Search Results (419)

The rapid advancement of energy collection and storage systems (ECSSs) is fundamentally reshaping global energy markets and accelerating the transition toward low-carbon energy systems. This study provides a comprehensive assessment of the economic benefits and systemic effects of advanced ECSS technologies, including photovoltaic-thermal (PV/T) hybrid systems, advanced batteries, hydrogen-based storage, and thermal energy storage (TES). Through a mixed-methods approach combining techno-economic analysis, macroeconomic modeling, and policy review, we evaluate the cost trajectories, performance indicators, and deployment impacts of these technologies across major economies. The paper also introduces a novel economic-mathematical model to quantify the long-term macroeconomic benefits of large-scale ECSS deployment, including GDP growth, job creation, and import substitution effects. Our results indicate significant cost reductions for ECSS by 2050, with battery storage costs projected to fall below USD 50 per kilowatt-hour (kWh) and green hydrogen production reaching as low as USD 1.2 per kilogram. Large-scale ECSS deployment was found to reduce electricity costs by up to 12%, lower fossil fuel imports by up to 25%, and generate substantial GDP growth and job creation, particularly in regions with supportive policy frameworks. Comparative cross-country analysis highlighted regional differences in economic effects, with the European Union, China, and the United States demonstrating the highest economic gains from ECSS adoption. The study also identified key challenges, including high capital costs, material supply risks, and regulatory barriers, emphasizing the need for integrated policies to accelerate ECSS deployment. These findings provide valuable insights for policymakers, industry stakeholders, and researchers aiming to design effective strategies for enhancing energy security, economic resilience, and environmental sustainability through advanced energy storage technologies. Full article

With the expansion of renewable energy deployment, characterized by its variability, stabilizing power and heat supply has become a critical issue. To address this challenge, large-scale and low-cost energy storage technologies are essential, and thermal energy storage (TES) is considered one of the promising solutions. Among large-scale TES systems, Circulating Fluidized Bed TES (CFB TES) is a technology that stores energy as sensible heat in high-temperature sand and utilizes it for power generation using high-temperature steam or steam turbines when needed, offering high compatibility with existing infrastructure. While the underlying circulating fluidized bed system is a well-established technology, precise control of circulating particle flow rates remains a technical challenge due to differences from conventional circulating fluidized beds. In this study, we propose a mechanically simple and thermally durable flow control system that combines an orifice for stepwise flow adjustment and a J-valve (loop seal) for on/off particle transport. In this study, the flow characteristics of the orifice, the minimum fluidization velocity ($u_{mf}$≈ 0.076 m/s), the transient stabilization behavior, and the effects of downstream pressure (back pressure) were evaluated in lab-scale experiments. The results showed that particle flow rate follows a power-law relationship with the orifice diameter, stabilizes when fluidization velocity exceeds $u_{mf}$, and decreases linearly with increasing back pressure. Based on these findings, we established design guidelines incorporating orifice sizing, fluidization control, and back pressure compensation. Full article

Cryogenic Energy Storage (CES) has emerged as a promising solution for large-scale and long-duration energy storage, offering high energy density, zero local emissions, and compatibility with intermittent renewable energy sources. This systematic review critically examines recent advances in the numerical modeling of CES systems, with the objective of identifying prevailing methodologies, emerging trends, and existing research gaps. The studies analyzed are classified into three main categories: global thermodynamic modeling, simulation of specific components, and transient dynamic modeling. The findings highlight the continued use of thermodynamic models due to their simplicity and computational efficiency, alongside a growing reliance on high-fidelity CFD and transient models for more realistic operational analyses. A clear trend is also observed toward hybrid approaches, which integrate deterministic modeling with machine learning techniques and response surface methodologies to enhance predictive accuracy and computational performance. Nevertheless, significant challenges persist, including the absence of multiscale integrative models, the scarcity of high-resolution experimental data under transient conditions, and the limited consideration of operational uncertainties and material degradation. It is concluded that the development of integrated numerical frameworks will be critical to advancing the technological maturity of CES systems and ensuring their robust deployment in real-world energy transition scenarios. Additionally, the review also discusses local thermal non-equilibrium (LTNE) conditions, the influence of geometric and operational parameters, and the role of multidimensional and multi-region modeling in predicting thermal and exergy performance of packed-bed TES within LAES cycles. Full article

