Muhammad Sumair, Tauseef Aized, M. A. Bhutta, Layba Tehreem, Muhammad Shoaib
The objective of this work is to develop empirical correlations describing Diffuse Fraction (DF) as a function of (1) Sunshine Fraction (SF), (2) Clearness Index (CI) and (3) both SF and CI. Four years instantaneously measured data was changed to monthly data at five locations belonging to five different climatic regions in Pakistan which was used as training dataset and nine correlations for each location (a total of forty-five) were formulated and their performance was assessed. Moreover, nine general empirical models were developed using the entire dataset (11 years) for five locations which were termed as Generalized Correlations (GCs). These GCs were validated by applying them to five other locations and comparing the generated results with measured results for those locations (validation dataset). The best model among GCs were found as GC8 which was, then applied to compute DF for five more locations for which short term (8 months) measured data was also available and thus a reasonable comparison could be made. Results showed that (1) new models were better than literature models, (2) GCs correlations were found in good agreement and (3) 2nd degree multivariate polynomial models are the best performance models with minimum errors e.g. Mean Absolute Biased Error (MABE), Mean Absolute Percentage Error (MAPE), Root Mean Square Error (RMSE), Sum of Square of Relative Error (SSRE) and Standard Relative Error (SRE) for GC8 were estimated as 0.018, 6.397, 0.021, 0.006 and 0.022 respectively (all values for Karachi).
{"title":"Performance Evaluation of Newly Developed Generalized Correlations for the Prediction of Solar Diffuse Fraction for Various Climatic Regions","authors":"Muhammad Sumair, Tauseef Aized, M. A. Bhutta, Layba Tehreem, Muhammad Shoaib","doi":"10.1115/1.4055102","DOIUrl":"https://doi.org/10.1115/1.4055102","url":null,"abstract":"\u0000 The objective of this work is to develop empirical correlations describing Diffuse Fraction (DF) as a function of (1) Sunshine Fraction (SF), (2) Clearness Index (CI) and (3) both SF and CI. Four years instantaneously measured data was changed to monthly data at five locations belonging to five different climatic regions in Pakistan which was used as training dataset and nine correlations for each location (a total of forty-five) were formulated and their performance was assessed. Moreover, nine general empirical models were developed using the entire dataset (11 years) for five locations which were termed as Generalized Correlations (GCs). These GCs were validated by applying them to five other locations and comparing the generated results with measured results for those locations (validation dataset). The best model among GCs were found as GC8 which was, then applied to compute DF for five more locations for which short term (8 months) measured data was also available and thus a reasonable comparison could be made. Results showed that (1) new models were better than literature models, (2) GCs correlations were found in good agreement and (3) 2nd degree multivariate polynomial models are the best performance models with minimum errors e.g. Mean Absolute Biased Error (MABE), Mean Absolute Percentage Error (MAPE), Root Mean Square Error (RMSE), Sum of Square of Relative Error (SSRE) and Standard Relative Error (SRE) for GC8 were estimated as 0.018, 6.397, 0.021, 0.006 and 0.022 respectively (all values for Karachi).","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48871036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arivazhagan Sampathkumar, Subbarama Kousik Suraparaju, S. Natarajan
The main objective of this study is to enhance the yield of single slope solar still by extending the operating time of solar still by utilizing composite heat storage materials in the solar still. In this regard, the effect of the composite heat energy storage material developed by the mixture of beach sand with paraffin wax is investigated. The experiments are carried out in Solar Still with Composite Heat Storage Material (SSCHSM), and results are compared with Solar Still with Sensible Heat Storage Material (SSSHSM), Solar Still with Latent Heat Storage Material (SSLHSM), and Conventional Solar Still (CSS). The outcome of the two days' results showed that the total yield of SSCHSM, SSLHSM, SSSHSM, and CSS are 2050, 1880, 1420, and 1250 mL/m2 respectively on day 1 whereas on day 2 it is 2950, 2680, 2000, and 1820 mL/m2. The thermal analysis results indicated that the average thermal efficacy of SSCHSM, SSLHSM, SSSHSM, and CSS is 21.59,19.83,14.92, and 13.16 %, respectively, on day one and day two it is 27.42,24.94, 18.59, and 16.89 %. The economic analysis revealed that the cost per liter and payback month of SSCHSM is 0.031 and 6.2 months, whereas the cost per liter for SSLHSM, SSSHSM, and CSS was 0.034, 0.044, and 0.048, respectively. Moreover, the payback period for SSLHSM, SSSHSM, and CSS was 6.8 months, 8.8 months, and 9.7 months, respectively.
