Storage Prototype Research Articles

Characterization by key performance indicators of SFERA-III project to ALTAYR packed-bed prototype

The objective of this study is to assess the viability of implementing the methodology proposed in the SFERA-III project for the assessment of key performance indicators (KPIs) of thermal storage prototypes in a specific packed-bed device. SFERA-III project is an EU funded project aiming, among others, to upgrade the infrastructures and services related to Concentrating Solar Thermal technologies. In order to improve the quality of services in relation to the testing of thermal energy storage prototypes, a protocol and KPIs were defined and validated with different types of devices, though none of them was a packed-bed. This study elucidates the challenges encountered in the implementation of the protocol on a packed-bed prototype, alongside the proposed alternative solutions and their influence on the resulting KPIs. The analysis demonstrates that the SFERA-III Key Performance Indicators are an appropriate means of evaluating packed bed thermal energy storage prototypes. Consequently, the use of these KPIs as a standard is supported.

Microstructural Regulation of Co TCPP by Acetylene Black: Enhanced Electrochemical Performance for Wearable Supercapacitors

Abstract With the rapid development of wearable devices, flexible supercapacitors have become an important energy storage prototype due to their inherent flexibility and high power density. Two-dimensional metal-organic framework (2D MOF) nanosheets are widely used in energy storage systems due to their structural tunability and anisotropy. However, their high surface energy tends to lead to aggregation, which results in poor dispersion and rheology of formulated inks and inhomogeneity of printed electrodes. Existing methods involve surface modulation by capped organic ligands, yet ignore the inherent conductivity and stability of MOFs. To overcome the low conductivity and aggregation problems of 2D MOFs, we adopted a novel approach combining mechanical intercalation and surface functionalization of cobalt-based porphyrin frameworks (Co TCPP) with acetylene black (AB). The unique microstructure of the composite material leads to favorable changes in the electronic properties of AB, which reduces the overall internal resistance and promotes rapid charge transfer. For this purpose, we have prepared micro-supercapacitors (MSCs) using dispensing printing technology. This integrated material has excellent mechanical flexibility and maintains 92% specific capacitance even under extreme bending and torsion. This study highlights the potential of integrating 2D MOFs with carbon-based materials (e.g., acetylene black) for a variety of applications in wearable electronics, and provides a guiding scheme for future micro-modulation of 2D MOFs using conductive materials.

Development and optimization of sustainable and functional food packaging using false banana (Enset) fiber and zinc-oxide (ZnO) nanoparticle-reinforced polylactic acid (PLA) biocomposites: A case of Injera preservation

In a global context marked by food insecurity, it is essential for food science and packaging technology researchers and stakeholders to ensure the availability of safe and adaptable foods with minimal environmental impact. Achieving sustainability in food packaging requires multiple approaches, including the use of natural and biodegradable materials including cellulosic fibers. The current study aimed to develop and characterize and optimized an effective biocomposite food packaging/storing materials, specifically for a popular Ethiopian flatbread called injera, made from a grain called ‘Teff’ (Eragrostis tef). The proposed biocomposite food storage and packaging was designed by incorporating fiber-reinforcing materials, namely false banana, also called Enset fibers (EFs), and ZnO nanoparticles (ZnO NPs) into a polylactic acid (PLA) matrix. A central composite design (CCD) approach was used to evaluate the impact of the reinforcing Enset fibers (EFs) at 5 %, 15 %, and 25 % and ZnO NPs at 0 %, 5 %, and 10 % levels. The developed functional biocomposite packaging materials were tested and characterized for various properties, including mechanical strength, water activity, antifungal activity, and migration properties. The results showed that the inclusion of ZnO NPs improved the tensile strength, migration, and barrier properties, while the reinforcing fiber enhanced mechanical and migration properties but reduced barrier properties. The combined effect of the reinforcement fibers (EFs) and ZnO NPs led to further improvements in the mechanical strength and migration properties, though no interaction effect was observed on barrier properties. The optimal solution, consisting of 6.7 % ZnO nanoparticles and 6 % Enset fibers, resulted in a highly effective packaging and storage prototype that extended the freshness of the food for over eight days.

