•Shape based clustering model is proposed for solar radiation prediction.•Effect of various combinations of meteorological parameters is analyzed.•Combination of models give better result in ...comparison to single model.•Sunshine duration is prime parameter for prediction.•Wind speed has least effect on prediction.
Estimation of solar radiation is of considerable importance because of the increasing requirement for the design, optimization and performance evaluation of the solar energy systems. This paper presents the development of pattern similarity based clustering algorithm and its application in solar radiation estimation. In the present work continuous density, Hidden Markov Model (HMM) with Pearson R model is utilized for the extraction of shape based clusters from the input meteorological parameters and it is then processed by the Generalized Fuzzy Model (GFM) to accurately estimate the solar radiation. Instead of using distance function as an index of similarity here shape/patterns of the data vectors are used as the similarity index for clustering, which overcomes few of the shortcomings associated with distance based clustering approaches. The estimation method used here exploits the pattern identification prowess of the HMM for cluster selection and generalization and nonlinear modeling capabilities of GFM to predict the solar radiation. The data of solar radiation and various meteorological parameters (sun shine hour, ambient temperature, relative humidity, wind speed and atmospheric pressure) to carry out the present work is taken from the comprehensive weather monitoring station made at Solar Energy Centre, Gurgaon, India. To consider the effect of each meteorological parameter on the estimation of solar radiation the proposed model is applied on 15 different sets comprising of various combinations of input meteorological parameters. The meteorological data of three years from 2009 to 2011 (915days) is used to estimate the solar radiation. Out of these 915days data, the first 750days data is used for the training of the proposed paradigm and rest 165days data is used for validating the model. The results of estimation using all the sets of various combination of meteorological parameter are analyzed and it is found that the sunshine duration is the prime parameter for the estimation of solar radiation. The next important parameter, which influences the estimation of solar radiation, is temperature followed by relative humidity, atmospheric pressure and wind speed. It is interesting to note that worse results are obtained for the sets which are not using sunshine duration as an input. The best performance is achieved by the set which uses all the parameters except the wind speed. The Root Mean Square Error (RMSE), Mean Absolute Percentage Error (MAPE) and correlation co-efficient (R-value) of the proposed paradigm for the best performing combination of meteorological parameter are 7.9124, 3.0083 and 0.9921 respectively which shows that the proposed model results are in good agreement with the actual measured solar radiation.
The performance of parabolic trough receiver tubes has a direct impact on concentrated solar power plant production and thus must be maintained at as high a level as possible during the life cycle of ...the plant. In this paper, in-the-field degradation of commercial plant receiver transmittance and absorptance is studied after four years of operation. Since no records of similar measurements were available regarding the reception of the receivers, the results are compared with both the manufacturer's technical specifications and with the guaranteed values. For this purpose, the Mini Incus portable spectrophotometer developed by Abengoa is used to measure the optical properties of an 80-receiver sample. This sample is built up considering the two main factors most likely involved in transmittance and absorptance degradation: interactions with external agents and operating temperature. Therefore, receivers from different locations both in the field and within loops are chosen. A statistical study is performed on the data collected in order to obtain representative values for the whole population of evaluated receivers as well as for every group differentiated. The results reveal no significant degradation of the absorptance or transmittance of the receivers, with measured average transmittance and absorptance values of 96.6 ± 0.2% and 95.9 ± 0.2%, respectively, higher than the 96% and 95% indicated in the technical specification for new first generation receivers. Receiver location in the field and position within the loop does not influence optical property degradation, since the appreciated differences fall within the uncertainty of the measurement device. The obtained results are then compared with the technical specification values and with those guaranteed by the manufacturer after 4 years of operation, and the suitability of the guarantee in matching the reality experienced by the receivers in the field is discussed.
The site-specific evaluation of a solar photovoltaic technology helps in identifying its suitability for that location. The objective of the present study is to assess the suitability of different PV ...technologies under Indian climatic conditions. The performance assessment of photovoltaic technology arrays consisting of polycrystalline silicon, hetero-junction with intrinsic thin layer silicon and amorphous single junction silicon is carried out at a test facility at Solar Energy Centre, in India. The energy yield and performance ratio of each technology, are evaluated. The performance of each technology is also predicted using PV system simulation software and compared with the measured performance. A correction to the module efficiency, results in reducing the absolute percentage error between measured and predicted annual energy yield and performance ratio values to 4.89%, 4.94%, 1.16% and 4.34%, 4.93%, 1.88% for p-Si, HIT and a-Si arrays respectively. The performance comparison shows that HIT and a-Si arrays have performed better than p-Si array at this location. The energy yield of a-Si modules is found to be 14% more in summer months and 6% less in winter months in comparison to p-Si modules. The HIT modules are found to produce 4–12% more energy consistently than p-Si modules.