{"title":"Enhancement of Yield in Single Slope Solar Still by Composite Heat Storage Material – Experimental and Thermo-Economic Assessment","authors":"Arivazhagan Sampathkumar, Subbarama Kousik Suraparaju, S. Natarajan","doi":"10.1115/1.4055100","DOIUrl":"https://doi.org/10.1115/1.4055100","url":null,"abstract":"\u0000 The main objective of this study is to enhance the yield of single slope solar still by extending the operating time of solar still by utilizing composite heat storage materials in the solar still. In this regard, the effect of the composite heat energy storage material developed by the mixture of beach sand with paraffin wax is investigated. The experiments are carried out in Solar Still with Composite Heat Storage Material (SSCHSM), and results are compared with Solar Still with Sensible Heat Storage Material (SSSHSM), Solar Still with Latent Heat Storage Material (SSLHSM), and Conventional Solar Still (CSS). The outcome of the two days' results showed that the total yield of SSCHSM, SSLHSM, SSSHSM, and CSS are 2050, 1880, 1420, and 1250 mL/m2 respectively on day 1 whereas on day 2 it is 2950, 2680, 2000, and 1820 mL/m2. The thermal analysis results indicated that the average thermal efficacy of SSCHSM, SSLHSM, SSSHSM, and CSS is 21.59,19.83,14.92, and 13.16 %, respectively, on day one and day two it is 27.42,24.94, 18.59, and 16.89 %. The economic analysis revealed that the cost per liter and payback month of SSCHSM is 0.031 and 6.2 months, whereas the cost per liter for SSLHSM, SSSHSM, and CSS was 0.034, 0.044, and 0.048, respectively. Moreover, the payback period for SSLHSM, SSSHSM, and CSS was 6.8 months, 8.8 months, and 9.7 months, respectively.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48351639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In a sensible storage system, energy is stored based on the distribution of energy and exergy at the specified conditions. It is believed that the least temperature gradient leads to a higher exergy availability and lower entropy generation in a storage system. An energy storage unit with multiple passages fitted with wire coil inserts is evaluated in the present work by assessing the exergy stored and the entropy generation number for HTF inlet temperature range of 45 to 75 °C and HTF flow rate of 0.022 to 0.029 kg/s. The wire coil inserts have (p/d) ratio in the range of 0.25-0.75. The maximum exergy storage rate in the energy storage unit is found to be 55.43 W corresponding to an energy storage unit having wire coil insert (p/d=0.25) at the HTF inlet temperature of 75 °C and HTF flow rate of 0.029 kg/s. Entropy generation number of the system with wire coil inserts (p/d= 0.5), compared to smooth HTF passage and is found to be 42.32% at HTF flow rate and inlet temperature of 0.026 kg /s and 45 °C, respectively.
{"title":"Exergetic performance analysis of energy storage unit fitted with wire coil inserts","authors":"Ravi Kumar, M. Kumar, A. Patil","doi":"10.1115/1.4055074","DOIUrl":"https://doi.org/10.1115/1.4055074","url":null,"abstract":"\u0000 In a sensible storage system, energy is stored based on the distribution of energy and exergy at the specified conditions. It is believed that the least temperature gradient leads to a higher exergy availability and lower entropy generation in a storage system. An energy storage unit with multiple passages fitted with wire coil inserts is evaluated in the present work by assessing the exergy stored and the entropy generation number for HTF inlet temperature range of 45 to 75 °C and HTF flow rate of 0.022 to 0.029 kg/s. The wire coil inserts have (p/d) ratio in the range of 0.25-0.75. The maximum exergy storage rate in the energy storage unit is found to be 55.43 W corresponding to an energy storage unit having wire coil insert (p/d=0.25) at the HTF inlet temperature of 75 °C and HTF flow rate of 0.029 kg/s. Entropy generation number of the system with wire coil inserts (p/d= 0.5), compared to smooth HTF passage and is found to be 42.32% at HTF flow rate and inlet temperature of 0.026 kg /s and 45 °C, respectively.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42489382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The generation of wind fields is of interest in the study of the structural performance of wind turbines in critical events, such as thunderstorm downbursts. Various methods ranging from the use of empirical data to employing computational simulations are typically adopted to study the response of wind turbines in downburst flow fields. While the former approach is limited in the ability to account for accurate and spatially resolved details of the flow field, the latter is expensive and therefore, has limitations in its use. As an alternative, in this work, we propose a Paused Downburst Model in which a snapshot of a time-dependent computational fluid dynamics (CFD) simulation is used to generate mean wind fields during thunderstorm downbursts. The developed model for the mean wind field is validated against recorded downburst data in the literature. The turbulent component of the wind field is generated using computationally inexpensive techniques based on Fourier-based power spectral density functions and coherence functions. In an illustrative example, the combined mean and turbulence wind fields are generated and applied on a utility-scale wind turbine to study structural load characteristics during a downburst event.