High-density and anti-clogging three-phase absorption heat storage with crystallization management

Three-phase sorption heat storage can significantly enhance the energy storage density (ESD) through the crystallization of salt-water working pair. However, the crystals will cause the clogging of solution circulation, making it difficult to be realized in absorption heat storage with liquid absorbent. In this work, the crystal management strategy is proposed for three-phase absorption heat storage. By controlling the crystallization ratio, energy storage enhancement and clogging prevention can be achieved simultaneously. Both theoretical and experimental analyses were carried out. A detailed thermodynamic model of the three-phase absorption heat storage cycle was established, by considering the change of crystallization ratio. A prototype of LiBr-water three-phase absorption heat storage with crystallization management which includes crystal filtering, high-level solution intake, crystal fusion by electric heating rods, and water flushing, was designed and fabricated. The anti-clogging design ensures the circulation of solution, efficient vapor absorption and crystal dissolution in discharging process, thus achieving high energy storage density and stable heat output simultaneously. The three-phase absorption heat storage prototype demonstrated high ESD of 220 kWh/m3 and 178 kWh/m3 with crystallization ratio of 0.41 and 0.26 under the space heating and hot water supplying conditions, respectively. Comparing with the absorption heat storage prototype without crystallization, this represents ESD enhancement of 102% ∼ 210%, which confirms the feasibility and superiority of the proposed crystal management strategies.

The Design of Refrigerated Portable Fish Storage Prototype for Small Scale Fisheries

The Design of Refrigerated Portable Fish Storage Prototype for Small Scale Fisheries

Experimental Demonstration of a Solar Powered High Temperature Latent Heat Storage Prototype

The challenge of imbalances between renewable energy supply and grid demand underscores the significance of energy storage in microgrids. This research presents an empirical assessment of the operational capabilities of a full-scale Electrical Thermal Energy Storage (ETES) prototype system named Thermal Energy Storage Power On Demand (TES.POD®), in solar-abundant and harsh desert conditions. The system incorporates a high-temperature commercial-scale latent heat thermal energy storage, integrated with a Stirling engine. Over a continuous span of 10 days, from September 26th to October 6th, 2022, the input and output power, as well as the heat transfer fluid temperatures during charging and discharging were monitored to assess the power block and system efficiencies. Results from the experiments reveal that this prototype effectively maintains a near-constant electricity production rate of 10.5 ± 1 kW for a discharge duration of 13 hours. Average cycle efficiency stands at 23%, while power block efficiency reaches 25%. These findings collectively suggest the system's potential for applications involving long duration thermal energy storage.

Prototype of Smart Grain Storage Based Internet of Things

Rice (Oryza sativa L.) is a crucial staple food, particularly in Indonesia, one of the largest rice-producing countries. Proper storage of rice grains is essential to maintain their quality and quantity. This research aims to develop a smart rice grain storage prototype based on the Internet of Things (IoT) that can monitor temperature, humidity, and light intensity in real-time. The method used is Design-Based Research (DBR), involving six stages: focus, understanding, definition, conception, creation, and testing. The prototype utilizes DHT22 sensors for temperature and humidity, LDR sensors for light intensity, and soil moisture sensors, all integrated with an ESP32 microcontroller. Data collected from the sensors are sent to a cloud-based platform for analysis and early warnings if storage conditions are unsuitable. The results indicate that the prototype effectively monitors storage conditions and provides accurate data. System testing shows that all components function according to specifications. This prototype helps maintain grain quality and reduce damage risk during storage. The use of IoT in grain storage enhances efficiency and reduces farmers' costs. Future research should focus on developing more advanced prototypes with automatic control features and mobile application integration.

