Search Results (33)

With the large-scale grid connection of renewable energy and the surge of peak power system demand, liquid carbon dioxide energy storage technology has become a research hotspot due to its high energy density and environmental friendliness. However, most of the existing research focuses on the steady-state performance of the system, and the parameter coupling and transient response characteristics under dynamic operating conditions are not yet clear. To this end, this paper constructs a dynamic simulation model of a 10 MW-class liquid carbon dioxide energy storage (LCES) based on the Simulink platform, focuses on the coupling effects of the compressor inlet temperature, pressure, and mass flow rate and the expander inlet mass flow rate on the system parameters, and reveals the dynamic correlation between the system work and the state of charge value of the tank under the variable power working condition. The results show that the system’s round-trip efficiency (RTE) is 65.3% under design conditions, and the energy density reaches 34.79 kW·h·m⁻³. Perturbation analysis shows that when the compressor inlet temperature rises from 283.15 K to 303.15 K, the power consumption fluctuates in the range of 96.84% to 102.99% under design conditions. The inlet pressure perturbation (0.5~1.5 bar) will cause the power consumption of the compressor to change by 80.2%. In variable power operation, the state of charge value of the high-pressure liquid tank level in the energy storage stage rises from 0 to 84.89%, and the state of charge value of the high-pressure liquid tank level in the energy release stage decreases from 84.89% to 31.48%. The dynamic model proposed in this paper can accurately capture the transient response characteristics of the system and provide theoretical support for the optimization design and engineering application of LCES. Full article

Motor vehicles in transport, as one of the important sectors of the economy, emit a significant amount of carbon dioxide and other products in the form of exhaust gases, which are harmful to human health. The emission of exhaust gases from motor vehicles is limited by appropriate regulations in accordance with environmental goals, such as the Paris Climate Agreement. Reduced emissions and fuel (energy) consumption is mainly achieved by applying modern technologies for the production of internal combustion engines; transitioning to cleaner fuels, such as renewable natural gas or biomethane; and using alternative propulsion systems. Biomethane stored in a liquid state in on-board reservoirs has advantages in truck transport, ships, and air traffic. The reason for this is due to the higher concentration of energy per unit volume of the reservoirs and the lower storage pressure and thus higher safety compared to the high-pressure storage option (compressed biomethane). The presented research is related to a proposition regarding the design of drive systems of city buses using biomethane as fuel in cases when fuel is stored on-board the vehicle as gas in a compressed aggregate state. In this study, the results of a calculation method regarding the roof-supporting structure of an experimental bus with gas reservoirs under higher pressure are discussed as well. This study also presents the possibility of reducing harmful emissions if biomethane is used instead of conventional fuels as a transitional solution to electric-powered vehicles. For the sake of comparison, it is suggested that the engaged energy and the amount of produced carbon dioxide emissions within the drive systems of different fuels are calculated according to the recommendations of the standard EN16258:2012. Full article

Energy storage stations (ESSs) need to be charged and discharged frequently, causing the battery thermal management system (BTMS) to face a great challenge as batteries generate a large amount of heat with a high discharge rate. Supercritical carbon dioxide (SCO₂) is considered a promising coolant because of its favorable properties, including non-flammability, high dielectric strength and low cost for the BTMS. The heat of a battery can be absorbed to a great extent if there is a small temperature rise because as the fluid temperature approaches a pseudo-critical temperature, the specific heat capacity of SCO₂ reaches its peak. In this study, a periodic model of the unit BTMS is established, and a numerical simulation is implemented to investigate the effects of different boundary conditions on the heat dissipation of a battery pack. The flow and heat transfer characteristics of SCO₂ in the liquid cold plate (LCP) of a battery pack with an extreme discharge rate are revealed. The results show that SCO₂ is more preferably used as a coolant compared to water in the same conditions. The maximum temperature and the temperature difference in the battery pack are reduced by 19.22% and 79.9%, and the pressure drop of the LCP is reduced by 40.9%. In addition, the heat transfer characteristic of the LCP is significantly improved upon increasing the mass flow rate. As the operational pressure decreases, the pressure drops of SCO₂ decrease in the LCP. Overall, the maximum temperature and the temperature difference in the battery pack and the pressure drops of the LCP can be effectively controlled by using a coolant made out of SCO₂. This study can provide a reference for the design of BTMSs in the future. Full article