{"title":"A computational model to simulate thunderstorm downbursts for wind turbine loads analysis","authors":"Phanisri P. Pratapa, Hieu H. Nguyen, L. Manuel","doi":"10.1115/1.4055076","DOIUrl":"https://doi.org/10.1115/1.4055076","url":null,"abstract":"\u0000 The generation of wind fields is of interest in the study of the structural performance of wind turbines in critical events, such as thunderstorm downbursts. Various methods ranging from the use of empirical data to employing computational simulations are typically adopted to study the response of wind turbines in downburst flow fields. While the former approach is limited in the ability to account for accurate and spatially resolved details of the flow field, the latter is expensive and therefore, has limitations in its use. As an alternative, in this work, we propose a Paused Downburst Model in which a snapshot of a time-dependent computational fluid dynamics (CFD) simulation is used to generate mean wind fields during thunderstorm downbursts. The developed model for the mean wind field is validated against recorded downburst data in the literature. The turbulent component of the wind field is generated using computationally inexpensive techniques based on Fourier-based power spectral density functions and coherence functions. In an illustrative example, the combined mean and turbulence wind fields are generated and applied on a utility-scale wind turbine to study structural load characteristics during a downburst event.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44988798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermal model is developed to predict the outlet water temperature with respect to time for water-in-tube type evacuated solar collector connected in series. Developed mathematical expression is validated for the single collector and two collectors connected in series. In each collector, there are 20 evacuated tubes connected to the storage tank. Coefficient of Determination (R2), Reduced Chi-Square (χ2), and Root Mean Squared Error (RMSE) have been calculated to show the prediction accuracy of the developed model. For single and two collectors connected in series, R2 is 99.73% and 99.90%, χ2 is 0.46°C and 0.39°C and RMSE is 0.70°C and 0.65°C, respectively. Predicted value shows good agreement with the experimental value. At a constant mass flow rate, the maximum outlet temperature reaches 53.10°C and 71.50°C for single and two collectors in series, respectively. The maximum energy for the single collector is 4.12 kW and 4 kW, while for two collectors connected in series, the maximum energy is 7.08 kW and 6.69 kW. Average thermal efficiency is 4.45% and 4.51% and average exergy efficiency is 9.66% and 15.17% for single and series-connected collectors, respectively. Developed model can design energy-efficient ‘water-in-tube type evacuated tube collector’ for domestic and industrial applications.
{"title":"Thermal Modeling of Water-in-Tube Type Evacuated Tube Solar Collectors to Predict Outlet Water Temperature: An Experimental Validation","authors":"Pushpendra Singh, M. Gaur, G. Tiwari, Ashok Kumar","doi":"10.1115/1.4055075","DOIUrl":"https://doi.org/10.1115/1.4055075","url":null,"abstract":"\u0000 Thermal model is developed to predict the outlet water temperature with respect to time for water-in-tube type evacuated solar collector connected in series. Developed mathematical expression is validated for the single collector and two collectors connected in series. In each collector, there are 20 evacuated tubes connected to the storage tank. Coefficient of Determination (R2), Reduced Chi-Square (χ2), and Root Mean Squared Error (RMSE) have been calculated to show the prediction accuracy of the developed model. For single and two collectors connected in series, R2 is 99.73% and 99.90%, χ2 is 0.46°C and 0.39°C and RMSE is 0.70°C and 0.65°C, respectively. Predicted value shows good agreement with the experimental value. At a constant mass flow rate, the maximum outlet temperature reaches 53.10°C and 71.50°C for single and two collectors in series, respectively. The maximum energy for the single collector is 4.12 kW and 4 kW, while for two collectors connected in series, the maximum energy is 7.08 kW and 6.69 kW. Average thermal efficiency is 4.45% and 4.51% and average exergy efficiency is 9.66% and 15.17% for single and series-connected collectors, respectively. Developed model can design energy-efficient ‘water-in-tube type evacuated tube collector’ for domestic and industrial applications.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46312862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Assaad Alsahlani, K. Randhir, Michael Hayes, Philipp Schimmels, Nesrin Ozalp, J. Klausner