Development and experimental study of a small-scale adsorption cold storage prototype with stable and tunable output for off-grid cooling

Comfort cooling is a growing demand in summer outdoor activities and work. Adsorption cold storage (ACS) can achieve long-term cold storage without insulation measures and release cold without requiring electricity input. However, the challenges, including unstable cooling output and huge volume, hinder its wide applications. In this study, a small-scale silica gel-water ACS prototype for off-grid cooling is developed and experimentally investigated under typical summer conditions. The heat pipe structure is employed in the adsorption bed for heat transfer enhancement and volume reduction. Valve opening control is utilized for cooling output stabilization and adjustment. The experimental results show that the prototype achieves 6.36 h of cooling output with the outlet air temperature of 25 °C and the average cooling power of 107.67 W under the environment conditions of 35 °C and 40 % RH, indicating an effective cold storage capacity of 685 Wh and an operating efficiency of 0.30. Furthermore, the stable output air temperature can be flexibly adjusted from 19 °C to 27 °C while maintaining the inlet air temperature at 35 °C during the discharging process. Notably, the charging environment temperature shows a minimal influence on the cooling output performance. The prototype's design is novel and applicable for portable cooling in outdoor off-grid scenarios.

1D modelling of a latent heat thermal energy storage prototype using boiling water as heat transfer fluid

This paper presents a numerical model to simulate the thermohydraulic behaviour of a shell-and-tubes Latent Heat Thermal Energy Storage (LHTES) during discharging period, involving a boiling heat transfer fluid (HTF). It is based on a 1D homogeneous approach for the HTF (water) and a 1.5D approach for the phase-change material (sodium nitrate) allowing calculation times significantly shorter than those of CFD. This approach has been validated with experimental data in a previous study for a LHTES with a monophasic HTF. The two highlights of this paper are as follows: On the one hand, computational fluid dynamics has been used to develop equivalent homogeneous materials for PCM side, integrating the thermal properties of the phase-change material and the helical and longitudinal fins present in the LHTES. On the other hand, the model uses the asymptotic correlation of Steiner and Taborek to describe boiling heat transfers and usual correlations for single phase heat transfers. The paper focuses on the validation of the model against experimental data from the InPower project. The prototype is a 340 kWh storage that has been tested under different conditions. The model reproduces the total energy retrieved during a system discharge with relative error of 8.5% and an absolute mean error of 8.23 kW on outlet power. The main weakness of the model is the homogeneous model for the HTF that generates error in water level and local temperatures.

Optimizing battery energy storage prototypes for improved resilience in commercial buildings: Gaussian mixture modeling and hierarchical analysis of energy storage potential

The increasing energy demand in commercial buildings has led to the adoption of photovoltaic (PV) systems as a viable solution. However, the gap between energy consumption and PV capacity in commercial buildings remains uncertain, and there is limited research on the potential for energy storage in different commercial building types. This study utilizes Gaussian mixture modeling to extract energy consumption and PV capacity patterns from diverse commercial buildings, using datasets provided by the Department of Energy. By employing hierarchical analysis, we investigate the energy storage potential of various commercial buildings based on the disparities between energy consumption and PV capacity patterns. Moreover, this study introduces innovative battery energy storage system (BESS) prototypes tailored to the specific needs of different commercial building types. These prototypes determine the optimal BESS capacity and charging schedules, providing an effective means of improving electrical resilience in commercial buildings. The findings reveal that medium offices, warehouses, and secondary schools require BESS capacities of 410kWh, 838kWh, and 349kWh, respectively, and recommend charging time windows of 9:00–17:00, 8:00–18:00, and 9:00–14:00, respectively. Additionally, the cost recovery period for Li-ion phosphate and ternary Li-ion batteries ranges from approximately 2.5 to 7.5 years and 4 to 8.2 years, respectively. The developed BESS prototypes based on energy storage potential offer resilience to commercial buildings during power outages caused by natural disasters and emergencies, helping to improve their electrical resilience. This study provides valuable insights into the potential for energy storage in commercial buildings and promotes the wider implementation of BESS in the commercial sector, contributing to the achievement of effective demand-side management.