As environmental pollution has become a global concern, regulations on carbon emissions from maritime activities are being implemented, and interest in using renewable energy as fuel for ships is growing. Hydrogen, which does not release carbon dioxide and has a high energy density, can potentially replace fossil fuels as a renewable energy source. Notably, storage of hydrogen in a liquid state is considered the most efficient. In this study, a 0.7 m³ liquid hydrogen fuel tank suitable for small vessels was designed, and a structural analysis was conducted to assess its structural integrity. The extremely low liquefaction temperature of hydrogen at −253 °C and the need for spatial efficiency in liquid hydrogen fuel tanks make vacuum insulation essential to minimize the heat transfer due to convection. A composite insulation system of sprayed-on foam insulation (SOFI) and multilayer insulation (MLI) was applied in the vacuum annular space between the inner and outer shells, and a tube-shaped supporter made of a G-11 cryogenic (CR) material with low thermal conductivity and high strength was employed. The material selected for the inner and outer layers of the tank was STS 316L, which exhibits sufficient ductility and strength at cryogenic temperatures and has low sensitivity to hydrogen embrittlement. The insulation performance was quantitatively assessed by calculating the boil-off rate (BOR) of the designed fuel tank. Structural integrity evaluations were conducted for nine load cases using heat transfer and structural analyses in accordance with the IGF code. Full article

The increase in the exploration of renewable energy sources intensifies the need for efficient storage solutions to mitigate the inherent intermittence of these sources. Among the available technologies, cryogenic energy storage (CES) systems stand out as a major and promising technology due to their high scalability, energy efficiency, and potential for integration with other systems. This paper deals with cryogenic approaches, focused on Liquid Air Energy Storage (LAES). Several topics are addressed, including the characterization of the CES systems, their working principle, with special relevance to efficiency and temperature/entropy diagram, the conception and the technical challenges, design, and construction of CES. LAES demonstrates energy efficiencies ranging from 45% to 70%, potentially reaching up to 75% with the integration of complementary technologies, with capital costs ranging from 900 EUR/kW to 1750/EUR/kW. Carbon dioxide (CO₂)-based systems, while more energy-efficient (40% to 60%), face significant barriers due to high infrastructure costs. Additionally, hybrid configurations that combine advanced thermal cycles and waste heat management achieve efficiencies between 55% and 80%, showing adaptability in complex energy scenarios. In comparison with alternatives such as batteries and Compressed Air Energy Storage (CAES), despite economic and technological limitations, CES systems have a promising role in the global energy transition, particularly with anticipated advancements that will enhance their competitiveness and economic viability. Full article

The increasing concentration of carbon dioxide (CO₂) in the atmosphere is a significant contributor to global warming and climate change. Effective CO₂ capture and storage technologies are critical to mitigating these impacts. This review explores various materials used for CO₂ capture, focusing on the latest advancements and their applications. The review categorizes these materials into chemical and physical absorbents, highlighting their unique properties, advantages, and limitations. Chemical absorbents, such as amine-based solutions and hydroxides, have been widely used due to their high CO₂ absorption capacities and established technological frameworks. However, they often suffer from high energy requirements for regeneration and potential degradation over time. Recent developments in ionic liquids (ILs) and polymeric ionic liquids (PILs) offer promising alternatives, providing tunable properties and lower regeneration energy. Physical absorbents, including advanced solvents like nanofluids and ionic liquids as well as industrial processes like selexol, rectisol, and purisol, demonstrate enhanced CO₂ capture efficiency under various conditions. Additionally, adsorbents like activated carbon, zeolites, metal-organic frameworks (MOFs), carbon nanotubes (CNTs), and layered double hydroxides (LDHs) play a crucial role by providing high surface areas and selective CO₂ capture through physical or chemical interactions. This paper summarizes the state of research on different materials and discusses their advantages and limitations while being used in CO₂ capture technologies. This review also discussed multiple studies examining the use of catalysts and absorption mechanisms in combination with different sorbents, focusing on how these approaches enhance the efficiency of absorption and desorption processes. Through a comprehensive analysis, this review aims to provide valuable insights into the type of materials that are most suitable for CO₂ capture and also provides directions for future research in this area. Full article

