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[IEEE 2018 4th International Conference on Renewable Energies for Developing Countries (REDEC) - Beirut, Lebanon (2018.11.1-2018.11.2)] 2018 4th International Conference on Renewable Energies for Developing Countries (REDEC) - Phase Change Materials in a Domestic Solar Hot Water Storage Tank of the Lebanese Market
摘要： The availability of some kinds of renewable energy resources is un-continuous, for example the solar collectors can only produce heat when the sun is shining. Thermal Energy Storage (TES) is crucial to match between the intermittent solar heat supply and the heat demand. In this paper, a Phase Change Material (PCM) is integrated in the Domestic Solar Hot Water Storage Tank (DSHWST) as a Latent Heat Storage (LHT). Based on the application requirements in Lebanon, a suitable PCM is selected. While this PCM solidifies, it releases its heat and keeps the water inside the DSHWST warmer than 55 oC along 10 hours. The needed mass of PCM was calculated and two types of containers were investigated: the tubes and the spheres. As well as, the comparison between DSHWST integrated with PCM (DSHWST-PCM) and the Conventional Domestic Solar Hot Water Storage Tank (CDSHWST) is introduced, in order to examine the performance of PCM heating against that with an Electrical Resistance (ER). Features are expressed in terms of system payback and CO2 emission. Due to the issue of electrical power availability in Lebanon, the PCM integrated in The DSHWST has the following two advantages: yearly, reducing the primary electricity power by about 6.5 MWh and get rid of about 5.5 tons of CO2.
关键词： Thermal Energy Storage,Phase Change Material,Hot Water Storage Tank,Lebanon
更新于2025-09-23 15:22:29
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[IEEE 2018 2nd IEEE Conference on Energy Internet and Energy System Integration (EI2) - Beijing, China (2018.10.20-2018.10.22)] 2018 2nd IEEE Conference on Energy Internet and Energy System Integration (EI2) - Concentrating Solar Power Station Optimal Operation Model
摘要： With the improvement of energy structure, large scale grid connection of renewable energy, as a new technology for absorbing solar energy, concentrating solar power generation uses a thermal storage system to make it a schedulable resource without increasing the uncertainty of the system. This paper considers the energy transfer process and the thermal energy conversion efficiency among the concentrating solar modules, and constructs their basic operation models respectively. Through the design of different operating modes, the examples are simulated. The values of key parameters are taken into account to optimize the operation results. The impact of the analysis shows that concentrating solar power plants have certain advantages in dealing with solar energy uncertainty, prolonging production cycles, improving the utilization efficiency of heat storage tanks, and economic efficiency.
关键词： Concentrating solar power,renewable energy,thermal energy storage,optimal operation
更新于2025-09-23 15:22:29
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Annual performance analysis and optimization of a solar tower aided coal-fired power plant
摘要： The integration of solar energy into coal-fired power plants has been proven as a potential approach in the utilization of solar energy to reduce coal consumption. Moreover, solar augmentation offers low cost and low risk alternatives to stand-alone solar thermal power plants. In this study, the annual performance of a solar tower aided coal-fired power (STACP) system is investigated, and the influence of thermal storage system capacity on the annual solar generating power and annual solar-to-electricity efficiency is explored. The thermal storage system capacity is optimized to obtain the lowest levelized cost of electricity (LCOE). At the same time, the influence and sensitivity of several important economic factors are explored and assessed. Results demonstrate that compared to a coal-fired power system, the reduction in the annual average coal consumption rate of the STACP system with high direct normal irradiance (DNI), medium DNI, and low DNI are 5.79, 4.52, and 3.22 g/kWh, respectively. At a minimum, the annual coal consumption can be reduced by 14,000 t in a 600 MWe power generation unit. Because the same solar field is considered under different DNI conditions, the LCOE in the high DNI, medium DNI, and low DNI scenarios are all fairly similar (6.37, 6.40, and 6.41 ￠/kWh, respectively). When the solar multiple is 3.0, the optimal thermal storage capacity of the STACP system, with high, medium, and low DNIs are 6.73, 4.42, and 2.21 h, respectively. The sensitivity analysis shows that the change in economic parameters exerts more influence on the STACP system with the high DNI compared with the other two scenarios.
