Performance Of Tank Research Articles

Simulation of a composite latent heat storage tank with horizontal baffles and two phase-change temperatures

A composite latent heat storage tank (CLHST) is fabricated using baffles and two phase-change materials (PCMs) with different phase-change temperatures. The performance of the tank is optimized based on both structure and material. This optimization approach is a new integrated method differing from those developed in previous studies, where only a single aspect of the structure/material is considered. Experimental verification and simulation analysis are used to analyze the difference between the integrated and single-structure/material optimization methods and their influence on the thermal properties of the traditional latent heat storage tank (TLHST). The results show that the CLHST exhibits the best characteristics. Compared with the TLHST, the CLHST’s charging quantity increases by 13.6%, the outlet temperature can be increased by 6.5°C, and the utilization rate of PCM exceeds 85%. Moreover, the PCM in the CLHST melts more completely than unilaterally adding baffles. The charging and discharging quantities of the CLHST increase by more than 10% than just using two PCMs. Furthermore, adding baffles can increase the charging quantity by 11% compared to using two PCMs. Evidently, the tank design must be improved considering several aspects, and structural optimization plays a more important role in improving tank performance.

Integrating biokinetics with computational fluid dynamics for energy performance analysis in anaerobic digestion

Anaerobic digestion (AD) is an effective process for decomposing organic matter in wastewater treatment plants (WWTPs) where highly efficient digesters properly mix the sludge. To ensure a uniform substance distribution, a comprehensive modeling method is necessary. Computational fluid dynamics (CFD) helps in the modeling of AD tanks but few studies have focused on integrating hydrodynamics with biokinetics because of complex AD processes. The current study presents a new CFD platform for estimating the biokinetics of WWTPs to assess the energy performance of AD tanks. The presented method is validated by numerical and experimental studies, and facilitates a link between methane production and mixing energy consumption. The on-site settings of the recirculation mixing system in the studied WWTP was able to prepare a uniform mixture of the material. However, reducing mixing rate to decrease energy consumption did not lead to proper mixing quality.

The Confinement Effect on the Buckling Performance of Cylindrical Tanks

The Confinement Effect on the Buckling Performance of Cylindrical Tanks

Investigation and optimization on melting performance of a triplex-tube heat storage tank by rotational mechanism

Phase change heat storage is the backbone of energy storage technology, but its storage time is affected by the low thermal conductivity of phase change materials. Therefore, the melting performance of a triplex-tube latent heat thermal energy storage unit (T-LHTESU) in a phase change heat storage system is studied in this paper, and the rotation mechanism is applied to the unit. Firstly, a numerical model of the T-LHTESU considering the rotation mechanism is constructed, and the validity of the rotation unit is verified by comparison with experimental data. In this unit, N-eicosane is used as a phase change material for heat exchange. The effects of different rotational speeds on the liquid phase distribution, temperature distribution, flow velocity distribution, total energy storage, and energy storage efficiency of the T-LHTESU are studied. The results show that the melting time of this unit at 0.1 and 1 rpm is 46.98 and 69.35% lower than that of the stationary model, respectively. The total amount of stored heat is decreased by 0.67 and 2.17%, and the heat storage efficiency is increased by 87.34% and 219.19%, respectively. This indicates that the addition of the rotation mechanism greatly increases the heat storage efficiency of the T-LHTESU and reduces its total melting time, while the reduction of the total energy stored in the melting cycle is small. Then it is proved that rotation improves the single heat transfer mechanism of the stationary model and eliminates the thermal deposition caused by natural convection by studying the internal temperature/velocity response of the stationary model and the speed of 0.1 rpm. The related geometric structure of the model is optimized by response surface optimization design based on 0.1 rpm rotation speed. The influence of each variable on the target response is obtained, and compared with the original model, the melting time of the optimized model is reduced by 12.24%. Finally, based on the geometric optimization design, the influence of element physical factors (temperature and material of fin/tube wall) on the related melting properties is studied. This study is helpful to promote the effective use of rotation mechanism in phase change heat storage systems and has a certain guiding role in the structural design.

