Advanced Adiabatic Compressed Air Energy Research Articles

Performance analysis and configuration method optimization of AA-CAES-based air storage tanks

To improve the performance of the compressed air energy storage (CAES) system, flow and heat transfer in different air storage tank (AST) configurations are investigated using numerical simulations after the numerical model has been experimentally validated. System performance for different AST placement methods is analyzed through numerical simulations integrated with the thermodynamic model of advanced adiabatic compressed air energy storage (AA-CAES). An in-depth study examines the impact of key system parameters on system performance with different AST configurations. Based on these analyses, the AA-CAES system with a constant volume of AST is optimized. The results indicate that horizontal placement of the AST improves heat transfer capability within the same working pressure range but results in slightly lower energy storage efficiency, achieving 64.61% compared to 65.50% for vertical placement. However, horizontal placement offers higher energy storage density, achieving 3.54 kW h/m3 under specific conditions, compared to 3.14 kW h/m3 for vertical placement. As the energy storage flow rate increases, exceeding the critical flow rate significantly improves heat transfer in vertically placed ASTs, thus narrowing the energy storage density gap between configurations. Increased turbine efficiency, additional external heat sources, and further utilization of compression heat provide more significant performance improvements for the AA-CAES with the AST placed horizontally compared to vertically. Compared to the AA-CAES with vertically placed ASTs, the configuration of the ASTs is optimized to enhance the electrical output of the AA-CAES by 76.4 MW h and reduce the input by 78.9 MW h at a storage flow rate of 0.5 kg/s.

Advanced exergo-economic analysis of an advanced adiabatic compressed air energy storage system with the modified productive structure analysis method and multi-objective optimization study

In this study, conventional and advanced exergy/exergo economic analyses of an advanced adiabatic compressed air energy storage system (AA-CAES) system with a power output of 6 MW were performed. In addition, sensitivity analysis and multi-objective optimization study of the proposed system were also carried out. For the first time in the literature, advanced exergo-economic analysis was applied to the AA-CAES system with the Modified Productive Structure Analysis (MOPSA) method, and a new parameter was introduced as a performance criterion for this method. As a result of the study, the system's exergy efficiencies were found to be 54.51 % and 77 %, respectively, according to the conventional and advanced exergy analyses of the system. According to the conventional exergy analysis, the first three system components that should be given priority are the wind turbine (WT), the regulator (REG), and the heat exchangers-3 (HE-3), respectively. According to the advanced exergy analysis, this order changes as WT, the compressor-1 (C-1), and the compressor-2 (C-2). 40 % of the system's exergy destruction and exergy destruction cost rates are avoidable endogenous. This value shows the improvement potential of the system. As a result of the multi-objective optimization study, the modified exergy efficiency was found to be 94.58 %. The average unit product-exergy destruction cost was 59.51 $/GJ; these values were 22.83 % and 1.6 % improvement, respectively, compared to the base case.

Optimal planning of electricity-gas coupled coordination hub considering large-scale energy storage

Large-scale long-duration energy storage (LDES), like compressed air energy storage (CAES) and liquid air energy storage (LAES), is promising for high-penetration renewable energy consumption in the city-scale integrated energy system (IES). Due to high installation costs and challenges in decentralized control of distributed energy storage, this paper proposes an optimal planning model for an urban electricity-gas coordination hub (UEGCH) with centralized energy storage using large-scale LDES. Firstly, the UEGCH with energy cascade utilization is designed, where process-based linearized models of advanced adiabatic compressed air energy storage (AACAES) and LAES are established to make a trade-off between solving accuracy and speed. Then, a city-scale integrated electricity and gas system (IEGS) is constructed with multiple regions considering line-packing. Finally, a multi-scenario planning method is proposed based on X-means for scenario reduction, and the global optimum is obtained through linearization. Results show that compared with traditional gas storage tank (GST) in the UEGCH, the utilization of AACAES and LAES requires as little as 7 % and 0.7 % of the construction volume with lower carbon emissions and can be cost-competitive in terms of future advancement. As for different EESs, in contrast to the energy-based energy storage (EBES) (i.e., battery (BT)), the levelized cost of energy (LCOE) of the capacity-based energy storage (CBES), which includes AACAES and LAES, can be reduced by nearly 0.1 $/kWh, bringing an annual economic benefit of $ 3 million. Besides, the discharge duration of CBES can be increased to 13 h, demonstrating the application prospect in 100 % renewable consumption and islanding operation. Compared with AACAES, LAES can reach 11.67 times the energy density, with a drop of 6.11 % in operating cost. The abilities of EBES and CBES to locally consume renewables are respectively weaker and stronger than that of power-to-gas (P2G) combined with line-packing. Meanwhile, this paper further analyzes the impacts of temperature, discharge duration, renewable penetration, energy tariff, and demand on the operation and sizing of centralized energy storage.