Development and experimental investigation of full-scale phase change material thermal energy storage prototype for domestic hot water applications

The paper presents an experimental analysis of the full-scale phase change material (PCM) thermal energy storage (TES) prototype that is designed for use in domestic hot water preparation systems. The PCM-TES prototype is based on the external arrangement of organic PCM and a custom-made compact fin-and-tube type of heat exchanger. The prototype has been designed, constructed, and tested according to the Ecodesign Directive requirements for water heaters and hot water storage tanks. Several parameters have been analysed, including the heat transfer fluid (HTF) temperature and mass flow rate, heat transfer rate, accumulated and released energy, and quantity of domestic hot water (DHW) delivered. Additional attention was paid to the reliability and repeatability of the results. Experimental research allowed to determine the quantity and temperature of DHW at a constant mass flow rate of 0.1 kg/s. The prototype unit showed that it can deliver 99.1 l of hot water at 40 °C for up to 15 min and 39 s, while the use of lower temperature DHW (up to 37 °C) allows to increase the quantity of hot water delivered up to 156.2 l. Experimental results showed the viability of the prototype, areas for improvement and further possibilities for its optimization. Overall, the study results are relevant for developing latent heat thermal energy storage systems using fin-and-tube heat exchangers in tanks and the feasibility of integrating such systems into DHW systems.

Numerical investigations of a latent thermal energy storage for data center cooling

The thermal performance of a 115 L latent heat storage prototype for cooling data centers was investigated. Experimentally, the heat transfer power and heat absorbed by the heat exchanger during the charging and discharging processes were measured at two flow rates (5 and 10 L/min). Numerically, two phase-change models were developed using the enthalpy and effective heat capacity methods, respectively. The results showed that the enthalpy method provides an overall better prediction of the absorbed heat, whereas the other method only agrees well with the measured results during the melting process. Thus, it is suggested that further modification of the effective heat capacity with temperature improves the agreement between the results. For a volume flow rate of 5 L/min, the average heat transfer power predicted by the enthalpy model was 2290 W during the melting process and > 920 W during the solidification process due to the smaller temperature difference for heat transfer caused by supercooling. The prototype achieved the highest average heat exchange capacity rate when melted to a 50% of its total capacity. This study provides a baseline for predicting and improving the thermal performance of latent heat storage.

Gravity-induced virtual clocking effect in large-capacity/low-head pumped hydro energy storage system with horizontal shaft

Significant gravity effects in a large-capacity/low-head pumped hydro energy storage system with horizontal shaft can destroy the axisymmetric inner flow structures in pump mode compared with its hydraulic model. For the stationary guide-vane region, this makes the inflow condition of each vane change with its circumferential installation position and thus causes a virtual clocking effect between the visible guide-vanes and the invisible gravity. The virtual clocking effect may change the hydraulic performance and induce instability risks, but its specific influence is still unclear. In this article, for a low-head pumped hydro energy storage prototype system with horizontal shaft, four virtual clocking schemes, namely the top guide-vane inlet edge and the gravity direction staggering 0/4, 1/4, 2/4 and 3/4 passage interval angle, were established, and a comparative investigation on hydraulic performance in the optimal pump mode was carried out. Firstly, the pressure polarization oscillation is observed in the impeller region under different schemes. The differences in the polarization degree do not exceed 1%, but the circumferential distributions of the peak-to-peak values of pressure fluctuations at the impeller outlet show a phase difference, which should be considered in the circumferential support structures. Secondly, the partial flow separation is observed in the guide-vane region under different schemes, and the flow deviation ratio between the left and right sides at the guide-vane outlet exhibits differences of up to 10%, which cannot be ignored for a huge system. The scheme with staggering 1/4 passage interval angle exhibits the least flow deviation ratio while the scheme with staggering 3/4 passage interval angle exhibits the greatest flow deviation ratio. Overall, to ensure the hydraulic stability of the large-capacity/low-head pumped hydro energy storage system with horizontal shaft, the virtual clocking scheme with staggering 1/4 passage interval angle is recommended for the energy engineering.

