scholarly journals Analytical models for adiabatic compressed air energy storage (A-CAES) systems in lined tunnels

2021 ◽  
Vol 897 (1) ◽  
pp. 012008
Author(s):  
Javier Menéndez ◽  
Jorge Loredo ◽  
Laura Álvarez de Prado ◽  
Jesús M. Fernández-Oro ◽  
Antonio Bernardo-Sánchez
Keyword(s):  
Heat Transfer ◽  
Rock Mass ◽  
Energy Storage ◽  
Polymer Material ◽  
Mass Flow ◽  
Thermal Energy ◽  
Compressed Air ◽  
Concrete Lining ◽  
Compressed Air Energy Storage ◽  
Sealing Layer

Abstract Adiabatic compressed air energy storage (A-CAES) systems consist of an underground reservoir where compressed air is stored at high pressures. The ambient air is compressed by compressors located at the surface and the thermal energy is stored using thermal energy storage (TES) systems. The compressed air is stored in the subsurface reservoir (charge). Then, when the electricity is needed, the compressed air is released and expanded in gas turbines to produce electricity (discharge). In this paper, an analytical model has been developed to investigate the thermodynamic behaviour during air charge and discharge processes. Operating pressures from 4.5 to 7.5 MPa has been employed in lined tunnels in the compression and decompression stages. The model considers a 20 mm thick sealing layer, a 0.4 m thick concrete lining and a 1 m thick rock mass around the air. Air mass flow rates of 0.19 and 0.27 kg s−1 have been used in the charge processes for polymer material and steel, respectively. Finally, in the discharge processes the mass flow rate increases up to -0.38 and -0.45 kg s−1 for polymer and steel. The air temperature and pressure and the temperature and heat transfer in the sealing layer, concrete lining and rock mass have been analyzed for 100 cycles considering polymer material and steel as sealing layers. The heat transfer through the sealing layer reaches -150 and -95 W m-2 for steel and polymer, respectively. The results obtained show that the storage capacity increases when the heat transfer through the sealing layer increases.

scholarly journals Thermodynamic Analysis of Compressed Air Energy Storage (CAES) Reservoirs in Abandoned Mines Using Different Sealing Layers

2021 ◽  
Vol 11 (6) ◽  
pp. 2573
Author(s):  
Laura Álvarez de Prado ◽  
Javier Menéndez ◽  
Antonio Bernardo-Sánchez ◽  
Mónica Galdo ◽  
Jorge Loredo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Rock Mass ◽  
Energy Storage ◽  
Transfer Coefficient ◽  
Abandoned Mines ◽  
Compressed Air ◽  
Concrete Lining ◽  
The Heat Transfer Coefficient ◽  
Sealing Layer

Million cubic meters from abandoned mines worldwide could be used as subsurface reservoirs for large scale energy storage systems, such as adiabatic compressed air energy storage (A-CAES). In this paper, analytical and three-dimensional CFD numerical models have been conducted to analyze the thermodynamic performance of the A-CAES reservoirs in abandoned mines during air charging and discharging processes. Unlike other research works, in which the heat transfer coefficient is considered constant during the operation time, in the present investigation a correlation based on both unsteady Reynolds and Rayleigh numbers is employed for the heat transfer coefficient in this type of application. A tunnel with a 35 cm thick concrete lining, 200 m3 of useful volume and typical operating pressures from 5 to 8 MPa were considered. Fiber-reinforced plastic (FRP) and steel were employed as sealing layers in the simulations around the fluid. Finally, the model also considers a 2.5 m thick sandstone rock mass around the concrete lining. The results obtained show significant heat flux between the pressurized air and the sealing layer and between the sealing layer and concrete lining. However, no temperature fluctuation was observed in the rock mass. The air temperature fluctuations are reduced when steel sealing layer is employed. The thermal energy balance through the sealing layer for 30 cycles, considering air mass flow rates of 0.22 kg s−1 (charge) and −0.45 kg s−1 (discharge), reached 1056 and 907 kWh for FRP and steel, respectively. In general, good agreements between analytical and numerical simulations were obtained.