In view of the carbon emission reduction and new energy consumption problems in the integrated energy system (IES), this paper, for the first time, combines power to gas (P2G) with liquid carbon dioxide energy storage (LCES) and takes demand response (DR) into account simultaneously to construct a new type of IES capacity configuration optimization model. Firstly, based on the operation characteristics and coupling features of various devices within the system, the IES model was constructed. Meanwhile, the electricity, heat, and cold DR models were, respectively, established according to price-based and incentive-based methods. Finally, a two-layer collaborative optimization configuration model was built, with the upper layer aiming to minimize the annual total cost of the system and the lower layer aiming to minimize the annual operation cost of the system. Through case studies, the effectiveness of the established model was verified, and the impacts of DR, P2G, and LCES on the system capacity configuration results, economic efficiency, and environmental friendliness were investigated. Additionally, the impact of natural gas prices on the system optimization results was studied. The results showed that considering LCES and P2G could reduce the cost of the IES by 7.26% and the carbon emissions of the system by 31.03%, verifying the effectiveness of the proposed method and providing a feasible solution for IES capacity configuration. Full article

In the context of the global energy structure transformation, concentrated solar power (CSP) technology has gained significant attention. Its future trajectory is oriented towards the construction of ultra-high temperature (700–1000 °C) power plants, aiming to enhance thermoelectric conversion efficiency and economic competitiveness. Chloride molten salts, serving as a crucial heat transfer and storage medium in the third-generation CSP system, offer numerous advantages. However, they are highly corrosive to metal materials. This paper provides a comprehensive review of the corrosion behaviors of stainless steels and high-temperature alloys in molten salts. It analyzes the impacts of factors such as temperature and oxygen, and it summarizes various corrosion types, including intergranular corrosion and hot corrosion, along with their underlying mechanisms. Simultaneously, it presents an overview of the types, characteristics, impurity effects, and purification methods of molten salts used for high-temperature heat storage and heat transfer. Moreover, it explores novel technologies such as alternative molten salts, solid particles, gases, liquid metals, and the carbon dioxide Brayton cycle, as well as research directions for improving material performance, like the application of nanoparticles and surface coatings. At present, the corrosion of metal materials in high-temperature molten salts poses a significant bottleneck in the development of CSP. Future research should prioritize the development of commercial alloy materials resistant to chloride molten salt corrosion and conduct in-depth investigations into related influencing factors. This will provide essential support for the advancement of CSP technology. Full article

The liquid carbon dioxide energy storage system (LCES), as a highly flexible, long-lasting, and environmentally friendly energy storage technology, shows great potential for application in integrated energy systems. However, research on the combined cooling, heating, and power supply using LCES in integrated energy systems is still limited. In this paper, an optimized scheduling scheme for a low-carbon economic integrated energy system is proposed, coupling LCES with power-to-gas (P2G) technology and the green certificate/carbon trading mechanism. Mathematical models and constraints for each system component are developed, and an optimization scheduling model is constructed, focusing on the economic and low-carbon operation of the integrated energy microgrid system. The objective function aims to minimize total system costs. A case study based on a northern China park is conducted, with seven scenarios set for comparative optimization analysis. The results demonstrate that the use of the combined cooling, heating, and power LCES system reduces total costs by USD 2,706.85 and carbon emissions by 34.57% compared to the single-energy flow operation. These findings validate the effectiveness of the proposed model in optimizing system costs and reducing carbon emissions. Full article

