The Experts below are selected from a list of 17130 Experts worldwide ranked by ideXlab platform
S Z Xu - One of the best experts on this subject based on the ideXlab platform.
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a zeolite 13x magnesium sulfate water sorption thermal energy storage device for domestic heating
Energy Conversion and Management, 2018Co-Authors: R Z Wang, S Z Xu, Lianyun WangAbstract:A sorption thermal energy storage (TES) device for domestic heating is presented in this article. The TES device adopts the new design scenario with valve-less adsorber and separate reservoir to eliminate the large-diameter vacuum valve for vapor flow, which decreases the cost, reduces the vapor flow resistance, and improves the system reliability. The device is charged by the electric heater, which can add much flexibility to the building energy system as well as contribute to the valley filling and peak shaving from demand side management. The newly developed composite sorbent of zeolite 13X/MgSO4/ENG-TSA (expanded natural graphite treated with sulfuric acid) with the salt mass fraction of 15% in the zeolite 13X/MgSO4 mixture is tested and used in the TES device (denoted as XM15/ENG-TSA). Experimental results show that the TES device with XM15/ENG-TSA has the energy storage density of 120.3kWh∙m−3 at 250°C Charging Temperature and 25–90°C disCharging Temperature. The Temperature lift is as high as 65–69°C with the adsorption and evaporating Temperatures of 25°C. The impregnation of MgSO4 dramatically improves the Temperature rising rate during the adsorption heat recovery process, but the specific energy storage capacity of XM15/ENG-TSA is similar to that of zeolite 13X/ENG-TSA. The effect of the impregnated MgSO4 suggests that MgSO4 can be used for low-Temperature TES to relieve the self-hindrance of the hydration reaction.
Lianyun Wang - One of the best experts on this subject based on the ideXlab platform.
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a zeolite 13x magnesium sulfate water sorption thermal energy storage device for domestic heating
Energy Conversion and Management, 2018Co-Authors: R Z Wang, S Z Xu, Lianyun WangAbstract:A sorption thermal energy storage (TES) device for domestic heating is presented in this article. The TES device adopts the new design scenario with valve-less adsorber and separate reservoir to eliminate the large-diameter vacuum valve for vapor flow, which decreases the cost, reduces the vapor flow resistance, and improves the system reliability. The device is charged by the electric heater, which can add much flexibility to the building energy system as well as contribute to the valley filling and peak shaving from demand side management. The newly developed composite sorbent of zeolite 13X/MgSO4/ENG-TSA (expanded natural graphite treated with sulfuric acid) with the salt mass fraction of 15% in the zeolite 13X/MgSO4 mixture is tested and used in the TES device (denoted as XM15/ENG-TSA). Experimental results show that the TES device with XM15/ENG-TSA has the energy storage density of 120.3kWh∙m−3 at 250°C Charging Temperature and 25–90°C disCharging Temperature. The Temperature lift is as high as 65–69°C with the adsorption and evaporating Temperatures of 25°C. The impregnation of MgSO4 dramatically improves the Temperature rising rate during the adsorption heat recovery process, but the specific energy storage capacity of XM15/ENG-TSA is similar to that of zeolite 13X/ENG-TSA. The effect of the impregnated MgSO4 suggests that MgSO4 can be used for low-Temperature TES to relieve the self-hindrance of the hydration reaction.
Sandip K. Saha - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of latent heat thermal energy storage using encapsulated phase change material for solar thermal power plant
Renewable Energy, 2016Co-Authors: Kunal Bhagat, Sandip K. SahaAbstract:Thermal energy storage improves the load stability and efficiency of solar thermal power plants by reducing fluctuations and intermittency inherent to solar radiation. This paper presents a numerical study on the transient response of packed bed latent heat thermal energy storage system in removing fluctuations in the heat transfer fluid (HTF) Temperature during the Charging and disCharging period. The packed bed consisting of spherical shaped encapsulated phase change materials (PCMs) is integrated in an organic Rankine cycle-based solar thermal power plant for electricity generation. A comprehensive numerical model is developed using flow equations for HTF and two-Temperature non-equilibrium energy equation for heat transfer, coupled with enthalpy method to account for phase change in PCM. Systematic parametric studies are performed to understand the effect of mass flow rate, inlet Charging system, storage system dimension and encapsulation of the shell diameter on the dynamic behaviour of the storage system. The overall effectiveness and transient Temperature difference in HTF Temperature in a cycle are computed for different geometrical and operational parameters to evaluate the system performance. It is found that the ability of the latent heat thermal energy storage system to store and release energy is significantly improved by increasing mass flow rate and inlet Charging Temperature. The transient variation in the HTF Temperature can be effectively reduced by decreasing porosity.