关键词： Thermal energy storage capacity,Solar multiple,Annual performance,Optimization,Solar tower aided coal-fired power plant
更新于2025-09-23 15:22:29
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A Novel Multi-objective Dynamic Programming Optimization Method: Performance Management of a Solar Thermal Power Plant as a Case Study
摘要： Due to the intermittent nature of solar irradiance, solar power plants are usually equipped with energy storage systems. Suitable charge and discharge management of the storage systems can considerably help increase the reliability and profitability of the solar systems. In this regard, various optimization approaches, with their own strengths and limitations, have been employed by literature. Dynamic Programming (DP) is one of the fittest approaches for the wide range of engineering problems which exhibit the properties of overlapping sub-problems. DP is a simple, gradient-free, efficient, and deterministic optimization method that guarantees the optimal solution. However, this method has not been developed for multi-objective problems. This study develops a multi-objective DP method and employs it for the performance management of a solar power plant equipped with thermal energy storage system. “Daily electricity generation” and “daily revenue obtained from selling electricity” are considered to be the objective functions. The superiority of the developed method is shown through a comparison with one of the most commonly used multi-objective optimization approaches, NSGA-II. This comparison indicates that the multi-objective DP attains 3.0%- 7.5% greater values of electricity generation and 3.1%-12.6% higher values of revenue than NSGA-II, for the different levels of solar radiation.
关键词： Thermal Energy Storage System,Optimal Performance,Solar Thermal Power Plant,Multi-objective Dynamic Programming method
更新于2025-09-23 15:21:21
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[Energy, Environment, and Sustainability] Advances in Solar Energy Research || Techno-Economic Potential of Large-Scale Solar Deployment in the US
摘要： PV system generates electricity with minimum environmental impact reduces than conventional greenhouse gas emission and consequently reduces the effects of global warming. In late of 2014, the Indian government announced an ambitious target of 100 GW installation capacity of solar PV systems by 2022. Since then, India has achieved notable progress towards this goal and has installed 20 GW cumulative solar capacity with 9.6 GW in 2017 alone. Based on the 2015 MIT Energy Initiative, by 2050, a major fraction of the world’s electric power will come from solar sources. However, this poses many technical and economic challenges on the electrical infrastructure. In this chapter, we focus on the US case, by studying the technical and economic potentials of large-scale deployment of the most commonly recognized types of solar; photovoltiac (PV) and concentrated solar power (CSP) at different locations in the US. The technical potential is assessed based on grid interconnection topologies, and solar system performance. The economic potential is evaluated based on several metrics such as the levelized avoided cost of energy (LACE) and levelized cost of electricity (LCOE), and the possibility of integration into the electricity markets. The economic potential also covers the subsidies, taxes, policies, and incentives for large-scale solar deployment. Two simulation case studies are implemented on two large-scale solar PV and CSP projects at different locations in the US to evaluate their techno-economic potentials.
关键词： Concentrated solar power,Heat transfer fluid,NPV,LCOE,Thermal energy storage,Photovoltaic system,LACE,Payback period,Mounting system
更新于2025-09-23 15:21:21
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Thermodynamic efficiency comparison between thermal and electric storage for photovoltaic-driven chilling system
摘要： Faced with the ever-increasing pressures from climate change and environmental pollution, stand-alone photovoltaic (PV) power generation is promising in providing electricity to the air conditioners. However, the solar energy is usually susceptible to the weather changes, making the power supply unreliable. To mitigate the e?ects caused by the solar intermittency, additional energy storage bu?er is necessary. In this paper, stand-alone PV chilling systems with water tank thermal energy storage (TES) and battery electric energy storage (EES) strategies are quantitatively compared by evaluating the thermodynamic e?ciency, respectively. A chiller model is ?rstly built, based on which the initial steady states are derived. Secondly, the EES and TES system models are built based on the compressor speed control strategy and refrigeration cycle model. The resulting chilled water temperature ?uctuation curves in TES and EES PV chillers are subsequently obtained. Quantitative comparative results in this paper are threefold. i) The average chilled water temperature of the TES strategy is 11.08% lower than that in the EES strategy; ii) The average cooling energy amount stored in the TES strategy is 43.6% larger than that in the EES strategy, indicating that the chilled water tank has a better energy storage potential in the given PV chiller system; iii) The water volume of TES is optimized to derive the maximum cooling energy storage rate which is 76.92% larger than that in the EES system.
关键词： Chilling system,Thermal energy storage,Electrical energy storage,Solar energy
更新于2025-09-23 15:19:57
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Risk assessment in a central concentrating solar power plant
摘要： In this paper, optimal scheduling of a central concentrating solar power (CSP) plant which is one of the most promising technologies in the solar energy is investigated in the presence of different uncertainties. Thermal energy storage is integrated with the CSP plant in order to allow the plant to be independent from the instantaneous solar radiation. In order to model different uncertainty such as power market price and solar irradiation, a new hybrid information gap decision theory (IGDT)-stochastic method is introduced which is a mixed-integer linear programming method and presents more reliable results in a suitable computation time. In the proposed method the uncertainty of the solar irradiation is modeled by IGDT method while power market price uncertainty is considered by a set of fifty scenarios. Three different strategies as risk-averse, risk-neutral and risk-taker are introduced to analyze the operation of the CSP plant. In the risk-neutral strategy, obtained profit is equal to $3895 which is reduced in the risk-averse strategy by increasing robustness value indicating increased uncertainty of the solar irradiation. In the risk-taker strategy, the CSP operating profit will be equal to $4245 by 15% of increase in solar radiation, comparing with the risk-neutral case shows almost 8.2% increase in profit.