Cruise ships function as a means of transport while simultaneously accommodating thousands of guests, providing a holiday experience with various entertainment options. This translates to high energy requirements for propulsion and hotel operations, typically covered by the combustion of fossil fuels. The operation of cruise vessels with fossil fuels contributes to carbon dioxide and also local harmful emissions in ports when shore power connections are not available. To enable cleaner and sustainable cruising, alternative technologies and fuels must be adopted. The present study evaluated the applicability of hydrogen fuel in combustion engines in a Meraviglia-class cruise ship. The fuel consumption of the ship was based on a real operation in Europe. This study examined how fuel energy in the form of LH₂ could be stored on the ship for a European cruise route and concludes that 3700 m³ of storage space would be needed to accommodate the liquid hydrogen. The mass of the LH₂ would only be one-third of that of fossil fuels, but the weight of the LH₂ tanks would most likely increase the total weight of the hydrogen storage. Additional new technologies and combined power production could significantly reduce the amount of LH₂ to be stored. Full article

Direct air capture (DAC) systems that capture carbon dioxide (CO₂) directly from the atmosphere are garnering considerable attention for their potential role as negative emission technologies in achieving net-zero CO₂ emission goals. Common DAC technologies are based either on liquid–solvent (L-DAC) or solid–sorbent (S-DAC) to capture CO₂. A comprehensive multi-factor comparative economic analysis of the deployment of L-DAC and S-DAC facilities across various United States (U.S.) cities is presented in this paper. The analysis considers the influence of various factors on the favorability of DAC deployment, including local climatic conditions such as temperature, humidity, and CO₂ concentrations; the availability of energy sources to power the DAC system; and costs for the transport and storage of the captured CO₂ along with the consideration of the regional market and policy drivers. The deployment analysis in over 70 continental U.S. cities shows that L-DAC and S-DAC complement each other spatially, as their performance and operational costs vary in different climates. L-DAC is more suited to the hot, humid Southeast, while S-DAC is preferrable in the colder, drier Rocky Mountain region. Strategic deployment based on regional conditions and economics is essential for promoting the commercial adoptability of DAC, which is a critical technology to meet the CO₂ reduction targets. Full article

With the requirement of energy decarbonization, natural gas (NG) and hydrogen (H₂) become increasingly important in the world’s energy landscape. The liquefaction of NG and H₂ significantly increases energy density, facilitating large-scale storage and long-distance transport. However, conventional liquefaction processes mainly adopt electricity-driven compression refrigeration technology, which generally results in high energy consumption and carbon dioxide emissions. Absorption refrigeration technology (ART) presents a promising avenue for enhancing energy efficiency and reducing emissions in both NG and H₂ liquefaction processes. Its ability to utilize industrial waste heat and renewable thermal energy sources over a large temperature range makes it particularly attractive for sustainable energy practices. This review comprehensively analyzes the progress of ART in terms of working pairs, cycle configurations, and heat and mass transfer in main components. To operate under different driven heat sources and refrigeration temperatures, working pairs exhibit a diversified development trend. The environment-friendly and high-efficiency working pairs, in which ionic liquids and deep eutectic solvents are new absorbents, exhibit promising development potential. Through the coupling of heat and mass transfer within the cycle or the addition of sub-components, cycle configurations with higher energy efficiency and a wider range of operational conditions are greatly focused. Additives, ultrasonic oscillations, and mechanical treatment of heat exchanger surfaces efficiently enhance heat and mass transfer in the absorbers and generators of ART. Notably, nanoparticle additives and ultrasonic oscillations demonstrate a synergistic enhancement effect, which could significantly improve the energy efficiency of ART. For the conventional NG and H₂ liquefaction processes, the energy-saving and carbon emission reduction potential of ART is analyzed from the perspectives of specific power consumption (SPC) and carbon dioxide emissions (CEs). The results show that ART integrated into the liquefaction processes could reduce the SPC and CE by 10~38% and 10~36% for NG liquefaction processes, and 2~24% and 5~24% for H₂ liquefaction processes. ART, which can achieve lower precooling temperatures and higher energy efficiency, shows more attractive perspectives in low carbon emissions of NG and H₂ liquefaction. Full article