Ashmore Mawire - One of the best experts on this subject based on the ideXlab platform.
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investigation of in 48sn as a phase change material candidate for thermal storage applications
Renewable Energy and Environmental Sustainability, 2017Co-Authors: Ashmore Mawire, Adedamola ShoboAbstract:Latent heat storage systems provide large thermal storage densities for solar energy storage for various domestic and industrial applications. In–48Sn, an alloy of indium and tin a lead-free solder is investigated as a phase change material (PCM) in latent heat storage systems for heating applications. Results obtained from differential scanning calorimetry indicate that the alloy is useful in storing sensible heat beyond its melting Temperature as it exhibits very little decomposition up to 400 °C. Though In–48Sn possesses a low latent heat of fusion, its high density allows for a larger thermal storage mass. The behaviour of In–48Sn in a 50 mm aluminium spherical capsule during Charging and disCharging cycles is investigated using sunflower oil as the heat transfer fluid (HTF) at flow rates of 3, 6, 9 and 12 ml/s. The influence of the Charging Temperature on the Charging characteristics of the encapsulated PCM is also investigated. The average Charging and disCharging rates of the encapsulated PCM show an increase with an increase in the HTF flow rate. The HTF Temperature determines the maximum Temperature attained by the PCM and thus the total energy stored by the encapsulated PCM. In–48Sn shows good potential as a PCM in a spherical aluminium capsule for packed bed domestic heat storage systems.
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simulated energy and exergy analyses of the Charging of an oil pebble bed thermal energy storage system for a solar cooker
Solar Energy Materials and Solar Cells, 2008Co-Authors: Ashmore Mawire, M Mcpherson, R R J Van Den HeetkampAbstract:Abstract Energy balance equations are used to model the solar energy capture (SEC) system and the thermal energy storage (TES) system of a proposed indirect solar cooker. An oil–pebble bed is used as the TES material. Energy and exergy analyses are carried out using two different Charging methods to predict the performance of the TES system. The first method charges the TES system at a constant flowrate. In the second method, the flowrate is made variable to maintain a constant Charging Temperature. A Simulink block model is developed to solve the energy balance equations and to perform energy and exergy analyses. Simulation results using the two methods indicate a greater degree of thermal stratification and energy stored when using constant-Temperature Charging than when using constant-flowrate Charging. There are greater initial energy and exergy rates for the constant-flowrate method when the solar radiation is low. Energy efficiencies using both methods are comparable whilst the constant-Temperature method results in greater exergy efficiency at higher levels of the solar radiation. Parametric results showing the effect of each Charging method on the energy and exergy efficiencies are also presented.
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experimental characterisation of a thermal energy storage system using Temperature and power controlled Charging
Renewable Energy, 2008Co-Authors: Ashmore Mawire, Michael McphersonAbstract:The experimental set-up and technical aspects for Charging a thermal energy storage (TES) of a proposed solar cooker at constant Temperature and variable electrical power are presented. The TES is developed using a packed pebble bed. An electrical hot plate simulates the concentrator which heats up oil circulating through a copper coil absorber Charging the TES system. A computer program to acquire data for monitoring the storage system and to maintain a nearly constant outlet Charging Temperature is developed using Visual Basic. The input power to the hot plate is also controlled to simulate the variation of the daily solar radiation by using another Visual Basic program. A combined internal model control (IMC) and proportional, integral and derivative (PID) Temperature control structure is tested on the TES system under varying conditions and its performance is reasonable within a few degrees of the set Temperature points. Results of the Charging experiments are used to characterise the storage system. The different experiments indicate various degrees of stratification in the storage tank.
R Z Wang - One of the best experts on this subject based on the ideXlab platform.