Exergy-Based Optimization of Sub- and Supercritical Thermal Energy Storage Systems

2014 ◽  
Author(s):  
Louis A. Tse ◽  
Reza Baghaei Lakeh ◽  
Richard E. Wirz ◽  
Adrienne S. Lavine
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Heat Transfer Fluid ◽  
Energy And Exergy

In this work, energy and exergy analyses are applied to a thermal energy storage system employing a storage medium in the two-phase or supercritical regime. First, a numerical model is developed to investigate the transient thermodynamic and heat transfer characteristics of the storage system by coupling conservation of energy with an equation of state to model the spatial and temporal variations in fluid properties during the entire working cycle of the TES tank. Second, parametric studies are conducted to determine the impact of key variables (such as heat transfer fluid mass flow rate and maximum storage temperature) on both energy and exergy efficiencies. The optimum heat transfer fluid mass flow rate during charging must balance exergy destroyed due to heat transfer and exergy destroyed due to pressure losses, which have competing effects. Similarly, the optimum maximum storage fluid temperature is evaluated to optimize exergetic efficiency. By incorporating exergy-based optimization alongside traditional energy analyses, the results of this study evaluate the optimal values for key parameters in the design and operation of TES systems, as well as highlight opportunities to minimize thermodynamic losses.

Compressed Air Energy Storage Flow and Power Analysis

2011 ◽  
Author(s):  
Ahmed Darwish ◽  
Robert F. Boehm
Keyword(s):  
Energy Storage ◽  
Mass Flow ◽  
Renewable Energy Sources ◽  
Time History ◽  
Compressed Air ◽  
Discharge Process ◽  
Compressed Air Energy Storage ◽  
Large Size ◽  
Underground Caverns ◽  
Charging And Discharging Processes

It is being recognized that an increase in the electricity generated from central facilities of time-varying renewable energy sources will require some means of smoothing the variations with time. While thermal storage may be appropriate for solar trough and tower plants, additional approaches for storage might prove to be beneficial for other types of generation schemes. One approach to storage that has been examined to varying degrees over the years is Compressed Air Energy Storage (CAES). Compressed air can be supplied to large size tanks or underground caverns, and later this stored air can be used to generate power to shave the peak demand of electricity or maintain nearly uniform levels of power generation. The tank discharge process is time dependent on the temperature, pressure, and mass flow rate of the air leaving. Of course, this time dependency also affects the power output of the system. In the following analysis an attempt was given to determine: 1- an analysis of the charging and discharging processes; 2- a power-time relation during the discharge process; 3- an approximation for the size required for a certain energy generated (m3/MW h) as a function of the initial air pressure; 4- a relation between the discharge area and the time to stabilize the mass flow; and 5- a supplemental heat input is examined in the discharge process to maintain nearly constant discharge power. Using a thermodynamic analysis for the system the power-time history is found.

Thermal Design and Analysis of a Solid-State Grid-Tied Thermal Energy Storage for Hybrid Compressed Air Energy Storage Systems

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Khashayar Hakamian ◽  
Kevin R. Anderson ◽  
Maryam Shafahi ◽  
Reza Baghaei Lakeh
Keyword(s):  
Energy Storage ◽  
Flow Rate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Power Plants ◽  
Power Grid ◽  
Thermal Design ◽  
Compressed Air ◽  
Compressed Air Energy Storage ◽  
New Variant

Power overgeneration by renewable sources combined with less dispatchable conventional power plants introduces the power grid to a new challenge, i.e., instability. The stability of the power grid requires constant balance between generation and demand. A well-known solution to power overgeneration is grid-scale energy storage. Compressed air energy storage (CAES) has been utilized for grid-scale energy storage for a few decades. However, conventional diabatic CAES systems are difficult and expensive to construct and maintain due to their high-pressure operating condition. Hybrid compressed air energy storage (HCAES) systems are introduced as a new variant of old CAES technology to reduce the cost of energy storage using compressed air. The HCAES system split the received power from the grid into two subsystems. A portion of the power is used to compress air, as done in conventional CAES systems. The rest of the electric power is converted to heat in a high-temperature thermal energy storage (TES) component using Joule heating. A computational approach was adopted to investigate the performance of the proposed TES system during a full charge/storage/discharge cycle. It was shown that the proposed design can be used to receive 200 kW of power from the grid for 6 h without overheating the resistive heaters. The discharge computations show that the proposed geometry of the TES, along with a control strategy for the flow rate, can provide a 74-kW microturbine of the HCAES with the minimum required temperature, i.e., 1144 K at 0.6 kg/s of air flow rate for 6 h.