Solar fuels are proven to be promising candidates for thermochemical energy storage. However, the transient nature of solar radiation is an obstacle to maintaining a stable operational temperature inside a solar reactor. To overcome this challenge, the temperature of a solar reactor can be regulated by controlling the incoming solar radiation or the feedstock flowrate inside the reactor. In this work, a combined Proportional-Integral- Derivative (PID) controller is implemented to regulate the temperature inside a high-temperature tubular solar reactor with counter-current flowing gas/particles. The control model incorporates two control systems to regulate incoming solar radiation and gas flow simultaneously. The design of the controller is based on a reduced-order numerical model of a high-temperature tubular solar reactor that is vertically oriented with an upward gas flow and downward particle flow. The reactor receives heat circumferentially through its wall over a finite segment of its length. Formulation of the heat transfer model is presented by applying the energy balance for the reactor tube and considering heat and mass transfer inside. A set of governing differential equations are solved numerically by using finite volume method to obtain reactor wall, particles, and gas temperatures along the reactor length with various boundary conditions. Simulation results are used to tune the PID controller parameters by utilizing the Ziegler–Nichols tuning method. Both the simulation results and the controller performance are visualized on the LabVIEW platform. The controller is challenged to track different temperature setpoints with different scenarios of transient solar radiation. The performance of the PID controller was compared to experimental results obtained from industrial PID controller embedded to 7 kW electric furnace. Results shows that the combined PID controller is successful in maintaining a stable temperature inside the reactor by regulating the incoming solar radiation and the flowrate via small steady-state error and reasonable settling time and overshoot.
{"title":"DESIGN OF A COMBINED PID CONTROLLER TO REGULATE THE TEMPERATURE INSIDE A HIGH-TEMPERATURE TUBULAR SOLAR REACTOR","authors":"Assaad Alsahlani, K. Randhir, Michael Hayes, Philipp Schimmels, Nesrin Ozalp, J. Klausner","doi":"10.1115/1.4055296","DOIUrl":"https://doi.org/10.1115/1.4055296","url":null,"abstract":"\u0000 Solar fuels are proven to be promising candidates for thermochemical energy storage. However, the transient nature of solar radiation is an obstacle to maintaining a stable operational temperature inside a solar reactor. To overcome this challenge, the temperature of a solar reactor can be regulated by controlling the incoming solar radiation or the feedstock flowrate inside the reactor. In this work, a combined Proportional-Integral- Derivative (PID) controller is implemented to regulate the temperature inside a high-temperature tubular solar reactor with counter-current flowing gas/particles. The control model incorporates two control systems to regulate incoming solar radiation and gas flow simultaneously. The design of the controller is based on a reduced-order numerical model of a high-temperature tubular solar reactor that is vertically oriented with an upward gas flow and downward particle flow. The reactor receives heat circumferentially through its wall over a finite segment of its length. Formulation of the heat transfer model is presented by applying the energy balance for the reactor tube and considering heat and mass transfer inside. A set of governing differential equations are solved numerically by using finite volume method to obtain reactor wall, particles, and gas temperatures along the reactor length with various boundary conditions. Simulation results are used to tune the PID controller parameters by utilizing the Ziegler–Nichols tuning method. Both the simulation results and the controller performance are visualized on the LabVIEW platform. The controller is challenged to track different temperature setpoints with different scenarios of transient solar radiation. The performance of the PID controller was compared to experimental results obtained from industrial PID controller embedded to 7 kW electric furnace. Results shows that the combined PID controller is successful in maintaining a stable temperature inside the reactor by regulating the incoming solar radiation and the flowrate via small steady-state error and reasonable settling time and overshoot.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45038485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Rodrigues, P. Torres, M. Galhardo, Otávio A. Chase, Alan Amorim, Wesley Leão, W. Macêdo
This paper applies different methodologies through measurement and simulation for the partial shading analysis of SPV arrays. A two-diode photovoltaic solar cell model evaluates SPV arrays under shading conditions. Experimental data from two identical 1.5 kWp PV generators was used as a study case. One is subjected to shading caused by the branches of a tree, resulting in its electricity production being affected for several days, and the other is shadow-free. The authors use a methodology based on short-circuit of the solar cells to determine the different irradiance levels. It was considered because it avoids using several irradiance sensors to map the shaded and unshaded regions in a shadow SPV array. The two-diode photovoltaic solar cell model used was developed in MATLAB/Simulink. The applied model and the map irradiance methodology can be used to represent IV curves in complex shading. For example, what could help identify if a given SPV array is working on a Global Maximum Power Point or a Local Maximum Power Point. Furthermore, the experimental results demonstrated that the model and methodology are useful in understanding what happens with SPV arrays in very complex shadow situations.