This review provides a comprehensive analysis of advanced control strategies and operational optimization of energy systems, focusing on heat pumps, with an emphasis on their role in enhancing energy efficiency and operational flexibility. The study concentrates on methods supported by artificial intelligence algorithms, highlighting Model Predictive Control (MPC), Reinforcement Learning (RL), and hybrid approaches that combine the advantages of both. These methods aim to optimize both the operation of heat pumps and their interaction with thermal energy storage (TES) systems, renewable energy sources, and power grids, thereby enhancing the flexibility and adaptability of the systems under real operating conditions. Through a systematic analysis of the existing literature, 95 studies published after 2019 were examined to identify research trends, key challenges such as computational requirements and algorithm interpretability, and future opportunities. Furthermore, significant benefits of applying advanced control compared to conventional practices were highlighted, such as reduced operational costs and lower CO₂ emissions, emphasizing the importance of heat pumps in the energy transition. Thus, the analysis highlights the need for digital solutions, robust and adaptive control frameworks, and holistic techno-economic evaluation methods in order to fully exploit the potential of heat pumps and accelerate the transition to sustainable and flexible energy systems. Full article

With the continuous increase in the proportion of renewable energy in the power grid, enhanced operational flexibility of the power system is required. As baseload generators, combined heat and power (CHP) units are prime candidates for flexibility retrofits that guarantee grid stability. Among the available options, molten-salt thermal energy storage (TES) offers an energetically efficient route to decouple heat and electricity production in CHP plants. In this study, a 660 MW ultra-supercritical coal-fired unit is taken as the object of investigation. Sixteen technical routes incorporating steam extraction and electric heating for thermal energy storage and discharging are systematically designed. Results demonstrate that all the combined schemes significantly improve the operational flexibility of the unit. Among them, the C1-S1 configuration exhibits the most outstanding overall economic performance, with a six-hour thermal storage capacity of 294.34 MWh. The system exergy destruction is measured at 6258 kW, while the round-trip efficiency and thermal efficiency are determined to be 81.11% and 45.48%, respectively. Full article

Molten salt thermal energy storage (TES) provides an efficient solution to improve the flexibility of combined heat and power (CHP) plants. This study investigated two operation modes of TES: the Power-Augmenting TES Mode (Mode 1), which enhances power generation flexibility, and the Heating-Augmenting TES Mode (Mode 2), which improves the flexibility of industrial steam supply. Based on a validated thermodynamic model, the flexibility, energy efficiency, exergy efficiency, and economic performance of the integrated system are evaluated. Results show that Mode 1 offers stronger peak-shaving capability, while Mode 2 achieves comparable peak-topping performance and is more suitable for high industrial heating load scenarios due to its inherent heat–power decoupling effect. Mode 2 exhibits more pronounced energy efficiency improvement, whereas both modes reach identical maximum exergy efficiency. Additionally, the integration of molten salt TES significantly enhances profitability, increasing annual profit to 97.3 million RMB under Mode 1 and 85.4 million RMB under Mode 2 from a baseline of 79.7 million RMB. While Mode 1 generates higher profit at lower heating loads, Mode 2 becomes progressively more advantageous as industrial heating load increases. Full article

Technical constraints to be faced in microgrids have become more frequent with high renewable integration. In this context, Thermal Energy Storage (TES) has emerged as a promising solution to enable consumers’ flexibility to contribute to the solution of such operational issues. This paper examines the integration of the novel system ECHO-TES (a Thermal Energy Storage System developed within the European Project ECHO) in microgrids to address technical constraints, utilizing OpenDSS and Python simulations. Building on that, the Efficient Compact Modular Transaction Simulation System (ECHO-TSS) adds a layer of virtual automated transactions, coordinating multiple ECHO-TES assets to simulate not only energy flows and electricity consumption, but also the associated economic interactions. The study explores the critical role of TES in enhancing microgrid efficiency, flexibility, and sustainability, particularly when coupled with renewable energy sources. By analyzing diverse demand scenarios, the research aims to assess its impact on grid stability and management. The paper highlights the importance of advanced modeling tools like OpenDSS in simulating complex microgrid operations, including the dynamic behavior of TES systems. It also investigates demand-side management strategies and the potential of TES to mitigate challenges associated with renewable energy variability. The findings contribute to the development of robust, adaptive microgrid systems and support the global transition towards sustainable energy infrastructure. Full article