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high energy density multi form thermochemical energy storage based on multi step sorption processes
Energy, 2019Co-Authors: J X Xu, T X Li, Jingwei Chao, R Z WangAbstract:Abstract A novel multi-form thermochemical energy storage method is proposed for high energy-density thermal energy storage based on multi-step sorption processes. The proposed multi-form thermochemical energy storage combines the physisorption energy storage of a porous matrix, the chemisorption energy storage of a salt hydrate, and the absorption energy storage of the salt solution. High-performance composite sorbent of MgCl2@zeolite was prepared to demonstrate the feasibility of the proposed multi-form thermochemical energy storage. The water uptake contributions of physisorption, chemisorption and absorption of the composite sorbent were measured by a “three-step” hydration method. The multi-step desorption processes measured by TG at an extremely slow heating rate shows the apparent decrease of decomposition Temperature of MgCl2 hydrates in zeolite matrix. The maximum sorption capacity of the MgCl2@zeolite composite sorbent without solution leakage is as high as 0.55 g/g and its gravimetric and volumetric thermal energy densities reach 1368 kJ/kg and 308 kWh/m3 respectively with Charging Temperature of 200 °C. This gravimetric energy density is about 2.26 times higher than that of pure zeolite 13X. The experimental results verified that the proposed multi-form thermochemical energy storage is an effective method to improve sorption capacity and to achieve high energy-density thermal storage.
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a zeolite 13x magnesium sulfate water sorption thermal energy storage device for domestic heating
Energy Conversion and Management, 2018Co-Authors: R Z Wang, S Z Xu, Lianyun WangAbstract:A sorption thermal energy storage (TES) device for domestic heating is presented in this article. The TES device adopts the new design scenario with valve-less adsorber and separate reservoir to eliminate the large-diameter vacuum valve for vapor flow, which decreases the cost, reduces the vapor flow resistance, and improves the system reliability. The device is charged by the electric heater, which can add much flexibility to the building energy system as well as contribute to the valley filling and peak shaving from demand side management. The newly developed composite sorbent of zeolite 13X/MgSO4/ENG-TSA (expanded natural graphite treated with sulfuric acid) with the salt mass fraction of 15% in the zeolite 13X/MgSO4 mixture is tested and used in the TES device (denoted as XM15/ENG-TSA). Experimental results show that the TES device with XM15/ENG-TSA has the energy storage density of 120.3kWh∙m−3 at 250°C Charging Temperature and 25–90°C disCharging Temperature. The Temperature lift is as high as 65–69°C with the adsorption and evaporating Temperatures of 25°C. The impregnation of MgSO4 dramatically improves the Temperature rising rate during the adsorption heat recovery process, but the specific energy storage capacity of XM15/ENG-TSA is similar to that of zeolite 13X/ENG-TSA. The effect of the impregnated MgSO4 suggests that MgSO4 can be used for low-Temperature TES to relieve the self-hindrance of the hydration reaction.
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thermochemical characterizations of high stable activated alumina licl composites with multistage sorption process for thermal storage
Energy, 2018Co-Authors: Yongwei Zhang, R Z WangAbstract:Abstract High-stable activated alumina/LiCl composites with multistage sorption process were fabricated to store low-Temperature heat below 120 °C. The worried issue of solution leakage was solved by controlling its salt content below the threshold value. The microstructure was observed by transmission electron microscopy (TEM). Research on nitrogen adsorption suggested that because of the impregnated salt, composite sorbents presented different pore structure from pure activated alumina. Based on the measured results of water isotherms, the sorption equilibrium states represented by the mass concentration of the inside LiCl solution were evaluated. Moreover, the multistage sorption process-physical adsorption, chemical adsorption and liquid-gas solution absorption were quantitative analyzed based on the capillary condensation mechanism and hydrous reaction equation. Sorption kinetics proved that the sorption capacity of composite sorbents was significantly improved compared with pure activated alumina. Sorption energy storage density was obtained by the TGA/DSC measurement. Overall, AA/LiCl composite sorbent with salt content of 14.68% was selected as the optimistic AA/LiCl composite sorbent with a sorption capacity of 0.45 g/cm3 (0.41 g/g) and an energy storage density of 318.3 kWh/m3 (1041.5 kJ/kg) at the condition of 20 °C, 80% RH with a Charging Temperature of 120 °C.