•Performance of three PV technologies is studied under Indian climatic conditions.•The measured and predicted performance of each technology are also compared•HIT and a-Si modules are found to perform better than p-Si under similar outdoor conditions.•HIT modules are found to produce 4–12% more energy than p-Si modules.•HIT modules are found to perform consistently better than p-Si throughout the year.
Understanding degradation mechanism is of utmost importance for long term reliability of photovoltaic technology. In the present study, degradation analysis of three different photovoltaic technology ...modules namely a-Si (amorphous single junction silicon), HIT (hetro-junction intrinsic thin layer silicon) and m-C-Si (multi-crystalline silicon) is carried out after 28 months of outdoor exposure at Solar Energy Centre, India. A comprehensive test campaign is conducted by visual inspection, thermal imaging and current–voltage characteristic measurements. The soiling of glass is observed in all modules, wavy pattern in back sheet is seen only in a-Si array modules. 50% of m-C-Si modules showed oxidation of silver front grid metallization fingers and antireflective coating at multiple places. Degradation of modules is assessed by measuring characteristic parameters at standard test conditions, before and after outdoor exposure using sun-simulator. The average peak power decay per year is found to be 6.4%, 0.5%, 0.36% in a-Si, m-C-Si and HIT modules respectively. Degradation in each technology array is also calculated analytically and is found to be 5.7 ± 2.5%, 0.51 ± 0.017%, 0.31 ± 0.016% in a-Si, m-C-Si and HIT modules respectively which is in good agreement with experimentally measured results. The study will be useful in further understanding of degradation mechanism under Indian climatic conditions.
•Degradation analysis of a-Si, m-C-Si and HIT PV modules after outdoor exposure is carried out.•Glass soiling, antireflective coating oxidation, wavy pattern on back sheet are the main defects found.•6.4%, 0.5% and 0.36% degradation per year are found in a-Si, m-C-Si and HIT modules respectively.•Results of the study will provide better insight in understanding degradation mechanism.
•Estimation of energy rating of PV module.•Methodology for estimating energy rating based on angle of incidence, spectrum, irradiance, temperature and degradation rate.•Estimation of most frequent ...conditions in terms of occurrence probability for different PV technologies.•Comparison of energy rating for three PV technologies under different climatic conditions.
Energy rating of PV module as per the site-specific climatic condition is essential for customer’s point of view to choose suitable PV technologies. For site and technology-specific energy rating of PV module, it is essential to design standard datasets for it. In this paper, energy ratings of three different technologies with the data sets based on the angle of incidence, spectrum, irradiance, wind and temperature using existing formulae has been reported. The performance surfaces of PV technologies are designed based on the IEC 61853-1 & 2, and IEC 60891. A procedure is reported to including the degradation rate in the energy rating method. Comparisons of energy rating of amorphous silicon, HIT and multi-crystalline silicon using the existing method considering the degradation rate are done with the measured data. It has been observed that all the three technologies at Cold & sunny zone shows the highest energy rating. A procedure, to find out the most frequent conditions in terms of occurrence probability for different PV technologies is also reported.
•Performance analysis of SPV pumps in terms of subsystem efficiency and flow rate.•Detailed analysis of Irradiance and temperature variations on water output.•Performance optimization of pump based ...on water table and operating point.•Effect of different array configurations on the performance of SPV pump using PVsyst.
In this study, effect of irradiance and temperature variations on water output of Solar Photovoltaic (SPV) water pumps has been analyzed. A methodology has been proposed for the performance optimization of SPV pumps based on height of water table and operating point of the pump using most frequent conditions (MFC) of a site. The selection of optimum array sizing for a pump has been done based on the occurrence of desirable input power and subsystem efficiency at MFC. The effect of different array configurations on the performance of water pump using PVsyst software has also been studied. Most of pumps studied, are operating in the average subsystem efficiency range of 40–50%. AC submersible pumps are performing more efficiently and giving higher throughputs at 50m head than DC submersible pump. Around 30m head, 2hp submersible DC pumps are performing better than 2hp submersible AC pumps. AC pumps are showing subsystem efficiency in the range of 28–65% whereas DC pumps efficiency is in the range of 38–60%. For the performance optimization of SPV water pumping systems in real operating conditions, the MFC of radiation and temperature, water table height variations and operating point of a pump can be considered.
•Performance of 3.2 kW CdTe PV system has beem done under the same climatic condition.•EPBT, EPF and LCCE has been done on the basis of annual energy output.•Enviroeconomic analysis has been done on ...the basis of embodied energy and annual energy output.
