1,720,964 research outputs found
New parametric performance maps for a novel sizing and selection methodology of a Liquid Air Energy Storage system
No full textLiquid Air Energy Storage is one of the most promising novel energy storage concept that guarantees at the same time viable capital cost, high energy density and no geographical/geological constrains. Considering the complexity of the plant, composed by three different phases (charge, discharge and storage), thermodynamic modelling could be a challenging undertaking. Making use of the strong similitude with gas turbine technology, this paper aims to deliver new generalized performance maps for Liquid Air Energy Storage system. The performance maps, validated against the experimental results of Highview Power pilot plant, have been modelled by means of a comprehensive sensitivity analysis carried out considering three macro-scenarios imposing the storage pressures and the turbomachinery performance (design/off-design conditions). By means of the performance maps, the impact of the main LAES operative parameters, as well as the effect of the cold/warm thermal energy storage utilization factor, over the key performance indicators has been assessed and analysed. The analysis shows that at design condition the higher is the value of the high grade cold thermal energy storage utilization factor, the lower is the positive impact of charge pressure over the specific consumption. For off-design condition of the main turbomachinery, the negative effect of lower isentropic efficiency of the main turbomachinery on the round trip efficiency is amplified by the choice of the charge pressure. At high value of the warm energy storage utilization factor, this negative effect can be partially offset by the higher Turbine Inlet Temperature available for the expansion process of the discharge phase
A multi-objective planning tool for the optimal supply of green hydrogen for an industrial port area decarbonization
Full text linkThis study addresses the challenge of decarbonizing highly energy-intensive Industrial Port Areas (IPA), focusing on emissions from various sources like ship traffic, warehouses, buildings, cargo handling equipment and hard-to-abate industry, typically hosted in port areas. The analysis and proposal of technological solutions and their optimal integration in the context of IPA is a topic of growing scientific interest with considerable social and economic implications. Representing the main novelties of the work, this study introduces (i) the development of a novel IPA energy and green hydrogen hub located in a tropical region (Singapore); (ii) a multi-objective optimization approach to analyse, synthesize and optimize the design and operation of the hydrogen and energy hub, with the aim of supporting decision-making for decarbonization investments. A sensitivity analysis identifies key parameters affecting optimization results, indicating that for large hydrogen demands, imported ammonia economically outperforms other green hydrogen carriers. Conversely, local hydrogen production via electrolysis becomes economically viable when the capital cost of alkaline electrolyser drops by at least 30 %. Carbon tax influences the choice of green hydrogen, but its price variation mainly impacts system operation rather than design. Fuel cells and batteries are not considered economically feasible solutions in any scenario
A review on liquid air energy storage: History, state of the art and recent developments
No full textLiquid air energy storage (LAES) represents one of the main alternatives to large-scale electrical energy storage solutions from medium to long-term period such as compressed air and pumped hydro energy storage. Indeed, characterized by one of the highest volumetric energy density (≈200 kWh/m3), LAES can overcome the geographical constraints from which the actual mature large-scale electrical energy storage technologies suffer from. LAES is based on the concept that air can be liquefied, stored, and used at a later time to produce electricity. Although the liquefaction of air has been studied for over a century, the first concept of using cryogenics as energy storage was proposed for the first time in 1977 and rediscovered only in recent times. Indeed, the need for alternative energy vectors in the energy system attracted many researchers to discover the potential of the use of cryogenic media. This has brought the realization of a first LAES pilot plant and a growing number of studies regarding LAES systems. The main drawback of this technology is the low round-trip efficiency that can be estimated around 50–60% for large-scale systems. However, due to its thermo-mechanical nature, LAES is a versatile energy storage concept that can be easily integrated with other thermal energy systems or energy sources in a wide range of applications. Most of the literature published is based on thermodynamic and economic analysis focusing on different LAES configurations. This paper provides a collection of the papers published on LAES and it classifies the various studies conducted in different categories. Future perspectives show that hybrid LAES solutions with efficient design of the waste energy recovery sections are the most promising configuration to enhance the techno-economic performance of the stand-alone system
A preliminary study on the optimal configuration and operating range of a “microgrid scale” air liquefaction plant for Liquid Air Energy Storage
No full textLiquid Air Energy Storage systems represent a sustainable solution to store energy. Although a lot of interest is dedicated to large scale systems (up to 300 tons per day), a small-scale Liquid Air Energy Storage can be used as energy storage as part of a microgrid and/or an energy distribution network. However, when scaling down the size of the system, the round trip efficiency decreases due to the low performance of the liquefaction process. In this paper a preliminary study on the optimal configuration for a microgrid scale liquefaction cycle (10 tons per 12 h) for a Liquid Air Energy Storage application is proposed in order to minimize the specific consumption. The Linde, Claude and Kapitza cycles are modelled and compared by means of a parametric analysis carried out with the software Aspen HYSYS. The results show that the two stages compression Kapitza cycle operating at 40 bar represents an optimal solution in terms of performance and cycle configuration resulting in a specific consumption of about 700 kW h/t. The analysis also shows that the implementation of a pressurized phase separator leads to a reduction of the specific consumption as high as 21% (≈550 kW h/t)
Multi-objective operational optimization of a multi-energy liquid air energy storage (LAES) in a hydrogen-based green energy hub in Singapore