The integration of molten salt thermal energy storage (TES) into coal-fired power units offers a viable strategy to improve operational flexibility. However, existing studies have predominantly employed steady-state models to quantify the extension of the unit’s load range, while failing to adequately capture dynamic performance. To address this gap, this study utilizes a validated dynamic model of a molten salt TES-integrated power unit to investigate its dynamic characteristics during frequency regulation. The results indicate that molten salt TES exhibits significant asymmetry between its charging and discharging processes in terms of both the speed and magnitude of the power response. Moreover, under load step scenarios, the TES-integrated unit increases its ramp rate from 1.5% to 8.6% P_N/min during load decrease, and from 1.5% to 6.3% P_N/min during load increase. Under load ramping scenarios, molten salt TES reduces the integral of absolute error (IAE) to 0.15–0.25 MWh, significantly lower than the 3.21–4.59 MWh of the standalone unit. Additionally, in response to actual AGC commands, molten salt TES reduces non-compliant operation time from 729 s to 256 s and decreases the average power deviation by 33.6%. These improvements also increase the ancillary service revenue by 37.7%, from CNY 3364 to CNY 4632 per hour. Full article

This study presents a comprehensive dynamic system analysis of air-based Brayton batteries for the coupled generation of electricity, heat, and cooling. Building upon a previously published structural concept study, the most promising system architectures were modeled and evaluated using quasi-stationary simulations with dynamically designed thermal energy storage (TES) in Ebsilon Professional^®. The results show round-trip efficiencies (RTEs) of up to 50% for pure electricity generation and round-trip utilizations (RTUs) exceeding 85% for combined heat and power. Integration of waste heat further increases RTU to more than 100%, albeit at the expense of electrical efficiency. Dynamic simulations demonstrate stable operation with load gradients up to 2 MW min⁻¹, highlighting suitability for flexible industrial and grid applications. Regenerator-based TES exhibits the most favorable trade-off between efficiency and cost, while hybrid configurations of solid and liquid media offer additional optimization potential. The estimated investment costs range between 200 and 800 EUR/kWh_el, comparable to other large-scale Carnot battery systems. The findings provide a validated framework for the techno-economic design and control of next-generation Brayton battery systems and lay the foundation for experimental validation and pilot-scale implementation. Full article

To alleviate the peak-shaving pressure caused by large-scale renewable energy integration, this paper proposes a bilateral trading strategy for wind–thermal energy storage (TES) systems. Based on the classification of TES electricity-receiving and heat-receiving pathways, the distinct electrical and thermal flexibilities of TES are quantified, and a Stackelberg game is formulated in which TES enterprises bid quantities, whereas wind farms bid prices. By doing so, the complex coupling between TES and thermal power units is clearly decoupled, significantly enhancing the market participation of both TES enterprises and wind farms. Finally, simulations using operational data from a real wind farm with 1665 MWh of curtailed wind demonstrate that the proposed method accommodates 61.26% of the curtailed energy and raises the net-load valley by 131.6 MW, confirming its effectiveness and practical feasibility of the proposed strategy. Full article

Paraffin-based phase change materials (PCMs) have emerged as promising candidates for thermal energy storage (TES) applications due to their high latent heat, chemical stability, and low cost. However, their inherently low thermal conductivity and the risk of leakage during melting–solidification cycles significantly limit their practical performance. To address these limitations, numerous studies have investigated composite PCMs in which paraffin is incorporated into porous supporting matrices. Among these, diatomite has garnered particular attention due to its high porosity, large specific surface area, and chemical compatibility with organic materials. Serving as both a carrier and stabilizing shell, diatomite effectively suppresses leakage and enhances thermal conductivity, thereby improving the overall efficiency and reliability of the PCM. This review synthesizes recent research on paraffin–diatomite composites, with a focus on impregnation methods, surface modification techniques, and the influence of synthesis parameters on thermal performance and cyclic stability. The mechanisms of heat and mass transport within the composite structure are examined, alongside comparative analyses of paraffin–diatomite systems and other inorganic or polymeric supports. Particular emphasis is placed on applications in energy-efficient buildings, passive heating and cooling, and hybrid thermal storage systems. The review concludes that paraffin–diatomite composites present a promising avenue for stable, efficient, and sustainable phase change materials (PCMs). However, challenges such as the optimization of pore structure, long-term durability, and large-scale manufacturing must be addressed to facilitate their broader implementation in next-generation energy storage technologies. Full article

