Thermal energy storage(TES) systems use solar energy despite its irregular availability and day-night temperature difference.Current work reports the thermal characterizations of solar salt-based phase change composit...Thermal energy storage(TES) systems use solar energy despite its irregular availability and day-night temperature difference.Current work reports the thermal characterizations of solar salt-based phase change composites in the presence of graphene nanoplatelets(GNP).Solar salt(60:40 of NaNO_(3):KNO_(3)) possessing phase transition temperature and melting enthalpy of 221.01℃ and 134.58 kJ/kg is proposed as a phase change material(PCM) for high-temperature solar-based energy storage applications.Thermal conductivity must be improved to make them suitable for widespread applications and to close the gap between the system needs where they are employed.GNP is added at weight concentrations of 0.1%,0.3%,and 0.5% with solar salt using the ball milling method to boost its thermal conductivity.Morphological studies indicated the formation of a uniform surface of GNP on solar salt.FTIR spectrum peaks identified the physical interaction between salt and GNP.Thermal characterization of the composites,such as thermal conductivity,DSC and TGA was carried out for the samples earlier and later 300 thermal cycles.0.5% of GNP has improved the thermal conductivity of salt by 129.67% and after thermal cycling,the enhancement reduced to 125.21% indicating that thermal cycling has a minor impact on thermal conductivity.Phase change temperature decreased by around 2.32% in the presence of0.5% GNP and the latent heat reduced by 4.34% after thermal cycling.TGA thermograms depicted the composites initiated the weight loss at around 550℃ after which it was rapid.After thermal cycling,the weight loss initiated at ~40℃ lower compared to pure salt,which was found to be a minor change.Thermal characterization of solar salt and GNP-based solar salt composites revealed that the composites can be used for enhanced heat transfer in high-temperature solar-based heat transfer and energy storage applications.展开更多
Revise the abstract as follows:This work aims to investigate numerically the influence of the buoyancy ratio and the Dufour parameter on thermosolutal convection in a square Salt Gradient Solar Pond(SGSP).The absorpti...Revise the abstract as follows:This work aims to investigate numerically the influence of the buoyancy ratio and the Dufour parameter on thermosolutal convection in a square Salt Gradient Solar Pond(SGSP).The absorption of solar radiation by the saline water,the heat losses and the wind effects via the SGSP free surface are considered.The mathematical model is based on the Navier-Stokes equations used in synergy with the thermal energy equation.These equations are solved using the finite volume method and the Gauss algorithm.Velocity-pressure coupling is implemented through the SIMPLE algorithm.Simulations of the SGSP are performed for three values of buoyancy ratio(N=1,2 and 10),three values of Dufour parameter(Df?0,0.2 and 0.8)and some sample meteorological data(Tangier,Morocco).Results show that the highest dimensionless temperature of the storage zone is found for N=10.In the same zone and for the same value of N,the dimensionless salt concentration decreases very slightly versus time(unlike for N=1 or 2).Moreover,increasing Df from 0 to 0.8 causes a decrease in the dimensionless temperature of the SGSP storage zone and this decrease is more pronounced for N=1 and N=2.展开更多
The technical feasibility and economy of solar heat collection-forced evaporation process are the keys to its practicality,especially its application in strong brine treatment.The operation cost of applying solar coll...The technical feasibility and economy of solar heat collection-forced evaporation process are the keys to its practicality,especially its application in strong brine treatment.The operation cost of applying solar collection in salt manufacturing through depth evaporation of brine has been studied.For Na^+,K^+,Mg^(2+)//Cl^-,SO_4^(2-)-H_2O salt–water system,most of the Na Cl and all of the Carnallite were separated.The operation cost reached the optimum when the heat collection and evaporation were controlled at 75 and 55°C,respectively.When the solar radiation amount was 19557 kJ·m^(-2)·d^(-1),the solar collector area for producing Carnallite was about 34.27 m^2·(t salt)^(-1),and the operation cost was 13 USD?(t salt)^(-1).The energy consumption of salt manufacturing is at least 25%higher than that of natural evaporation.Regarding the economy,the solar assisted salt manufacturing process is recommended to be performed at a production scale of more than 20 tons per day.展开更多