Optimal design and performance assessment of a proposed constant power operation mode for the constant volume discharging process of advanced adiabatic compressed air energy storage

A power operation mode of constant volume discharging process for advanced adiabatic compressed air energy storage (AA-CAES), called compensation mode (C mode), is proposed. The dynamic model of the proposed C mode discharging process is established based on the conservations of mass, momentum, and energy. The reliabilities of compressor, air tank, and air turbine are verified separately. The optimal design is carried out to reduce the power consumed by the compressor. The optimal design pressure ratio and reduced flow rate are 2.48 and 9.292 × 10−5 m·s·K0.5, respectively. This finding proves that the proposed dynamic model obeys the first and second laws of thermodynamics. The exergy distribution of the entire discharging process is studied. Results show that the two largest exergy losses occur in MT and MR. The performance of the proposed C mode is compared with that of the two other operation modes. The proposed C mode enhances the energy storage efficiency of the AA-CAES system by 14.71 %. This study provides a relatively efficient and feasible technical solution for the constant power operation of AA-CAES.

Optimal Dispatch of Integrated Energy Systems Considering Advanced Adiabatic Compressed Air Energy Storage with a High Percentage of Fluctuating Energy Consumption

Aiming at the integrated energy system (IES) of the region with a multi-energy coupling of cold, heat, and power (CHP), this research establishes the IES model with the advanced adiabatic compressed air energy storage (AA-CAES) as the energy hub. Further, to increasingly improve the system’s consumption ratio of fluctuating energy sources such as wind power, this paper designs the AA-CAES wide operating condition operation scheme based on the compressor adjustable inlet guide vanes (VIGVs) regulation technology. Finally, it is validated with a real application Case. Simulation results indicate that the operating costs of the newly modeled IES can be decreased by 20% compared to a regular integrated energy system, which demonstrates the effectiveness of AA-CAES-wide operating conditions in promoting the economic operation of integrated energy systems (IES).

Energy and exergy analysis of a novel advanced adiabatic compressed air energy storage hybridized with reverse osmosis system

Providing sustainable energy and ensuring a reliable supply of clean freshwater are two critical and interconnected challenges. This paper introduces an innovative approach that combines an advanced adiabatic compressed air energy storage system with a reverse osmosis system to enhance energy storage efficiency and freshwater production. During the charging phase, compressed air is injected into a tank filled with saltwater. Simultaneously, the high-pressure compressed air forces saltwater into the reverse osmosis modules. In the discharge phase, water is pumped into the compressed air storage tank to maintain a nearly constant tank pressure. The results demonstrate the advantages of this hybrid system over separate adiabatic compressed air energy storage and reverse osmosis systems producing the same amount of fresh water. Specifically, the proposed hybrid system achieves an 11.3 % increase in generated power during discharge and a 1.2 % improvement in round-trip efficiency. Reducing the compressed air tank capacity from 1200 to 800 m3 accentuates the hybrid system's superiority, increasing the round-trip efficiency difference between the hybrid and separated systems to 5.6 %. By selecting an appropriate compression ratio, a round-trip efficiency of 61.9 % can be achieved. Furthermore, an exergy analysis highlights the compressed air storage tank and turbines as the most exergy-destructive components of the system.