Numerical investigation on performance enhancement of metal-hydride hydrogen tank using electromagnetic induction heating

Due to their large volumetric storage capacity for hydrogen at safe, moderate temperatures and pressures, metal hydrides have received much attention by researchers. Since one of the major controlling factors of the storage process is heat transfer from/to the metal hydride bed, several methods to improving heat transfer have been published. In the present work, electromagnetic induction is investigated numerically as a new heating method to enhance the performance of metal-hydride hydrogen tanks. A two-dimensional mathematical model that describes the dynamic behavior of a LaNi5 hydrogen tank encircled by a copper coil crossed by an alternating current was developped and successfully validated with experimental data. Numerous numerical simulations are performed using this model, and the results reveal that electromagnetic induction can shorten the hydrogen tank's discharging time by 87 % when compared to the heat transfer fluid approach. Furthermore, by raising the desorption temperature from 303 K to 353 K, the discharging time may be reduced by 73 %. The rapidity of the discharging process is unaffected significantly by raising the desorption temperature above 353 K, though. For desorption pressures lower than 0.1 bar, the same effect was observed. Studying the impact of the coil's number of turns per unit length revealed that by increasing this parameter from 640 to 3200, the discharging time is considerably reduced. Nevertheless, increasing this number above 3200 has a negligible impact on the metal-hydride hydrogen tank's dynamic behavior.

An Experimental Investigation on the Performance of a Water Storage Tank with Sodium Acetate Trihydrate

Phase change material (PCM) water tanks have a major influence on the efficiency improvement of solar energy systems. This article discusses the effects of PCM under various inlets in a tank based on related research. So as to research the performance of the water storage tank, this paper built a set of water tank experimental systems using sodium acetate trihydrate. The thermal characteristics of two different water tanks were analyzed at 2, 6 and 10 L/min when the inlet temperature was 20 °C and the initial high temperature was 80 °C. The test results indicate that adding PCMs helps to provide an extra 1.4% of stored heat, prolong the hot water outlet time, and has a better thermal stratification, compared with ordinary water tanks. However, PCMs do not give off heat quickly at high flow rates. Besides the exergy efficiency (EE) gradually decreasing, the MIX number first decreases and then increases; the fill efficiency (FE) has the opposite trend with the flow increasing. FE has a max of 0.905 at 6 L/min.

An optimization study on the performance of hot water tank integrated phase change material

In this paper, a new structure of a phase change thermal storage tank is proposed with the aim of enhancing the thermal storage capacity of the domestic hot water tank without occupying the water storage volume. The structure of the proposed tank is that the phase change material is filled in the outer side wall of the tank and the cavity formed by an insulation layer, which does not occupy the water storage space inside the tank. The cavity is equipped with metal spacers in parallel with each other as a method to strengthen heat transfer. The effects of three structural design parameters, namely the thickness of phase change material, the number and thickness of spacers on the charging and discharging process were investigated by the means of numerical calculations. A numerical model was developed by using COMSOL Multiphysics, and the accuracy of the model was verified with experimental data from the literature. The average temperature of phase change material, average water temperature, and liquid/solid phase fraction were used to evaluate the thermal performance of the phase change thermal storage tank.It was found that the low thermal conductivity of the phase change material affected the thermal performance. When the thickness of the phase change material was 30 mm, the discharging time was prolonged by 10 %, which was 5 h longer than the common water tank. The installation of metal spacers was an effective method to enhance heat transfer. During the charging process, the phase change material had a stronger liquefaction trend, and the lowest value of the solid fraction was 0.25. During the discharging process, when the number of spacers was 17 and the thickness was 5 mm, the discharging time was extended to 80 h, which was 1.5 times of the common water tank. The results help to understand the optimized design parameters of the phase change thermal storage tank from the perspective of the structural design.