This study examines the thermal performance of phase change material (PCM)–metal foam composites under base heating, a configuration more relevant to compact thermal energy storage (TES) and electronics-cooling applications, compared to the widely studied side-heated case. Metal foams with pore densities of 10, 20, and 40 PPI, but identical porosity (volumetric value), were impregnated with two PCMs (paraffin RT55 and RT64HC) and tested under varying heat fluxes. The thermophysical properties of three PCMs (RT42, RT55, and RT64HC) were first characterized using the T-history method. A control case consisting of pure PCM revealed significant thermal lag between the heater and the PCM, whereas the inclusion of a metal foam improved temperature uniformity and accelerated melting. The results showed that PPI variation had little influence on melting completion time, while PCM type, viz., melting temperature, strongly affected duration. Heat flux was the dominant parameter: higher input power substantially reduced melting times, although diminishing returns were observed at elevated heat fluxes. An empirical correlation from the literature, originally developed for side-heated foams, was applied to the base-heated configuration and reproduced the main melting trends, though it consistently underpredicted completion times at high fluxes. Overall, embedding PCMs in metal foams enhances heat transfer, mitigates localized overheating, and enables more compact and efficient TES systems. Future work should focus on developing correlations for non-adiabatic cases, exploring advanced foam architecture, and scaling the approach for practical energy storage and cooling applications. Full article

Thermal energy storage (TES) systems are crucial for industries to overcome the temporal misalignment between heat demand and availability, while also reducing greenhouse gas emissions. This is fundamental for increasing industrial production efficiency and promoting renewable energy sources, such as solar energy. Among various TES solutions (sensible, latent, and thermochemical), combined sensible/latent heat TES (CSLHTES) is attracting more interest. It combines the ideal characteristics of individual sensible or latent heat storage technologies: high stored energy density, compactness, high efficiency, stable heat supply temperature, and good power output. This work experimentally evaluates the thermal behavior and potential improvements of a CSLHTES system. This system, named HyTES, consists of two series-connected TES units—one sensible and one latent—operating within a 180–280 °C range, to meet typical industrial application requirements. A test procedure was developed to define key performance indexes (KPIs). The results confirm that CSLHTES systems generally show improved performance compared to individual units. This indicates that further analysis of this approach is justified, moving beyond just energy and exergy perspectives to also include economic and environmental impacts. Full article

Thermal energy storage (TES) plays a vital role in advancing energy efficiency and sustainability, with phase change materials (PCMs) receiving significant attention due to their high latent heat storage capacity. Nevertheless, conventional PCMs face critical challenges such as leakage, phase separation, and low thermal conductivity, which hinder large-scale applications. Encapsulation strategies have been developed to address these issues, and bio-based composite materials are increasingly recognised as sustainable alternatives. Materials such as lignin, nanocellulose, and biochar, as well as hybrid formulations with graphene and aerogels, show promise in improving thermal conductivity, mechanical integrity, and environmental performance. This review evaluates bio-based encapsulation approaches for PCMs, examining their effectiveness in enhancing heat transfer, durability under thermal cycling, and scalability. Applications in solar energy systems, building insulation, and electronic thermal regulation are highlighted, as are emerging AI-driven modelling tools for optimising encapsulation performance. Although bio-based PCM composites outperform conventional systems in terms of thermal stability and multifunctionality, they still face persistent challenges in terms of cost-effectiveness, scalability, and long-term reliability. Future research on smart, multifunctional PCMs and advanced bio-nanocomposites is essential for realising next-generation TES solutions that combine sustainability, efficiency, and durability. Full article

This review presents a technology roadmap for Thermal Energy Storage (TES) systems operating in the medium-temperature range of 100–300 °C, a critical window that accounts for approximately 37% of industrial process heat demand in Europe. Decarbonising this segment is essential to meeting climate targets, especially in sectors that are reliant on fossil-fuel-based steam. The study analyses 11 TES technologies, including sensible, latent, and thermochemical systems, covering both mature and emerging solutions. Each technology is evaluated based on technical, environmental, and socio-economic key performance indicators (KPIs), such as energy density (up to 200 kWh/m³), cost per storage capacity (€2–100/kWh), and technological readiness level (TRL). Sensible heat technologies are largely mature and commercially available, while latent heat systems—especially those using nitrate salts—offer promising energy density and cost trade-offs. Thermochemical storage, though less mature, shows potential in high-cycle applications and long-term flexibility. The review highlights practical configurations and integration strategies and identifies pathways for research and deployment. This work offers a comprehensive reference for stakeholders aiming to accelerate industrial decarbonisation through TES, particularly for applications such as drying, evaporation, and low-pressure steam generation. Full article