Thermodynamics Analysis of a Novel Compressed Air Energy Storage System Combined with Solid Oxide Fuel Cell–Micro Gas Turbine and Using Low-Grade Waste Heat as Heat Source

As the next generation of advanced adiabatic compressed air energy storage systems is being developed, designing a novel integrated system is essential for its successful adaptation in the various grid load demands. This study proposes a novel design framework for a hybrid energy system comprising a CAES system, gas turbine, and high-temperature solid oxide fuel cells, aiming for power generation and energy storage solutions. The overall model of the hybrid power generation system was constructed in Aspen PlusTM, and the mass balance, energy balance, and thermodynamic properties of the thermal system were simulated and analyzed. The results demonstrate that the hybrid system utilizes the functional complementarity of CAES and solid oxide fuel cells (SOFCs), resulting in the cascade utilization of energy, a flexible operation mode, and increased efficiency. The overall round-trip efficiency of the system is 63%, and the overall exergy efficiency is 67%, with a design net power output of 12.5 MW. Additionally, thermodynamic analysis shows that it is advisable to operate the system under lower ambient temperatures of 25 °C, higher compressor and turbine isentropic efficiencies of 0.9, a higher fuel utilization of 0.62, and optimal SOFC/MGT split air flow rates of 1.1 kg/s. The results of this article provide guidance for designing innovative hybrid systems and system optimization.

Analysis of compression/expansion stage on compressed air energy storage cogeneration system

Compressed Air Energy Storage (CAES) technology has risen as a promising approach to effectively store renewable energy. Optimizing the efficient cascading utilization of multi-grade heat can greatly improve the efficiency and overall system performance. Particularly, the number of compressor and expander stages is a critical factor in determining the system’s performance. In this study, we focused on the Advanced Adiabatic Compressed Air Energy Storage system with Combined Heat and Power (AA-CAES -CHP). Both economic and thermodynamic models were established for the AA-CAES-CHP system. To systematically study the effects of compression and expansion stages, the influence of 3 different compressor stages and expander stages was comprehensively analyzed under 4 operating conditions. Key findings reveal that the count of compressor and expander stages have a notable impact on the exergy losses of the AA-CAES-CHP system. As for the investment cost, the proportion of investment cost for expanders decreases when the stage numbers of compressors and expanders are the same. Furthermore, both thermodynamic and economic characteristics allow us to optimize the AA-CAES-CHP system’s performance. One of our cases demonstrates that doubling the air mass flow rate results in a doubled total energy output with a relatively modest increase (41.1%–65.1%) in the total investment cost.

Comparative evaluation of advanced adiabatic compressed gas energy storage systems

Compressed air energy storage (CAES) is a mature electrical energy storage option among different types of energy storage technologies. The positive environmental attributes of the advanced adiabatic compressed air energy storage (AA-CAES) arise from a lack of the need for a combustion chamber. Taking into account the thermodynamic properties and economic considerations, a new approach has been adopted to investigate the effect of various working fluid specifications on the overall performance of the AA-CAES system. This approach involves utilizing hydrogen and nitrogen as working fluid. The technical evaluation includes energy and exergy analysis supported by economic and parametric analysis for advanced adiabatic compressed hydrogen storage (AA-CHES) systems and in addition, an advanced adiabatic compressed nitrogen storage (AA-CNES) is also considered. The results of the thermodynamic analysis illustrate the performance measurements parameters for round-trip efficiency and exergy round-trip efficiency for AA-CHES, AA-CNES, and AA-CAES are equal to 55.05 % - 63.47 %, 54.74 % - 63.16 %, and 54.5 % - 62.91 %, respectively. It is clear that changing the working fluid improves the performance of the studied system. The payback period for AA-CNES, AA-CAES, and AA-CHES are 1.2, 1.3, and 5.4 years, respectively. Additionally, the parametric investigations reveal the influential behaviors of the design parameters on the main output of the system.

A novel constant power operation mode of constant volume expansion process for AA-CAES: Regulation strategy, dynamic simulation, and comparison

A novel operation mode of constant volume discharging process for advanced adiabatic compressed air energy storage (AA-CAES) is proposed, which achieves a constant output power by throttling and air supplementation. The dynamic model of the expansion process was developed based on the conservation of mass and energy of the open system. The reliability of the turbine and air storage tank models was verified. The results of the energy and exergy analysis of the expansion process show.