Effect of phase change material tubes inclination angel on the performance of indirect hybrid thermal energy storage system: An experimental approach

• A modular indirect hybrid thermal energy storage tank is designed and investigated. • Temperature evolution of the PCM and the water in the tank are studied. • Thermal performance of the water tanks with and without PCM tubes are compared. • Effect of the PCM tubes inclination angel on the thermal performance is discussed. For an efficient use of indirect hybrid thermal energy storage, it is necessary to investigate the heat transfer characteristics of its charging and discharging processes. However, in previous studies, the inclination angel of phase change material (PCM) units is fixed. The influence of PCM units inclination angel on the thermal performance of the indirect hybrid thermal energy storage has not attracted much attention. To address this research gap, this study proposes a modular indirect hybrid thermal energy storage tank in which the PCM tubes inclination angel can be changed freely. The heat transfer characteristics of the tanks with horizontal, inclined, vertical PCM tubes, and without PCM tubes are studied by experiments. The experimental results show that the melting time of horizontal PCM tube is the shortest, which is 25% less than that of vertical PCM tube. However, the solidification time for all the three different inclination angel tubes is the same at 96 min. Compared to the tank without PCM tubes, the average overall heat transfer coefficient of the heat exchanger during charging/discharging processes for the tanks with PCM tubes are increased by 7.18%/7.58% (horizontal), 1.37%/10.05% (inclined), and 4.43%/8.96% (vertical), respectively. The maximum average thermal storage rate of 1.31 kW is observed in the tank with horizontal PCM tubes, which is an increase of 5.65% compared with the tank without PCM tubes. For the discharging process, the difference of the average thermal release rate among the four tanks is not noticeable. The results indicate that the PCM tubes inclination angel has significant impacts on the melting time of PCM, the heat transfer coefficient of the heat exchanger and average thermal storage rate of the tank. Optimizing the PCM tubes inclination angel is an effective way to improve the thermal storage rate of the indirect hybrid thermal energy storage system.

Experimental-numerical study on ballistic impact behavior of 316L austenitic stainless steel plates against blunt and ogival projectiles

316L austenitic stainless steel (ASS) is the standard reference material in fabricating pressurized hydrogen storage tanks due to its low hydrogen embrittlement sensitivity and excellent corrosion resistance. Ballistic performance of such tanks is of course a concern of safety. In this study, ballistic impact behavior of 316L ASS was studied against blunt and ogival nose shaped projectiles within impact velocity range of 160.3–324.1 m/s. Ballistic impact behavior of 316L ASS is sensitive to nose shapes of projectiles. For targets against blunt projectile, shear plugging with ejected plugs is observed, and target deflection is limited; for targets against ogival projectile, failure mode is ductile hole enlargement, small bulge and some fragments are observed on front and rear sides of targets, respectively. Ballistic limit velocities (BLVs) for two projectiles are respectively 180.9 m/s and 333.5 m/s, indicating better energy absorption against ogival projectile. Numerical simulations of ballistic impact tests were carried out using either the Lode independent MJC or the Lode dependent modified Mohr-Coulomb (MMC) fracture criterion. Numerical prediction by the latter is more accurate than the former as ballistic impact tests are dominated by stress state where Lode parameter is strong enough to cause a big difference between MMC and MJC criteria, and fracture behavior is accurately predicted by the latter but overestimated by the former.

Social and Institutional Factors Influencing the Performance of Tank Irrigation System – A Study of Uthiramerur Tank in the Indian State of Tamil Nadu

Aim: Tanks were the major sources of irrigation for agriculture and storehouses of economic, social, aesthetic and environmental use values. However, in the present context, the current trends are showing that area and number of tanks are being reduced due to poor maintenance, encroachments, degradation of catchment area and siltation, etc. This calls for rehabilitation and rejuvenation of the existing tank irrigation systems so as to preserve this precious natural resource for the livelihood of future generations ahead. Hence this present study was undertaken to identify the social and institutional factors influencing the performance of tank systems in Kanchipuram district in the Indian state of Tamil Nadu.
 Study Design: Quota and Multistage random sampling method was followed.
 Place and Duration of Study: Command and Non-command areas of the Uthiramerur Tank in Kanchipuram district of Tamil Nadu during 2020-2021.
 Methodology: A Sample size of 120 sample respondents from the different locations of the command areas (Head, Middle, Tail and Non-command area) of Uthiramerur tank were selected and interviewed.
 Results: It was observed from the performance analysis that over the years the tank’s performance was decreasing both in terms of filled in capacity vis-à-vis rainfall received (Above the tank outlet) and in terms of actual gross area irrigated vis-à-vis its potential command area (Below the tank outlet) . One of the important reasons for the decline in the performance of Uthiramerur tank was attributed mainly to institutional deficiencies wherein concrete action lacked thereof.
 Conclusion: The study suggested the following actions for the improvement of tank’s performance- streamlining the feeding channels of the tank by removing the encroachments, lining of channels to minimize the seepage losses and ensuring better water distribution, periodic desiltation ,strengthening the revenue collection mechanisms, encouraging the conjunctive water use and rejuvenating the water user association.