Training industrial engineers in Logistics 4.0

The Fourth Industrial Revolution is no longer a future milestone, but a reality. Companies in different industrial sectors around the world are already incorporating Industry 4.0 skills and technologies into their philosophy and practices. This new industrial era requires universities to adapt and train future engineers in these skills and competencies. One area of Industry 4.0 that is developing at a frenetic pace is logistics. The set of principles, knowledge, and techniques of Industry 4.0 applied to logistics is referred to as Logistics 4.0. Training students in Logistics 4.0 is crucial for their professional future in this new industrial scenario. One of the learning strategies that can be most fruitful in this regard is Kolb’s experiential learning model, which can be exploited through final projects. In this sense, this work illustrates an approach to acquire these skills through the design of a laboratory prototype storage system using low-cost technologies for academic use such as LEGO Mindstorms and Android Studio together with smartphones. By following this approach, engineering students will “learn by doing” the concepts and skills they will need in their future careers in Logistics 4.0.

CFD modelling of an indirect thermocline energy storage prototype for CSP applications

Thermocline thermal energy storage is a (potentially) cost-effective alternative to the more widespread two-tank solution, as both the hot and the cold medium are stored in a single tank.An innovative single-medium indirect thermocline technology was recently developed by ENEA and a prototype was experimentally tested at the Casaccia laboratories. The storage tank is equipped with two flat-coil heat exchangers (HXs) located at the bottom and at the top of the tank, for the charge and discharge phases, respectively. The storage medium is a mixture of molten salt (Hitec XL) and the heat transfer fluid is a mineral oil (Delcoterm Solar E15). An internal vertical channel, which assists the motion of the storage medium during the charge and discharge transients, connects the two HXs.In this paper, a detailed, transient 2D axisymmetric Computational Fluid Dynamics (CFD) model of the prototype has been developed. The model simulates the charge and discharge transients, determining the heat losses and the temperature distribution of the molten salt in the tank. The computational domain includes the storage medium, the tank insulated walls and the main components immersed in the molten salt, i.e., the heat exchangers and the vertical channel.The model has been first calibrated by best-fitting the data measured during a test conducted without any thermal load, then validated against another independent set of experimental data.A first comparison against a charge transient showed some discrepancies between the computed and the measured temperatures of the salt, which could be explained by assuming the presence of a bypass at the location of the HXs. This assumption is discussed and justified in the paper. The CFD domain has then been modified to include the bypass, and this allowed to successfully validate the model against experimental data in both charge and discharge phases.The validated model is finally exploited to assess how a variation in the diameter of the internal vertical channel could affect the thermal performance of the storage system in a charge transient. The results indicate that decreasing the channel diameter leads to an increase of the salt temperature at the very top of the tank at the cost of a longer time to fully charge the storage.

Selective Electrochromic Regulation for Near-Infrared and Visible Light via Porous Tungsten Oxide Films with Core/Shell Architecture.

Dual-band electrochromic smart windows have become a research hotspot owing to their unique ability to selectively control near-infrared (NIR) and visible (VIS) light. However, the design and exploitation of dual-band electrochromic films are still an extreme challenge due to the scarcity of relevant high-performance materials. To solve this issue, we here proposed a type of porous WO3 film with nanowires/nanoparticles core/shell architecture as a promising candidate, endowing smart windows with a dual-band electrochromic feature. Moreover, the mechanism of the dual-band electrochromism is illustrated by the response of the transmittance spectra in Li+-based or TBA+-based electrolytes to distinguish the electrochemical behavior and the cyclic voltammetry to determine the degree of diffusion-limited kinetics. Our results indicate that the dual-band electrochromic performance is credited to the progressive electrochemical reduction procedure, in which the capacitive charging process gives rise to NIR regulation and the following ion intercalation contributes to VIS light modulation. Furthermore, we develop a dual-band electrochromic energy storage prototype device utilizing the porous WO3 film. This work describes a judicious strategy for designing dual-band electrochromic films, promoting the evolution of dual-band electrochromic technology.