{"title":"Theoretical-experimental evaluation of partially shaded solar photovoltaic arrays through methodological framework: a case study involving two identical 1.5 kWp PV generators.","authors":"M. Rodrigues, P. Torres, M. Galhardo, Otávio A. Chase, Alan Amorim, Wesley Leão, W. Macêdo","doi":"10.1115/1.4054922","DOIUrl":"https://doi.org/10.1115/1.4054922","url":null,"abstract":"\u0000 This paper applies different methodologies through measurement and simulation for the partial shading analysis of SPV arrays. A two-diode photovoltaic solar cell model evaluates SPV arrays under shading conditions. Experimental data from two identical 1.5 kWp PV generators was used as a study case. One is subjected to shading caused by the branches of a tree, resulting in its electricity production being affected for several days, and the other is shadow-free. The authors use a methodology based on short-circuit of the solar cells to determine the different irradiance levels. It was considered because it avoids using several irradiance sensors to map the shaded and unshaded regions in a shadow SPV array. The two-diode photovoltaic solar cell model used was developed in MATLAB/Simulink. The applied model and the map irradiance methodology can be used to represent IV curves in complex shading. For example, what could help identify if a given SPV array is working on a Global Maximum Power Point or a Local Maximum Power Point. Furthermore, the experimental results demonstrated that the model and methodology are useful in understanding what happens with SPV arrays in very complex shadow situations.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42244499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rachid Lekhal, Mohand Ameziane Ait Ali, T. Ahmed Zaid
This work presents a numerical simulation of a thermal model for a solar loop with parabolic trough collectors (PTC) considering fluid recirculation at closed-loop operation during sunrise. At the beginning of the day, the heat transfer fluid is recirculated in a closed-loop in order to obtain the inlet loop operating temperature without resorting to additional preheating energy. Energy balances are carried out on the heat transfer fluid (HTF), the absorber tube and the glass envelope as a function of optical and thermo-physical parameters of the heat collector element (HCE). A system of second-order differential equations was established and mathematical model resolved by finite difference and Newton-Raphson methods for solution. This model has been well validated by comparing the results with existing experimental and numerical data. Three typical days of winter, spring and summer were simulated for the solar loop operation considering a closed-loop (CL) fluid recirculation at start-up conditions. Results show a more flexible closed-loop operation at relatively large flow rates compared to the open-loop (OL) operation, which requires substantial preheating energy at the same conditions; the start-up solar field using a closed loop recirculation allows us both operational autonomy and significant energy savings. Solar loop thermal and optical powers gained and lost are plotted for the typical days considered; we observe that maximum thermal efficiency of 66.53 % is achieved at 2.27 p.m. for the summer day.
{"title":"Thermal model of a parabolic trough solar field with a closed-loop operation during sunrise period","authors":"Rachid Lekhal, Mohand Ameziane Ait Ali, T. Ahmed Zaid","doi":"10.1115/1.4054919","DOIUrl":"https://doi.org/10.1115/1.4054919","url":null,"abstract":"\u0000 This work presents a numerical simulation of a thermal model for a solar loop with parabolic trough collectors (PTC) considering fluid recirculation at closed-loop operation during sunrise. At the beginning of the day, the heat transfer fluid is recirculated in a closed-loop in order to obtain the inlet loop operating temperature without resorting to additional preheating energy. Energy balances are carried out on the heat transfer fluid (HTF), the absorber tube and the glass envelope as a function of optical and thermo-physical parameters of the heat collector element (HCE). A system of second-order differential equations was established and mathematical model resolved by finite difference and Newton-Raphson methods for solution. This model has been well validated by comparing the results with existing experimental and numerical data. Three typical days of winter, spring and summer were simulated for the solar loop operation considering a closed-loop (CL) fluid recirculation at start-up conditions. Results show a more flexible closed-loop operation at relatively large flow rates compared to the open-loop (OL) operation, which requires substantial preheating energy at the same conditions; the start-up solar field using a closed loop recirculation allows us both operational autonomy and significant energy savings. Solar loop thermal and optical powers gained and lost are plotted for the typical days considered; we observe that maximum thermal efficiency of 66.53 % is achieved at 2.27 p.m. for the summer day.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43462526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Arosh, Kuntal Ghosh, D. K. Dheer, Surya Prakash
Incidence of Non-uniform illumination degrades the affected solar photovoltaic modules temporarily. However, in worst case it may also lead to permanent degradation. Thus, non-uniform illumination sensing in terms of encompassed area over solar photovoltaic module become important for sustainable power generation. In this work, we propose, an integrated framework by combining optical and thermal images for Non-uniform illumination sensing and classification (static and dynamic). The proposed technique detects hotspots along with identification of the nature of shading on the solar photovoltaic modules. Additionally, Hungarian Kalman Filter is implemented for estimating the coverage of the Non-uniform illumination-affected region including its abrupt shape. The proposed estimation technique also calculates the total loss in the output energy of the solar photovoltaic system due to non-uniform illumination. Overall, the proposed methodology develops a hybrid imagery-dependent advanced early warning system for large-scale solar power plants that are cost-effective and bypass multi-sensor data fusion to attain real-time application.