Numerical study on stratification performance of cascaded three-layered packed-bed in the thermal storage process

Packed-bed thermal storage tank (PBTST) has broad application prospects in solar water heating systems, thermoelectric decoupling in power plants, and industrial waste heat recovery. In the present work, a three-dimensional PBTST model with three-stage phase change material (PCM) and three-layered diameter capsules was proposed, its thermal energy storage behavior and thermal stratification performance were studied by numerical simulation. The effects of PCM bed height ratio, fluid flow rate, and inlet temperature on the stratification performance of the new tank were investigated. The results reported that due to the increased heat transfer area and expanded heat-transfer temperature difference: (1) Compared with the conventional non-cascaded single-layered diameter capsule PBTST, the charging efficiency of the cascaded three-layered diameter capsule PBTST increased from 24% to 61% at the end of charging; (2) the cascaded three-layered diameter capsule PBTST shows significantly improved stratification properties compared to the conventional ones, with the Richardson number increased from 20.78 to 49.47; (3) increasing the height of the bottom PCM bed, raising the inlet temperature, and reducing the flow rate all can improve the stratification performance.

Study on thermal storage performance of heat storage tank with phase change material balls

In order to promote the application of heat storage device using phase change material (PCM), a water tank filled with sodium acetate trihydrate ball was designed, and its performance was studied. The effects of inlet temperature, flow rate on the charging and discharging time, hot water supply, thermal storage efficiency of PCM tank were analyzed through experiments and simulations. A new concept “heat loss rate of the heat exchange blind area” was put forward, by which the impact of PCM ball position on the heat exchange blind area was analyzed. The results show that with the increase of inlet temperature and flow rate, the charging and discharging time decrease. The hot water supply and the thermal storage efficiency reaches their maximum value (28.3L/h, 78 %) at the flow rate of 25L/h and the inlet temperature of 80 °C. When the height of the bracket in PCM tank is 60 mm, the heat loss rate of heat exchange blind area decreases by 47 %. The best height of PCM balls is 90 mm, which increases the average temperature of heat exchange blind area by 1.8 %. The study has guided significance for the practical application of water tank with phase change thermal storage module.

Effects of Different Heat Transfer Conditions on the Hydrogen Desorption Performance of a Metal Hydride Hydrogen Storage Tank

To investigate the influence of thermal effects on the hydrogen desorption performance of the metal hydride hydrogen storage system, a two-dimensional numerical model was established based on a small metal hydride hydrogen storage tank, and its accuracy was verified by the temperature variations in the reaction zone of the hydrogen storage tank during hydrogen desorption. In addition, the influence of the heat transfer medium on the heat and mass transfer performance of the hydrogen desorption reaction was analyzed. An external heat transfer bath was added to simulate the thermal effect of the model during the hydrogen desorption reaction. The temperature and type of heat transfer medium in the heat transfer bath were modified, and the temperature and reaction fraction variations in each zone of the hydrogen storage model were analyzed. The results showed that under heat transfer water flow, the reaction rate in the center region of the hydrogen storage tank was gradually lower than that in the wall region. The higher the temperature of water flow, the shorter the total time required for the hydrogen desorption reaction and the shortening amplitude is reduced. The variations in the temperature and hydrogen storage capacity during hydrogen desorption were similar, with water and oil as the heat transfer medium, under the same flow rate and heat transfer temperature, however, the heat transfer time and hydrogen desorption time of water were about 10% and 5% shorter than that of oil, respectively. When the air was used as the heat transfer medium, the heat transfer rate of the air convection in the channel was lower than the heat transfer rate of the tank wall, reducing the temperature difference between the air and alloy on both sides of the wall, decreasing heat transfer efficiency, and significantly prolonging the time required for hydrogen desorption.