Life cycle assessment for new emerging photovoltaic (PV) technology is an important tool to establish a PV system in field condition. In this paper, life cycle assessment of the 3.2 kW cadmium telluride (CdTe) PV system has been carried out on the basis of actual field performance data in a composite climate of India. Further, analysis has been performed on the basis of the energy metrics, life cycle assessment, per unit cost of electricity and carbon credit earned. The analysis of the PV system has been performed under the same environmental conditions likely solar irradiation, ambient temperature and wind speed, etc. Energy payback time (EPBT), energy production factor (EPF) and life cycle conversion efficiency (LCCE) of the PV system has been found to be 3.60 years, 0.27 and 0.0018 respectively. The unit cost of electricity of the PV system has been calculated as 9.85 INR/kW h for 5% interest rate and 30 years life span.
•Paper addresses the challenges in the testing of a solar water pumping system.•To confirm whole year pumping, the radiation and temperature profiles are designed.•Testing with Profiles reduce the ...execution time without loss of any attributes.•Developed method takes into consideration of the effects of individual component.
The escalated targets for Solar Photovoltaic water pumping system (SPVWPS) installations in many Asian countries resulted in a huge demand for testing and certification of SPV pump samples. Test laboratories involved in testing and certifications are developing a generalized radiation and temperature profiles to cover various climatic conditions such as hot and dry, hot and humid, composite, cold and cloudy. The present paper addresses the challenges in the testing of a SPVWPS, through a step by step approach and devises solar radiation and temperature profile. Three types of testing profiles are designed to simulate “worst to worst”, “best to best” and “composite” conditions, so that evaluation of the sample can cover all the possibilities of pumping operation for the entire year. One of these three proposed testing profiles, the composite profile, reduces the total time of execution for testing of a sample, without comprising of any attributes of the testing method. Further, the developed composite radiation profile covers the large geographical area of the India and also other Asian countries and yet impart all realistic environmental conditions. The developed method of testing takes into consideration of the effects of individual components such as PV array, solar pump controller and motor pump set individually and collectively. The method also brings out superiorities and shortcomings in these components under the actual field conditions. All relevant experiment results are produced to verify the proposed testing methods.
•Teq and Teff temperatures have been calculated for activation energy 34kJ/mol, 42kJ/mol and 50.1kJ/mol.•Most frequent and harsh condition have also been calculated.•AF has been calculated for ...34kJ/mol, 42kJ/mol and 50.1kJ/mol in indoor/outdoor condition.
Accelerated testing (AT) of the Photovoltaic (PV) module is an important procedure to know the effect of weather under outdoor exposure. The module/cell temperature depends on the environmental parameters such as ambient temperature, global irradiation, wind velocity, type of mounting configuration and type of technology. In this paper, the effect of irradiance, temperature and estimate acceleration factor of Glass, EVA and Tedlar of mono-crystalline silicon (sc-Si) PV modules have been studied to trail the Arrhenius behavior in indoor/outdoor operation for a composite climate at the National Institute of Solar Energy, Gurgaon, India. The irradiance and temperature of the Glass/cell/polymer-sheet and Glass/cell/glass have been calculated using equivalent (Teq) and effective (Teff) temperature. The maximum Teq and Teff temperature is found to be 49.40°C and 54.95°C for the 50.1kJ/mol activation energy for Glass/cell/ polymer sheet. Similarly, 51.2°C and 57.2°C are the maximum values of Teq and Teff are found in Glass/cell/glass for 50.1kJ/mol activation energy. In the present study, 50.1kJ/mol for Glass/cell/polymer sheet configuration required more time to simulate outdoor exposure in comparison to other values of activation energy.
The micromorph thin-film photovoltaic (TFPV) technology uses tandem solar cell structure comprising of hydrogenated amorphous and microcrystalline p-i-n junction silicon cells which needs a long ...period of outdoor exposure for stabilization. In this paper, the performance analysis of grid interactive (GI) micromorph TFPV system has been assessed for a period of 166 days in real operating conditions on the basis of performance ratio (PR), thermal normalized PR (PRSTC), alternate reporting conditions (ARC), energetic and exergetic studies. A novel methodology for performance evaluation has been developed by utilizing per minute operating data collected from a micromorph based GI-TFPV system of 7.92 kWP rated stabilized capacity. The system is found to be operating in the range of 5.1 kWP to 5.6 kWP as compared to the 5.94 kWP stabilized rated capacity after removing the strings with mechanical damaged modules. The average PR and PRSTC of the system are found to be 0.83 and 0.89 respectively, with an average degradation rate of 1.53%/month and 1.22%/month respectively. The average exergetic, energetic and alternate current output efficiencies of the 7.92 kWP GI-TFPV system are found to be 7.38%, 6.83% and 6.69% respectively. The performance of inverters and effect of module breakage has also been evaluated.
•Performance analysis of 7.92 kWP micromorph PV system has been carried out.•Electrical parameters have been assessed at alternative reporting conditions.•Exergy analysis of the system has been carried out.•Average PR and PRSTC of the system are found to be 0.83 and 0.89 respectively.•Average energy and exergy efficiency are found to be 6.91% and 7.48% respectively.
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