{"title":"Composite imagery-based non-uniform illumination sensing for system health monitoring of solar power plants","authors":"S. Arosh, Kuntal Ghosh, D. K. Dheer, Surya Prakash","doi":"10.1115/1.4054921","DOIUrl":"https://doi.org/10.1115/1.4054921","url":null,"abstract":"\u0000 Incidence of Non-uniform illumination degrades the affected solar photovoltaic modules temporarily. However, in worst case it may also lead to permanent degradation. Thus, non-uniform illumination sensing in terms of encompassed area over solar photovoltaic module become important for sustainable power generation. In this work, we propose, an integrated framework by combining optical and thermal images for Non-uniform illumination sensing and classification (static and dynamic). The proposed technique detects hotspots along with identification of the nature of shading on the solar photovoltaic modules. Additionally, Hungarian Kalman Filter is implemented for estimating the coverage of the Non-uniform illumination-affected region including its abrupt shape. The proposed estimation technique also calculates the total loss in the output energy of the solar photovoltaic system due to non-uniform illumination. Overall, the proposed methodology develops a hybrid imagery-dependent advanced early warning system for large-scale solar power plants that are cost-effective and bypass multi-sensor data fusion to attain real-time application.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48549330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solar technologies are an efficient means of addressing environmental pollution and climate change challenges. In this study, an organic Rankine cycle (ORC) system driven by solar evacuated glass tubes named solar water power generation system (SWPG) was experimentally investigated to explore the performance of the SWPG system in powering buildings. For ORC, a new mixture called TD-3 was introduced for the experiment after comparing the thermodynamic characteristics of five working fluids using REFPROP software. The solar radiation intensity was simulated for solar collectors to determine the best installation angle of the evacuated glass tubes to be 30° in Tianjin, China. The power generating efficiency was tested as high as 4.5% at 1:00 pm on July 15. The optimization of operating parameters and the modification of generating equipment contributed to the increase in power generation. The SWPG system could achieve an optimal power output when the system guaranteed a small superheat and no more than 3°C subcooling using the TD-3. The transmission ratio between the generator and expander also impacted power generation that the ratio of 2:1 helped optimize the power generation.
{"title":"An exploration of the application to buildings of an organic Rankine cycle power generation system driven by solar evacuated glass tubes","authors":"Ying Sheng, W. Han, Zhang He","doi":"10.1115/1.4054920","DOIUrl":"https://doi.org/10.1115/1.4054920","url":null,"abstract":"\u0000 Solar technologies are an efficient means of addressing environmental pollution and climate change challenges. In this study, an organic Rankine cycle (ORC) system driven by solar evacuated glass tubes named solar water power generation system (SWPG) was experimentally investigated to explore the performance of the SWPG system in powering buildings. For ORC, a new mixture called TD-3 was introduced for the experiment after comparing the thermodynamic characteristics of five working fluids using REFPROP software. The solar radiation intensity was simulated for solar collectors to determine the best installation angle of the evacuated glass tubes to be 30° in Tianjin, China. The power generating efficiency was tested as high as 4.5% at 1:00 pm on July 15. The optimization of operating parameters and the modification of generating equipment contributed to the increase in power generation. The SWPG system could achieve an optimal power output when the system guaranteed a small superheat and no more than 3°C subcooling using the TD-3. The transmission ratio between the generator and expander also impacted power generation that the ratio of 2:1 helped optimize the power generation.","PeriodicalId":17124,"journal":{"name":"Journal of Solar Energy Engineering-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49165763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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