Performance improvement of adsorptive hydrogen storage on activated carbon: Effects of phase change material and inconstant mass flow rate

Due to the multiple advantages of activated carbon (e.g. high specific surface area, safety and low cost) toward hydrogen storage, the subject of heat management in H2-storage tanks has become a research focus in recent years. In this work, using a computational fluid dynamics (CFD) model (implemented in Fluent software), the performance of a hydrogen storage tank (packed with activated carbon) was analyzed in the presence of PCM/oil-based thermal recovery/release systems. The charging, dormancy, and discharging cycles of the storage tank were investigated with respect to the variation of the injected mass flow rate of hydrogen (from 2 × 10−4 to 8 × 10−4 kg/s). There was good agreement between our findings and those obtained from the experiment. It was observed that the adsorption capacity of the solid bed is proportionally enhanced with the rise in the mass flow rate of hydrogen. In addition, independently of the used hydrogen mass flow rate, it has been observed that the charging periods were ended at the same instant (i.e. t = 400 s). According to the enthalpy contours and liquid fraction of PCM (~18 and 30 % at 400 and 4000 s, respectively), it has been concluded that the thermal conductivities of the adopted PCM and that of solid bed (activated carbon) should be enhanced for better performance of the hydrogen stocking tank. Finally, from a viewpoint of storage performance and process cost, it is therefore possible to realize rapid charging/discharging of the activated carbon tank with adopting a PCM and oil-based thermal unit for heat management.

Feasibility analyses of negative-stiffness dampers for seismic performance enhancement of a base-isolated liquid storage tank

Base-isolation systems are widely used to reduce the hydrodynamic base shear and overturning moment of liquid storage tanks with increased isolator displacements and liquid sloshing responses. Supplementing conventional damping devices in the isolation layer can effectively reduce isolator displacements whereas having limited influence on the liquid sloshing. In the present paper, simultaneous reduction on the isolator displacement and sloshing response of a base-isolated liquid storage tank is achieved by using negative-stiffness dampers (NSDs). NSDs consisting of a negative-stiffness component coupled in parallel with a fluid viscous damping component are considered, and an equivalent linearization technique is proposed for designing their properties on the basis of the principle of equal average energy dissipation. A four-lumped-mass model considering high sloshing modes of liquid storage tank is used as a numerical example. The feasibility of NSDs for improving the seismic performance of base-isolated storage tanks with varying aspect ratios is verified. Moreover, nonlinear response history analyses are conducted to illustrate the benefits of the proposed method for the seismic protection of base-isolated storage tanks. The seismic responses of base-isolated storage tanks controlled by using the proposed and traditional methods are comprehensively compared, and it is suggested that the proposed method can be advantageous over conventional ones by more effectively reducing base shear and sloshing responses without compromising isolator displacements.

Performance of the polyurea-coated steel tank under air blast load: a numerical study

Performance of the polyurea-coated steel tank under air blast load: a numerical study

Charging and discharging processes of low capacity nano-PCM based cool thermal energy storage system: An experimental study

The present study aims to investigate the performance of the low-capacity energy storage tank in different heat transfer fluid (HTF) conditions (at various flow rates) filled with spherical capsules containing nano-enhanced phase change material (nano-PCM). The nano-PCM is prepared by dispersing functionalized graphene nanoplatelets (f-GNP) with deionized (DI) water. The influence of HTF inlet temperature and volumetric flow rates on the total charging and discharging time of an energy storage tank filled with 35 spherical capsules are analyzed. The maximum reduction in total charging and discharging time of 18.26% and 22.81% is recorded for different HTF conditions. The amount of latent heat energy stored is nearly 5.5 times higher than the sensible heat stored at the HTF temperature of −4 °C. The cumulative energy recovery of 2637 kJ is recorded during the discharging process, which is 85.89% of the actual energy stored (3070 kJ) in the storage tank. In addition, the dispersion of f-GNP reduces the specific energy consumption (SEC) by around 28% for the nano-PCM at −4 °C HTF temperature. It is found that the required output temperature and average melting rate can be achieved in practical applications through the control of the flow rate of HTF and its inlet temperature.

