. All these parameters, which were not considered by the firms, have been calculated in this study. The payback period of investing in the solar power plant is calculated as 13 years, the payback period of it is calculated as an average of 6.6 years by the firms. The annual profit of a 1 MW solar energy plant is 89,467 US $. Present worth and annual capital cost of the solar power plant are calculated as 1,156,763 US $ and 1,181,875 US $, respectively. The capital cost flow of the investing in solar power plant is determined as 5.628 US $/h. When the results obtained from this study are evaluated in a general framework, the high interest rates in developing countries will have a negative effect on the investments in the solar power plants.
关键词： forecast solar radiation,Solar energy,photovoltaic,renewable energy,economic feasibility
更新于2025-09-19 17:15:36
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A novel flux mapping system for high-flux solar simulators based on the indirect method
摘要： It is an important and challenging work to measure the energy flux density distribution of the concentrated radiation during the concentrating solar power applications. In order to evaluate the performance of a multi-lamps high-flux solar simulator, a novel flux mapping system based on the indirect method has been developed. It features two Lambertian targets. One is a stationary water-cooled Lambertian target where there is a circular hole in the center used to install a flux sensor. The other is a movable Lambertian target used to cover the flux sensor when shooting the concentrated light beam image. This kind of design can obtain the gray value of flux sensor region directly and does not require the interpolation in the sensor-influencing area. The design theory and principle, the hardware implementation and the experimental validation of this flux mapping system have been presented in detail. The repeatability experiments and the error analyses showed that the total relative errors of this flux mapping system were ± 8.1% with a repeatability of 1.1%, and ± 8.5% with a repeatability of 2.7%, for evaluating the flux and the total radiant power, respectively.
关键词： The indirect method,Concentrated solar radiation,High-flux solar simulator,Flux mapping system
更新于2025-09-19 17:15:36
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Estimation of Global Solar Radiation using Modifed Angstrom Empirical formula on the basis of Meterological parameters in Himalaya Region Pokhara, Nepal
摘要： This research work proposes the coefficient equation of modified Angstrom model using sunshine hour and meteorological parameters for the estimation of global solar radiation in Himalaya Region Pokhara (28.220N, 83.320 E), Nepal. This site is about 800.0 m above from the sea level lying just 20.0 km south of the Machhaputre Himalayas. The model coefficients a and b obtained in this research are 0.43 and 0.23 respectively. The performance parameters of the model are: Root Mean Square Error RMSE = 0.13 MJ/m2/day, Mean Bias Error MBE= 0.02 MJ/m2/day Mean Percentage MPE= 5 percent and coefficient of determination R2= 0.70.
关键词： empirical formula,global solar radiation,regression analysis,sunshine hour,clearness index
更新于2025-09-19 17:15:36
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Approaching the Yablonovitch limit with free-floating arrays of subwavelength trumpet non-imaging light concentrators driven by extraordinary low transmission
摘要： Metamaterials based on arrays of subwavelength dielectric structures has recently proved a viable research venue towards the realization of various photonic devices. In the current study we introduce a new approach towards efficient light trapping and the broadband absorption of the solar radiation based on silicon surface arrays composed of subwavelength trumpet non-imaging light concentrators (henceforth, trumpet arrays). In geometrical optics, a three-dimensional trumpet non-imaging light concentrator is a hyperboloid of revolution with an ideal light concentration ratio. We use finite-difference time-domain electromagnetic calculations to examine the optical response of an infinite cubic-tiled substrate-less silicon trumpet array under normal illumination. The absorptivity spectra of trumpet arrays are characterized by strong absorption peaks, some of which are just below the Yablonovitch limit. The enhanced light trapping is attributed solely to efficient occupation of the array Mie modes, and we show absorption enhancement at the near infrared that is an order of magnitude higher than that of optimized nanopillar (NP) arrays. We show superior broadband absorption of the solar radiation in trumpet arrays (with unoptimized geometry) compared with that of optimized NP arrays (~26% enhancement). The higher optical absorption in trumpet array is governed by low transmissivity, in contrast with NP array in which the absorption is governed by low reflectivity. Finally, we show that low reflectivity in trumpet arrays is governed by modal excitations at the upper part of the trumpets (which is also supported by the weak dependency of the reflectivity on the array height), whereas the transmissivity is governed by modal excitations at the lower part of the trumpets.
关键词： non-imaging light concentrators,Mie modes,nano-photonics,broadband absorption of solar radiation,light trapping
更新于2025-09-19 17:15:36
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The effect of dynamic solar heat load on the greenhouse microclimate using CFD simulation
摘要： Indoor greenhouse temperature exceeds tolerable range for plants growth mostly during the summer in Ahvaz-Iran. Attempts for improving ventilation in summer was not adequate despite a huge energy consumption. Computational fluid dynamic models of a full scaled gable greenhouse covered by semitransparent materials among several adjacent greenhouses inside a greenhouse paradise for predicting the dynamics of its microclimate during a day as well as a year 2017-2018 were developed. The accuracy of the models was approved by comparing to the physical experiments and meteorological reports. The results approved the capability of the model for predicting variable solar heat load and higher indoor temperature than ambient in several hours of a day as well as surface heat transfer coefficient of the walls as affected by regional dominant wind profile. This study enhanced the understanding of required solar heat load removal during the hot months while the average temperature exceeds 40 °C for more than 11 hours a day. This finding also indicates the critical periods in which the fan assisted natural ventilation system can be applied to cool down the greenhouse from more than 40 °C to 25 to 35 °C.