Dynamic characteristics and optimizations of the proposed combined cold and power system with integrated advanced adiabatic compressed air energy storage and double-effect compression-absorption refrigeration

A combined cold and power system with an integrated advanced adiabatic compressed air energy storage system and double-effect compression-absorption refrigeration using [mmim]DMP/CH3OH as working fluid (CACAR) was proposed. The CACAR system can use the heat generated by the compression process and the cooling capacity generated by the expansion of compressed air. The dynamic mathematical model of the CACAR system was built based on the mass conservation, energy conservation, and entropy equation of each component. The verification of the compressor, expander, air tank, and Compression absorption refrigeration (CAR) were partly implemented to validate the proposed model. The energy balance of the proposed system was confirmed. The exergy losses of each component were calculated and analyzed. The proposed model have been verified to obey the first and second laws of thermodynamics. The transient characteristics of the expansion process were simulated and discussed. Based on the sensitivity analysis results, the four key operating parameters were optimized using the multi-objective and multiparameter methods. The optimum parameter combination of γ and T37 of the refrigeration system is found to be (1.503, 342.21 Κ). The energy efficiency of the CACAR system was at least 14.97% higher than that of the AA-CAES system.

Advanced exergy and exergo-economic analyses of an advanced adiabatic compressed air energy storage system, part 2: Parametric study and optimization

In this study, parametric analysis and multi-objective optimization of the advanced adiabatic compressed air energy storage system (AA-CAES) were performed. Non-dominated Sorting Genetic Algorithm (NSGA-II) method was used in the multi-objective optimization study. In the optimization study, objective functions were determined in the conventional and advanced exergy/exergo-economic analyses concept. In the optimization study in the concept of advanced exergo-economic analyses, a new performance criterion that is not in the literature was determined and the results were confirmed by conventional exergo-economic analyses. In this study, the modified total unit product cost, which is given as the new performance criterion, is defined on the basis of avoidable feed exergy cost rate and avoidable investment cost rate. This shows the potential to be improved in the cost of the system and gives more detailed information than the total unit product cost in conventional exergo-economic analysis. As a result of the optimization study, the total unit product cost and the exergy efficiency of the system were found to be 162.9 $/day and 64.3%, respectively for the conventional exergy/exergo-economic analyses concept. For the advanced exergy/exergo-economic analyses concept, the modified total unit product cost and the modified exergy efficiency of system were found to be 103.5 $/day and 91.9 %. The exergy efficiency and the total unit product cost improved by 16.48 % and 3.55 %, respectively, with the optimization study according to the basic case of the overall system. With the parametric study, the increase in the efficiency of the wind turbine affected the exergy destruction rate more than the other system components. While the effect of the increase in the efficiency of the turbines on the exergy destruction cost rate of the system is greater than the other system components, the system component that most affects the cost rate of the system is the compressors.

Photothermal-assisted scheme design and thermodynamic analysis of advanced adiabatic compressed air energy storage system

The conventional photothermal-assisted scheme adopted by advanced adiabatic compressed air energy storage (AA-CAES) has equal stages of expanders and high-temperature reheaters, and is equipped with a regenerator to waste heat recovery, which is relatively complex and requires high solar heat supply and solar irradiance. In this paper, a novel photothermal-assisted AA-CAES (PT-AA-CAES) with a simpler structure and suitable for low solar irradiance is designed, which adopts 3-stage expansion and 2-stage high-temperature reheat. The thermodynamic model of PT-AA-CAES system is established, and a comprehensive evaluation coefficient combining exergy efficiency and energy storage density is proposed. The numerical results demonstrate that the compressor unit outlet pressure and expansion unit inlet pressure with the optimal comprehensive performance are 10 MPa and 4 MPa. Furthermore, when the solar irradiance is below 690 W/m2, 660 W/m2, and 600 W/m2, the output work, exergy efficiency, and energy storage density of the novel PT-AA-CAES system will surpass those of the conventional PT-AA-CAES system with the same solar heat consumption, and at a solar irradiance of 580 W/m2, the exceeded values are 44.3 kW h, 2.03%, and 0.15 kW h/m3, respectively. These conclusions can assist the AA-CAES system in the selection of unit pressures and photothermal-assisted scheme.