关键词： Information gap decision theory (IGDT),Solar thermal energy storage,Stochastic optimization,Concentrating solar power (CSP) plant
更新于2025-09-19 17:15:36
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Amino-Functionalized Single-Walled Carbon Nanotubes-Integrated Polyurethane Phase Change Composites with Superior Photothermal Conversion Efficiency and Thermal Conductivity
摘要： The development of organic phase change materials (PCMs) with good shape stability, superior photothermal conversion efficiency, and high thermal conductivity is critical for practical photothermal utilizations. Herein, novel form-stable solar-thermal conversion and storage materials (SPCMs) with superior photothermal conversion efficiency and thermal conductivity were successfully synthesized by introducing amino-functionalized single-walled carbon nanotubes (SWNTs?NH2) into poly(ethylene glycol)-based polyurethane PCM. Differential scanning calorimetry (DSC) and thermal conductivity test results showed the SPCMs possessed relatively high phase change enthalpies in the range of 124.0?126.1 J/g and that the introduction of SWNTs?NH2 effectively enhanced the thermal conductivities of SPCMs. Sunlight irradiation experiments showed that the introduction of SWNTs?NH2 into PEG-based polyurethane PCM significantly improved the solar-thermal conversion and storage efficiency of SPCMs from 44.8% to 89.3%. The light irradiation cycling tests and thermogravimetric (TG) analyses indicated that the SPCMs exhibit satisfactory reversible stability and thermal stability. Moreover, SPCMs with SWNTs?NH2 added exhibited much higher solar-thermal conversion and storage efficiency and better reversible stability than SPCM with SWNTs added. In conclusion, the synthesized SPCMs show considerable potential for solar-thermal conversion and storage applications.
关键词： Poly(ethylene glycol),Solar-thermal conversion,Thermal energy storage,Single-walled carbon nanotubes,Phase change materials
更新于2025-09-19 17:13:59
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Thermal modelling of a flat plate solar collector with latent heat storage validated with experimental data in outdoor conditions
摘要： This paper presents a thermal modelling strategy to evaluate the performance of latent heat storage technique in a ?at plate solar collector (FPSC) with integrated phase change material (PCM). A thermal dynamic model is developed based in simpli?ed semi empirical correlations and includes heat transfer by conduction, convection and radiation in each part of the device. Melting process of the PCM is described with energy balances for a set of discrete spatial layers to calculate temperature and liquid fraction. The model is validated with experimental data gathered under outdoor conditions from a real ?at plate solar collector prototype modi?ed to incorporate PCM containers between the absorber plate and the insulation. As result of the validation process, the model shows the capability to estimate the global thermal performance of the device with good accuracy compared with the experimental measurements and using minimal computational resources. Comparisons between estimations of the model and test data are presented for 20 days, real conditions include days with both high and low incident radiation and two di?erent PCMs. Predicted temperature of glass cover, absorber plate, water outlet and PCM are obtained with a maximum error of 4.62%. The model was employed to analyze the collector thermal performance. Temperatures, heat transfer, stored energy of collector main components and liquid fraction of PCM are estimated and analyzed in two cases: under clear sky condition without strong changes of solar radiation and under scattered weather with solar radiation variation. Two PCMs with di?erent melting points (45 °C and 60 °C) are analyzed and compared with results without PCM by using the model to evaluate their performance.
关键词： Flat plate solar collector,Thermal energy storage,Thermal model,Experimental validation,PCM
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Numerical study of a two pass shell and tube latent heat energy storage system
摘要： The thermal behaviour of PCM in different configuration of heat exchangers is analysed for the purpose of design and optimisation of a latent heat thermal energy storage unit. Numerical modelling in conjunction with scale analyses provides a cost effective means to examine the performance of different configurations of latent heat storage systems. The main objective of this work is to scale down an experimental set up to a numerical model which can represent the thermal behaviour of the system with reasonable computational time. A U-tube element from a shell and tube thermal storage experimental set up was used as the model for a numerical study, using FLUENT. The predicted results of the temperature profiles in the PCM domain are in agreement with the measured data. Moreover, the heat transfer fluid outlet temperature and duration of the phase change processes are consistent with experimental results. Using the experimental initial temperature at each point in comparison to using an average initial temperature from all points can improve the predicted temperature profiles. Furthermore, three different mushy zone constants; namely 105, 107, 108 were used to examine the impact on the rate of melting. It was found that the constant 107 provides a closer solution to the experimental results. Results of this study show that the small scale model can represent the lab scale set up, providing more detail about the thermal behaviour of the PCM which is difficult to capture by measurement. The model can also be used for further examination of a high temperature PCM within the same set up for a CSP application.
关键词： FLUENT,shell and tube,numerical modelling,PCM,latent heat thermal energy storage
更新于2025-09-10 09:29:36