Geometry optimisation of an industrial thermocline Thermal Energy Storage combining exergy, Life Cycle Assessment and Life Cycle Cost Analysis

Recently, packed-bed storage has been considered as a promising alternative solution for thermal energy storage especially for waste heat recovery in industrial plants. This work aims to optimise environmental footprint, costs and exergy efficiency of a thermocline thermal energy storage through two optimisation variables. These variables describe the tank shape and the particle grain size. Two solid filler materials are compared: machined ceramic and ceramic from fly ashes. The reference storage is an existing industrial high-temperature air/bauxite packed-bed storage called Eco-Stock®. A one-dimensional two-phase (fluid and solid) model is used to determine the energy and exergy performance of the thermocline tank. For the life cycle assessment, four indicators are selected: cumulative energy demand, global warming potential, abiotic depletion potential and particulate matter. Finally, a life cycle cost analysis is performed to determine levelised cost of energy used as economic criterion. This multi-objective problem is solved by the multi-criteria genetic algorithm available on the Matlab® platform. A Pareto set is obtained, bounded by the single exergy and environmental optimisation solutions. The economic optimisation is found on the Pareto set, close to the environmental optimal solution. Favouring economic performance reduces the environmental footprint of the storage. Despite better exergy performance and smaller tank volume, the exergy-optimised tank increases environmental impacts and costs due to higher pumping work. The environmental and economic optimisations lead to stocky tank shapes while a tapered tank is obtained for the exergy optimisation. According to the TOPSIS method, the economic optimal solution appears to be the best trade-off for both fillers tested. Despite poorer thermophysical properties, the solution with ceramic from fly ashes shows similar exergy and economic performance as the machined ceramic solution (more than 96 % of exergy efficiency for 3.1 c€/kWhth), while the environmental footprint is greatly reduced (61 vs 87 ca.year). This tank has a diameter of 2.6 m and a height of 1.7 m. The particle diameter is 11 mm.

Optimized flow distributor for stabilized thermal stratification in a single-medium thermocline storage tank: A numerical and experimental study

This paper investigates the impact of flow injection on the temperature stratification inside single-medium thermocline storage tanks. Special focus is given on how to maintain the stable thermocline evolution during the dynamic charging or discharging operation, by using a new type of fluid diffuser, namely the Ring-Opening Plate Distributors (ROPDs). Firstly, the ROPDs are designed and the size distribution of the ring-shape openings is optimized by a simulation-based optimization algorithm. This diffuser concept has then been validated experimentally, showing its effectiveness in improving the charging and discharging efficiency of a laboratory-scale storage tank by up to 14.5% and 19.8%, respectively.Systematic experiments are performed to examine the effects of the injecting flow rate and temperature on the local transient temperature profiles and on the energy and exergy efficiencies of the thermocline tank. The stability range of operational parameters, characterized by the bulk Froude number (Fr < 3), has been determined for quasi-undisturbed advance of the thermocline. Beyond this stability range, simple tube-type diffuser is no longer capable of mitigating the impact of inflowing thermal jet. Additional structuration and optimization of the diffuser geometry become essential to stabilized the thermal stratification and to maintain a good thermal performance of the storage tank.

Machine Learning Approach to Predict the Performance of a Stratified Thermal Energy Storage Tank at a District Cooling Plant Using Sensor Data.

In the energy management of district cooling plants, the thermal energy storage tank is critical. As a result, it is essential to keep track of TES results. The performance of the TES has been measured using a variety of methodologies, both numerical and analytical. In this study, the performance of the TES tank in terms of thermocline thickness is predicted using an artificial neural network, support vector machine, and k-nearest neighbor, which has remained unexplored. One year of data was collected from a district cooling plant. Fourteen sensors were used to measure the temperature at different points. With engineering judgement, 263 rows of data were selected and used to develop the prediction models. A total of 70% of the data were used for training, whereas 30% were used for testing. K-fold cross-validation were used. Sensor temperature data was used as the model input, whereas thermocline thickness was used as the model output. The data were normalized, and in addition to this, moving average filter and median filter data smoothing techniques were applied while developing KNN and SVM prediction models to carry out a comparison. The hyperparameters for the three machine learning models were chosen at optimal condition, and the trial-and-error method was used to select the best hyperparameter value: based on this, the optimum architecture of ANN was 14-10-1, which gives the maximum R-Squared value, i.e., 0.9, and minimum mean square error. Finally, the prediction accuracy of three different techniques and results were compared, and the accuracy of ANN is 0.92%, SVM is 89%, and KNN is 96.3%, concluding that KNN has better performance than others.