Optimal bidding strategies of advanced adiabatic compressed air energy storage based energy hub in electricity and heating markets

Integration of power and heating systems can not only improve energy efficiency but also reduce the peak generation capacity by narrowing the gap between peak and valley demands. Advanced adiabatic compressed air energy storage (AA-CAES) is a large-scale and environmental-friendly storage technology that can supply heat and power. It can be adopted as an energy hub that integrates electricity and heating systems. This paper studies the strategic behavior of an AA-CAES based energy hub in deregulated electricity and heat markets. Firstly, a heat market clearing model with elastic thermal demands is developed, and the impact of demand elasticity on the stability of the heat market is analyzed. Secondly, based on the proposed heat market model, a bi-level optimization model is established to explore the strategic bidding and scheduling of the merchant AA-CAES based energy hub in both markets. Through exploiting the weakly coupling structure of the bi-level problem, a special decomposition method is proposed to compute the market equilibrium. The optimal response of the lower-level power/heat market clearing problem is analytically expressed by multi-parametric programming techniques, where the bidding strategies are parameters. With the lower-level parameterized solution, the original complex joint optimization problem is transformed into a small-scale mixed integer quadratic program with only a few binary variables, and thus can be solved efficiently. Case studies verify the proposed model and method. Results show that the AA-CAES based energy hub/heat market is conducive to an 8.6%/22.5% reduction in the operation cost of the heat market/energy hub.

Exergy analysis and particle swarm optimization of clean energy router based on a solar‐thermal‐assisted advanced adiabatic compressed air energy storage system

AbstractThe clean Energy router based on advanced adiabatic compressed air energy storage (AA‐CAES) has the characteristics of large capacity, high efficiency and zero carbon emission which are an effective mitigation scheme for the integration of renewables and peak‐shaving and a new clean energy technology for storing energy in the world. A novel solar‐thermal‐assisted AA‐CAES (ST‐AA‐CAES) is proposed in this paper, integrating variable thermal energy storage to improve the system electric to electric (E2E) and round‐trip efficiency (RTE). The efficiency and exergy evaluation of ST‐AA‐CAES are carried out to determine the performance of ST‐AA ‐CAES. The results illustrate that E2E, RTE, and exergy efficiency can reach 56.4%, 95.5%, and 55.9%, respectively. Meanwhile, the details of exergy efficiency and destruction of each subsystem are demonstrated. Particle swarm optimization algorithm is applied to analyse the economy of optimally integrated energy systems which has the advantages of high accuracy, convenient implementation and fast convergence. The system can be applied in abundant solar energy resources area with high efficiency and multi‐energy supply capability.

Two-timescale coordinated operation of wind-advanced adiabatic compressed air energy storage system: A bilevel stochastic dynamic programming method

Renewable energy is a promising solution to address the energy crisis and environmental issues, but it comes with challenges due to its inherent volatility and limited dispatchability. Advanced adiabatic compressed air energy storage (AA-CAES) is a favorable partner for centralized renewable integration, due to its numerous benefits, such as large capacity, long lifetime, fast response capability, and zero carbon emissions. For the economic management of a wind-AACAES system, a battery-like AA-CAES dispatch model is proposed, where the charging/discharging efficiencies and capacities are dependent on the operating power and state-of-charge (SoC) to capture the part-load characteristics. A hybrid control strategy is proposed to enhance the flexibility and efficiency of the compression side under off-design conditions caused by simultaneous changes in back pressure and load. To provide dispatch and control strategies of AA-CAES, a multi-timescale optimization problem is established. The slow timescale determines the baseline output scheduling on an hourly basis to maximize total revenue, while the fast timescale updates the real-time adjustment every five minutes to minimize the penalty of tracking error. A bi-level stochastic dynamic programming (SDP) framework is formulated to incorporate the wind uncertainties and multi timescale coordination, where terminal SoCs and value functions are essential to integrate decisions across slow and fast timescales. A non-iterative parametric programming-based method is proposed to solve the slow-timescale SDP, and a simulation-based rollout algorithm is applied to extract the fast-timescale actions, which yields evident improvement over any heuristic base policy that is sequentially consistent. The numerical results demonstrate that the proposed method has a performance gap of approximately 7.1%, which outperforms the rule-based method by 32.6%. The installation of AA-CAES improves the total revenue by 11.9%. Additionally, the hybrid control strategy enhances the charging flexibility and efficiency by 30.7% and 4.3%, respectively, resulting in a 3.9% reduction in tracking deviation penalty.