Integrating carbon capture and storage (CCS) technology into an integrated energy system (IES) can reduce its carbon emissions and enhance its low-carbon performance. However, the full CCS of flue gas displays a strong coupling between lean and rich liquor as carbon dioxide liquid absorbents. Its integration into IESs with a high penetration level of renewables results in insufficient flexibility and renewable curtailment. In addition, integrating split-flow CCS of flue gas facilitates a short capture time, giving priority to renewable energy. To address these limitations, this paper develops a carbon capture, utilization, and storage (CCUS) method, into which storage tanks for lean and rich liquor and a two-stage power-to-gas (P2G) system with multiple utilizations of hydrogen including a fuel cell and a hydrogen-blended CHP unit are introduced. The CCUS is integrated into an IES to build an electricity–heat–hydrogen–gas IES. Accordingly, a deep low-carbon economic optimization strategy for this IES, which considers stepwise carbon trading, coal consumption, renewable curtailment penalties, and gas purchasing costs, is proposed. The effects of CCUS, the two-stage P2G system, and stepwise carbon trading on the performance of this IES are analyzed through a case-comparative analysis. The results show that the proposed method allows for a significant reduction in both carbon emissions and total operational costs. It outperforms the IES without CCUS with an 8.8% cost reduction and a 70.11% reduction in carbon emissions. Compared to the IES integrating full CCS, the proposed method yields reductions of 6.5% in costs and 24.7% in emissions. Furthermore, the addition of a two-stage P2G system with multiple utilizations of hydrogen further amplifies these benefits, cutting costs by 13.97% and emissions by 12.32%. In addition, integrating CCUS into IESs enables the full consumption of renewables and expands hydrogen utilization, and the renewable consumption proportion in IESs can reach 69.23%. Full article

Carbon dioxide (CO₂) is recognized as the primary cause of global warming due to its greenhouse potential. It plays a significant role in contributing to the emissions arising from a variety of anthropogenic activities, such as energy production, transportation, the construction industry, and other industrial processes. Capturing and utilizing CO₂ to mitigate its impact on the environment is, therefore, of significant importance. To do so, strategies such as net-zero strategies, deploying capture and storage technologies, and converting CO₂ into useful products have been proposed. In this review, we focused our attention on the preparation and performance of polymeric and crystalline materials for efficient CO₂ capture. More precisely, we examined MOFs, petroleum-based polymers (amine-based, polymeric ionic liquid, ionic polymer, conjugated macro/micro-cyclic polymer, and porous organic polymer) as well as bio-based polymers for CO₂ capture. In brief, the present work aims to guide the reader on the available crafted polymeric and crystalline materials offering a promising avenue towards innovative carbon dioxide capture strategy. Full article

Energy storage technology can well reduce the impact of large-scale renewable energy access to the grid, and the liquid carbon dioxide storage system has the characteristics of high energy storage density and carries out a variety of energy supply, etc. Therefore, this paper proposes an integrated energy system (IES) containing liquid carbon dioxide storage and further exploits the demand-side regulation potential on the basis of which an integrated demand response model is proposed to consider the cooling, heating, and electricity loads. On this basis, an IES optimal scheduling model with the lowest total system operating cost as the objective function is established, the Yalmip toolbox and Cplex commercial solver are used to solve the algorithms, and the optimal scheduling results are obtained for electricity, heat, and cold under four scenarios, and it is proved through comparative analyses that the model and scheduling strategy established in this paper can optimize the load profile, realize peak shaving and valley filling, and have good economic benefits. Then, by analyzing the impact of the initial pressure of the high-pressure storage tank and fluctuating electricity price on the liquid carbon dioxide energy storage system, the system model established in this paper has good stability. Finally, for the comprehensive demand response model established in this paper, the impact of the demand response of different types of loads on the economy of the system is analyzed in depth from the perspective of economic benefits. Full article