Optimization of heat removal and radiation protection of dry cask storage for MTR spent nuclear fuel

To provide a solution for the limited storage space in wet-type storage in Indonesia's material testing reactor (MTR) spent nuclear fuel (SNF) storage, a study on dry cask storage for MTR SNF is needed. This study designed, simulated, and experimentally calculated the safety parameters and the manufacturing cost of dry cask storage simultaneously. The optimization results were validated and analyzed using experimental data from a dry cask storage prototype. Decision variables and constraints were provided as inputs into the MATLAB software to obtain three optimized conditions: safety, cost, and multi-objective optimized conditions. The multi-objective optimization results demonstrated that the thickness of dry storage design concrete and lead (Pb) are 0.06 and 0.51 m, respectively. The height and width of the vent are 0.15 and 0.5 m, respectively, and the vent elevation difference is 2.43 m. For five variables, the optimum value for the canister surface temperature is 66.8 °C and the cost required to manufacture this dry storage is USD 147,827. Moreover, MicroShield validation revealed that the dry cask storage surface exposure is 104.8 mR/h, which is lower than the safe limit of the maximum value specified as 160 mR/h. The simulation of the canister surface temperature using ANSYS Fluent showed that the surface temperature value is close to the calculations performed in MATLAB. Temperature validation of experimental data from the dry storage prototype indicated that the temperature obtained via theoretical and experimental calculations is relatively close: 45.2 and 51.3 °C. This research can be developed to other types of dry storage design by changing the value of the decision variables that is appropriate for the dry storage type to be designed.

Experimental study and computational approach prediction on thermal performance of eutectic salt inside a latent heat storage prototype

Experimental study and computational approach prediction on thermal performance of eutectic salt inside a latent heat storage prototype

Triggering Xylitol crystallization in a 42 kWhth shell and tubes latent heat thermal energy storage system

Xylitol is a very promising Phase Change Material for district heating networks decentralized Latent Heat Thermal Energy Storages. However, it presents a high and persistent supercooling that requires the implementation of specific ways to trigger its crystallization. In previous works, the coupling of bubbling and seeding has been successfully tested as an efficient way to trigger Xylitol crystallization in small-scale crystallizers. The present work first studies the feasibility of using Xylitol as PCM in a 42 kWhth shell and tubes Latent Heat Thermal Energy Storage prototype integrating a bubbling and seeding system. Then, the benefits of optimizing the seeding step is discussed. Indeed, if the coupling between bubbling and seeding results in a fast and reproducible PCM crystallization, optimizing the seeding step allows to completely remove the effects of Xylitol supercooling on the restituted temperature levels. Another effect of bubbling in a Latent Heat Thermal Energy Storage is also brought to light: during the beginning of the discharge, a vertical temperature homogenization is observed in the liquid PCM. The consequences of this vertical temperature homogenization on the heat transfers and the performances of the storage are discussed.

Efficient erasure-coded data updates based on file class predictions and hybrid writes

A small update write can lead to a partial write to an erasure coding group in erasure-coded storage systems, resulting in a time-consuming write-after-read. This paper presents a data delta and logging based writing approach, named DETOG, to achieve fast partial writes. DETOG classifies files into non-write-only and write-only using machine learning, then adopts different write schemes to perform partial writes according to file classes. For non-write-only files, DETOG uses data deltas that are the differences between latest data values and original data values, instead of parity deltas to reconstruct the failed data. For non-write-only files, DETOG performs in-place data updates and log-based parity updates, so as to balance the overhead of data updates and reads. We implement DETOG on the newly designed prototype storage system to perform performance evaluation. The results of extensive experiments on real-world traces showed that DETOG significantly improved system throughput compared with state-of-the-art methods.