No full textWith the increasing penetration of renewable energies, energy storage systems are crucial to addressing supply intermittency, reducing energy peaks and decreasing primary energy consumption and pollutant emissions. Furthermore, these systems improve the efficiency and reduce the operating costs of polygeneration plants that integrate electricity, thermal energy and cooling systems. Liquid air energy storage (LAES) has emerged as a promising technology due to its thermomechanical nature and longer lifespan compared to battery energy storage systems (BESS), as it is less affected by duty cycles. This study techno-economically analyzes the energy dispatch optimisation problem for an industrial port area (IPA) in a tropical region, using a mixed-integration linear programming approach. The performances of three different electrical energy storage technologies (i.e. BESS, hydrogen storage using alkaline electrolysers and LAES) are analysed in a capacity range of 5 MWh to 50 MWh. The results show that, at higher capacities, LAES achieves lower total costs compared to both BESS and hydrogen storage, whereas at lower capacities, LAES and BESS produce comparable economic returns. Hydrogen, while providing potential emission reductions for IPA, is not a cost-effective for electrical energy storage when using electrolysers and fuel cells integrated into the energy system. Therefore, this work highlights that LAES is a competitive and efficient energy storage option for polygeneration plants, particularly when combined with a liquid hydrogen regasification plant. The potential integration of the technology with other energy systems is further explored and discussed
Experimental and numerical characterization of sub-zero phase change materials for cold thermal energy storage
No full textLatent heat thermal energy storage systems are gaining increasing attention due to their high energy density and ability to discharge at near isothermal temperatures. A good understanding of the thermal behaviour of phase change materials (PCMs) used in these systems and therefore, a methodology for the characterisation of the phase change behaviour of storage media during charge and discharge phases is important for an optimised storage design. In this work, an experimental rig in a cylindrical shape container was designed to obtain the thermal profiles of different category of sub-zero PCMs. The experimental measurement of deionised water (ice) was first used to calibrate and validate a numerical 1-D model. Three types of sub-zero PCMs were further tested including aqueous sodium chloride, aqueous ethylene glycol and decane. The numerical results showed that aqueous alcohol had the best agreement with the experiments. In the case of paraffin and aqueous sodium chloride, a discrepancy between numerical and experimental results was found. In particular, during the melting phase, the discrepancy was due to the effect of natural convection while, during the solidification phase, it was due to the effect of supercooling. This highlights the importance of correct estimation of those effects for an accurate prediction. However, due to its simplicity, the 1-D model can be considered a valid method to approximate behavior of the different PCM and to compare the thermal profiles of different materials
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Recent trends on liquid air energy storage: A bibliometric analysis
No full textThe increasing penetration of renewable energy has led electrical energy storage systems to have a key role in balancing and increasing the efficiency of the grid. Liquid air energy storage (LAES) is a promising technology, mainly proposed for large scale applications, which uses cryogen (liquid air) as energy vector. Compared to other similar large-scale technologies such as compressed air energy storage or pumped hydroelectric energy storage, the use of liquid air as a storage medium allows a high energy density to be reached and overcomes the problem related to geological constraints. Furthermore, when integrated with high-grade waste cold/waste heat resources such as the liquefied natural gas regasification process and hot combustion gases discharged to the atmosphere, LAES has the capacity to significantly increase the round-trip efficiency. Although the first document in the literature on the topic of LAES appeared in 1974, this technology has gained the attention of many researchers around the world only in recent years, leading to a rapid increase in a scientific production and the realization of two system prototype located in the United Kingdom (UK). This study aims to report the current status of the scientific progress through a bibliometric analysis, defining the hotspots and research trends of LAES technology. The results can be used by researchers and manufacturers involved in this entering technology to understand the state of art, the trend of scientific production, the current networks of worldwide institutions, and the authors connected through the LAES. Our conclusions report useful advice for the future research, highlighting the research trend and the current gaps
Multi-objective operational optimization of a multi-energy liquid air energy storage (LAES) in a hydrogen-based green energy hub in Singapore
No full textWith the increasing penetration of renewable energies, energy storage systems are crucial to addressing supply intermittency, reducing energy peaks and decreasing primary energy consumption and pollutant emissions. Furthermore, these systems improve the efficiency and reduce the operating costs of polygeneration plants that integrate electricity, thermal energy and cooling systems. Liquid air energy storage (LAES) has emerged as a promising technology due to its thermomechanical nature and longer lifespan compared to battery energy storage systems (BESS), as it is less affected by duty cycles. This study techno-economically analyzes the energy dispatch optimisation problem for an industrial port area (IPA) in a tropical region, using a mixed-integration linear programming approach. The performances of three different electrical energy storage technologies (i.e. BESS, hydrogen storage using alkaline electrolysers and LAES) are analysed in a capacity range of 5 MWh to 50 MWh. The results show that, at higher capacities, LAES achieves lower total costs compared to both BESS and hydrogen storage, whereas at lower capacities, LAES and BESS produce comparable economic returns. Hydrogen, while providing potential emission reductions for IPA, is not a cost-effective for electrical energy storage when using electrolysers and fuel cells integrated into the energy system. Therefore, this work highlights that LAES is a competitive and efficient energy storage option for polygeneration plants, particularly when combined with a liquid hydrogen regasification plant. The potential integration of the technology with other energy systems is further explored and discussed
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