关键词： Greenhouse,Temperature distribution,Modeling,Solar radiation,Dynamic microclimate,CFD
更新于2025-09-19 17:15:36
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An LM-BP Neural Network Approach to Estimate Monthly-Mean Daily Global Solar Radiation Using MODIS Atmospheric Products
摘要： Solar energy is one of the most widely used renewable energy sources in the world and its development and utilization are being integrated into people’s lives. Therefore, accurate solar radiation data are of great significance for site-selection of photovoltaic (PV) power generation, design of solar furnaces and energy-efficient buildings. Practically, it is challenging to get accurate solar radiation data because of scarce and uneven distribution of ground-based observation sites throughout the country. Many artificial neural network (ANN) estimation models are therefore developed to estimate solar radiation, but the existing ANN models are mostly based on conventional meteorological data; clouds, aerosols, and water vapor are rarely considered because of a lack of instrumental observations at the conventional meteorological stations. Based on clouds, aerosols, and precipitable water-vapor data from Moderate Resolution Imaging Spectroradiometer (MODIS), along with conventional meteorological data, back-propagation (BP) neural network method was developed in this work with Levenberg-Marquardt (LM) algorithm (referred to as LM-BP) to simulate monthly-mean daily global solar radiation (M-GSR). Comparisons were carried out among three M-GSR estimates, including the one presented in this study, the multiple linear regression (MLR) model, and remotely-sensed radiation products by Cloud and the Earth’s radiation energy system (CERES). The validation results indicate that the accuracy of the ANN model is better than that of the MLR model and CERES radiation products, with a root mean squared error (RMSE) of 1.34 MJ·m?2 (ANN), 2.46 MJ·m?2 (MLR), 2.11 MJ·m?2 (CERES), respectively. Finally, according to the established ANN-based method, the M-GSR of 36 conventional meteorological stations for 12 months was estimated in 2012 in the study area. Solar radiation data based on the LM-BP method of this study can provide some reference for the utilization of solar and heat energy.
关键词： precipitable water vapor,solar radiation,LM-BP neural network,aerosols,clouds
更新于2025-09-19 17:15:36
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Determining combined effects of solar radiation and panel junction temperature on all model-parameters to forecast peak power and photovoltaic yield of solar panel under non-standard conditions
摘要： In the current study, we introduce two methods to extract model-physical parameters of a solar panel using photovoltaic metrics at key points. We use a single-diode circuit to describe a solar panel working under STC. According to the first method, we derive a new transcendental equation connecting series resistance Rs to quality factor η and photovoltaic metrics at key points. Following the second method, we establish a new analytic expression giving series resistance as a function of quality factor and key points coordinates. For both methods, we express parallel conductance Gp, photo-generation current Iph and leakage current Is in terms of quality factor and all photovoltaic metrics. We use quality factor as variational parameter to minimize RMSE between experimental and optimized characteristics. We borrow temperature coefficients from manufacturer data sheet and determine panel radiation coefficients to derive analytical expressions giving variations of photovoltaic metrics at key points as functions of panel junction temperature T and solar radiation S. To investigate dependencies of all model-physical parameters versus T and S, we consider numerical values of model-physical parameters at STC as initial conditions, and resolve the system of non-linear equations linking panel current to panel voltage at key points. We test numerical models established and mathematical expressions derived by specifying to PV solar panels such as KC130GT and SM55 operating at different environmental conditions of ambient temperature and solar radiation. As a result, for arbitrary environmental conditions, predicted characteristics agree with measured characteristics validating thereby our numerical approach.
关键词： Model-physical parameters extraction,Solar radiation effect,Panel junction temperature coefficients,Solar radiation coefficient,Panel junction temperature effect,Current-voltage characteristics
更新于2025-09-19 17:13:59
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Optimization of the areas of solar collectors and photovoltaic panels in liquid desiccant air-conditioning systems using solar energy in isolated low-latitude islands
摘要： The climate conditions of high temperature and humidity in isolated low-latitude islands lead to high energy consumption of air-conditioning throughout the year. Since the area of island is limited and the supply of conventional energy is difficult, the solar radiation acts as an excellent energy resource for solar air-conditioning. Therefore, an important challenge is to optimize the ratio of the area of the solar collectors and photovoltaic panels to ensure the indoor air is maintained within a comfortable range. In this work, a solar-powered liquid desiccant air-conditioning system is considered as a suitable system, and the working principle of the air-conditioning system and the physico-mathematical models of the subsystems were determined. The energy consumption of the proposed system was compared with that of a conventional cooling dehumidification system under different fresh air loads and heat to humidity load ratios. When the installed area is limited, the ratio of the areas of the collector to photovoltaic panel under different load conditions is optimized. Furthermore, the influence of indoor air design parameters on the required installed area of the system was analyzed. The results provide a basis for the application of solar-powered liquid desiccant air-conditioning system in isolated low-latitude islands.
关键词： Intense solar radiation,Photovoltaic panel area,Solar-powered liquid desiccant air-conditioning systems,Solar collector area,High temperature,High humidity
更新于2025-09-19 17:13:59