Introduction The amount of the total dissolved salts(TDS)in most of the salt brines on northern Tibet is relatively lower.So the effective brine concentration technique is needed for lithium,boron and potassium extrac...Introduction The amount of the total dissolved salts(TDS)in most of the salt brines on northern Tibet is relatively lower.So the effective brine concentration technique is needed for lithium,boron and potassium extraction from these展开更多
文摘Thermal energy storage(TES) systems use solar energy despite its irregular availability and day-night temperature difference.Current work reports the thermal characterizations of solar salt-based phase change composites in the presence of graphene nanoplatelets(GNP).Solar salt(60:40 of NaNO_(3):KNO_(3)) possessing phase transition temperature and melting enthalpy of 221.01℃ and 134.58 kJ/kg is proposed as a phase change material(PCM) for high-temperature solar-based energy storage applications.Thermal conductivity must be improved to make them suitable for widespread applications and to close the gap between the system needs where they are employed.GNP is added at weight concentrations of 0.1%,0.3%,and 0.5% with solar salt using the ball milling method to boost its thermal conductivity.Morphological studies indicated the formation of a uniform surface of GNP on solar salt.FTIR spectrum peaks identified the physical interaction between salt and GNP.Thermal characterization of the composites,such as thermal conductivity,DSC and TGA was carried out for the samples earlier and later 300 thermal cycles.0.5% of GNP has improved the thermal conductivity of salt by 129.67% and after thermal cycling,the enhancement reduced to 125.21% indicating that thermal cycling has a minor impact on thermal conductivity.Phase change temperature decreased by around 2.32% in the presence of0.5% GNP and the latent heat reduced by 4.34% after thermal cycling.TGA thermograms depicted the composites initiated the weight loss at around 550℃ after which it was rapid.After thermal cycling,the weight loss initiated at ~40℃ lower compared to pure salt,which was found to be a minor change.Thermal characterization of solar salt and GNP-based solar salt composites revealed that the composites can be used for enhanced heat transfer in high-temperature solar-based heat transfer and energy storage applications.
文摘Revise the abstract as follows:This work aims to investigate numerically the influence of the buoyancy ratio and the Dufour parameter on thermosolutal convection in a square Salt Gradient Solar Pond(SGSP).The absorption of solar radiation by the saline water,the heat losses and the wind effects via the SGSP free surface are considered.The mathematical model is based on the Navier-Stokes equations used in synergy with the thermal energy equation.These equations are solved using the finite volume method and the Gauss algorithm.Velocity-pressure coupling is implemented through the SIMPLE algorithm.Simulations of the SGSP are performed for three values of buoyancy ratio(N=1,2 and 10),three values of Dufour parameter(Df?0,0.2 and 0.8)and some sample meteorological data(Tangier,Morocco).Results show that the highest dimensionless temperature of the storage zone is found for N=10.In the same zone and for the same value of N,the dimensionless salt concentration decreases very slightly versus time(unlike for N=1 or 2).Moreover,increasing Df from 0 to 0.8 causes a decrease in the dimensionless temperature of the SGSP storage zone and this decrease is more pronounced for N=1 and N=2.
基金Supported by the National Natural Science Foundation of China(51674162)the TriJin Scholars and Natural Science Foundation of Shanxi Province(201601D102058)the Provincial Research Projects(2016JD06,2016-HZ-803)
文摘The technical feasibility and economy of solar heat collection-forced evaporation process are the keys to its practicality,especially its application in strong brine treatment.The operation cost of applying solar collection in salt manufacturing through depth evaporation of brine has been studied.For Na^+,K^+,Mg^(2+)//Cl^-,SO_4^(2-)-H_2O salt–water system,most of the Na Cl and all of the Carnallite were separated.The operation cost reached the optimum when the heat collection and evaporation were controlled at 75 and 55°C,respectively.When the solar radiation amount was 19557 kJ·m^(-2)·d^(-1),the solar collector area for producing Carnallite was about 34.27 m^2·(t salt)^(-1),and the operation cost was 13 USD?(t salt)^(-1).The energy consumption of salt manufacturing is at least 25%higher than that of natural evaporation.Regarding the economy,the solar assisted salt manufacturing process is recommended to be performed at a production scale of more than 20 tons per day.
基金Financial support from the opening fund of MLR Key Laboratory of Saline Lake Resources and Environments (2010-SYS-07)China Geological Survey (1212011085523)
文摘Introduction The amount of the total dissolved salts(TDS)in most of the salt brines on northern Tibet is relatively lower.So the effective brine concentration technique is needed for lithium,boron and potassium extraction from these