Design of an Interrupted-Plate Heat Exchanger Used in a Liquid-Piston Compression Chamber for Compressed Air Energy Storage

2013 ◽  
Author(s):  
Chao Zhang ◽  
Farzad A. Shirazi ◽  
Bo Yan ◽  
Terrence W. Simon ◽  
Perry Y. Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Plate Heat Exchanger ◽  
Compressed Air ◽  
Compressed Air Energy Storage ◽  
Plate Heat ◽  
Liquid Piston ◽  
Compression Chamber

In the Compressed Air Energy Storage (CAES) approach, air is compressed to high pressure, stored, and expanded to output work when needed. The temperature of air tends to rise during compression, and the rise in the air internal energy is wasted during the later storage period as the compressed air cools back to ambient temperature. The present study focuses on designing an interrupted-plate heat exchanger used in a liquid-piston compression chamber for CAES. The exchanger features layers of thin plates stacked in an interrupted pattern. Twenty-seven exchangers featuring different combinations of shape parameters are analyzed. The exchangers are modeled as porous media. As such, for each exchanger shape, a Representative Elementary Volume (REV), which represents a unit cell of the exchanger, is developed. The flow through the REV is simulated with periodic velocity and thermal boundary conditions, using the commercial CFD software ANSYS FLUENT. Simulations of the REVs for the various exchangers characterize the various shape parameter effects on values of pressure drop and heat transfer coefficient between solid surfaces and fluid. For an experimental validation of the numerical solution, two different exchanger models made by rapid prototyping, are tested for pressure drop and heat transfer. Good agreement is found between numerical and experimental results. Nusselt number vs. Reynolds number relations are developed on the basis of pore size and on hydraulic diameter. To analyze performance of exchangers with different shapes, a simplified zero-dimensional thermodynamic model for the compression chamber with the inserted heat exchange elements is developed. This model, valuable for system optimization and control simulations, is a set of ordinary differential equations. They are solved numerically for each exchanger insert shape to determine the geometries of best compression efficiency.

scholarly journals Characteristic of a multistage reheating radial inflow in supercritical compressed air energy storage with variable operating parameters

2018 ◽  
Vol 233 (3) ◽  
pp. 397-412
Author(s):  
Hui Li ◽  
Wen Li ◽  
Xuehui Zhang ◽  
Yangli Zhu ◽  
Zhitao Zuo ◽  
...  
Keyword(s):  
Energy Storage ◽  
Mass Flow ◽  
Total Pressure ◽  
Guide Vane ◽  
Expansion Ratio ◽  
Compressed Air ◽  
Total Power ◽  
Speed Ratio ◽  
Compressed Air Energy Storage ◽  
Isentropic Efficiency

In the present study, aerodynamic performance of a four-stage reheating radial inflow turbine, which is adopted in the 1.5 MW supercritical compressed air energy storage system, is analyzed by using the method of integral numerical calculation. Results illustrate that when the inlet total pressure of the first stage is decreased, the expansion ratio of the fourth stage decreases the most. System isentropic efficiency decreases about 1% when the inlet total pressure of the first stage is changed from 7 MPa to 3 MPa, and the fourth stage’s isentropic efficiency decreases about 7%. When the rotational speed is decreased, isentropic efficiency and total power decrease gradually and isentropic efficiency changes from 90.5% at 110% speed ratio to 71.1% at 60% speed ratio. Increasing reheating temperature results to the decrease of mass flow rate and isentropic efficiency and the increase of total power. Total power increases by about 105% when the reheating temperature is changed from 60 ℃ to 520 ℃. When the guide vane opening of the first stage is increased, the expansion ratio of the first stage shows different trends compared to other stages and mass flow rates, and total power are proportional to the guide vane opening. System isentropic efficiency decreases by about 4% when the guide vane opening is adjusted from 80% to 30%.

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