Optimal Scheduling of Multi-energy System Considering Economy and Energy Conservation

In recent years, the optimal scheduling of multienergy has become the focus of the research. Against this background, this paper builds a model of a multienergy flow system of cooling, heating, and power, and advanced adiabatic compressed air energy storage (AA-CAES) is introduced to smooth wind power generation (WPG) and supply heating/cooling energy. Simulated annealing algorithm (SAA) is employed to energy-saving scheduling of the system with “exergy assessment” method. The energy-saving index and the exergy efficiency are compared in different cases. SAA is compared with the particle swarm optimization (PSO) algorithm in solving the optimal scheduling strategy. The cooling, heating, and power demands of an industrial park and WPG in typical days are employed to the simulation. The scheduling results of exergy input of SAA are far less than those of PSO in typical days of different seasons. The multienergy system without AA-CAES is also modeled, and energy-saving economic scheduling is carried out. The exergy efficiency of the system with AA-CAES is between 38% and 58% while the exergy efficiency of the system without AA-CAES is merely between 27% and 48%.

Analysis of Voltage Control Strategies for DC Microgrid with Multiple Types of Energy Storage Systems

Direct-current (DC) microgrids have gained worldwide attention in recent decades due to their high system efficiency and simple control. In a self-sufficient energy system, voltage control is an important key to dealing with upcoming challenges of renewable energy integration into DC microgrids, and thus energy storage systems (ESSs) are often employed to suppress the power fluctuation and ensure the voltage stability. In this paper, the performances of three voltage control strategies for DC microgrids are compared, including the proportion integration (PI) control, the fuzzy PI control and particle swarm optimization (PSO) PI control. Particularly, two kinds of ESSs including battery and advanced adiabatic compressed air energy storage (AA-CAES) with different operational characteristics are installed in the microgrid, and their impacts on voltage control are investigated. The control performances are comprehensively compared under different control schemes, various scenarios of renewable energy fluctuations, participation in the control of the two ESSs or not, and different fault conditions. Additionally, the dynamic performances of the ESSs are exhibited. The results verify the validity of the control schemes and the feasibility of the configuration of the ESSs into the DC microgrid.

Economic dispatch of CAES in an integrated energy system with cooling, heating, and electricity supplies

AbstractFlexible combined cooling, heating, and power (CCHP) systems are effective in integrating wind sources. As an attractive, clean, and large‐scale energy storage technique, the advanced adiabatic compressed air energy storage (AA‐CAES) can store and generate both electricity and heating, and also provide cooling during expansion under certain conditions. Although AA‐CAES has immense potential in multi‐energy supply systems, CCHP dispatch with AA‐CAES and wind power generation (WPG) is yet to be systematically studied. In this study, the economic dispatch of an AA‐CAES system equipped with WPG is addressed. The AA‐CAES system is comprehensively modelled by considering its thermal characteristics, air‐temperature changes due to heating exchange, air storage constraint, and other factors, particularly the heat supply to the air for expansion, which is a key factor that influences the cooling supply. Subsequently, the cooling, heating, and power of the AA‐CAES system are dispatched to minimise the operating cost under different supply modes. In conclusion, the proposed method is demonstrated using an integrated energy system in an industrial park, and the operation cost of the AA‐CAES system is minimised. The numerical results demonstrate that the participation of AA‐CAES in CCHP dispatch can curtail WPG and reduce operation costs. The economics of the different supply modes of AA‐CAES are also discussed.

Energy and Exergy Efficiency Analysis of Advanced Adiabatic Compressed Air Energy Storage Based Trigeneration Energy Hub

Energy and Exergy Efficiency Analysis of Advanced Adiabatic Compressed Air Energy Storage Based Trigeneration Energy Hub