The isobaric energy recovery device can significantly reduce the energy consumption of the seawater reverse osmosis system by recycling the residual pressure energy of high-pressure concentrated brine.Three-cylinder v...The isobaric energy recovery device can significantly reduce the energy consumption of the seawater reverse osmosis system by recycling the residual pressure energy of high-pressure concentrated brine.Three-cylinder valve-controlled energy recovery device(TC-ERD)solves the fluid pulsation of traditional two-cylinder devices,but the use of a“liquid piston”exacerbates the mixing between brine and seawater.Herein,the evolutionary law of“liquid piston”and the relationship between volumetric mixing degree and operating conditions are explored.The results show that the“liquid piston”first axially expands and then gradually stabilizes,isolating the brine and seawater.Additionally,as long as the volume utilization ratio(U_(R))of the pressure exchange cylinder remains constant,there will not be much difference in the volumetric mixing degree after stabilization of the“liquid piston”(Vm-max)regardless of changes in the processing capacity(Q)and cycle time(T_(0)).Therefore,the equation for Vm-max with respect to the operating parameters(Q,T_(0))is derived,which can not only predict the Vm-max of the TCERD,but also provide an empirical reference for the design of other valve-controlled devices with“liquid piston”.When the Vm-max is 6%,the efficiency of the TC-ERD at design conditions(30 m^(3)·h^(-1),5.0 MPa)is 97.53%.展开更多
Compressed air energy storage(CAES)is an important technology in the development of renewable energy.The main advantages of CAES are its high energy capacity and environmental friendliness.One of the main challenges i...Compressed air energy storage(CAES)is an important technology in the development of renewable energy.The main advantages of CAES are its high energy capacity and environmental friendliness.One of the main challenges is its low energy density,meaning a natural cavern is required for air storage.High-pressure air compression can effectively solve the problem.A liquid piston gas compressor facilitates high-pressure compression,and efficient convective heat transfer can significantly reduce the compression energy consumption during air compression.In this paper,a near isothermal compression method is proposed to increase the surface area and heat exchange by using multiple tube bundles in parallel in the compression chamber in order to obtain high-pressure air using liquid-driven compression.Air compression with a compression ratio of 6.25:1 is achieved by reducing the tube diameter and increasing the parallel tube number while keeping the compression chamber cross-sectional area constant in order to obtain a high-pressure air of 5 MPa.The performances of this system are analyzed when different numbers of tubes are applied.A system compression efficiency of 93.0%and an expansion efficiency of 92.9%can be achieved when 1000 tubes are applied at a 1 minute period.A new approach is provided in this study to achieve high efficiency and high pressure compressed air energy storage.展开更多
In order to obtain the dynamic characteristics of a differential piston warm gas selfpressurization system for liquid attitude and divert propulsion system, a transient model is developed using the modular modeling me...In order to obtain the dynamic characteristics of a differential piston warm gas selfpressurization system for liquid attitude and divert propulsion system, a transient model is developed using the modular modeling method. The system includes the solid start cartridge,pressure-amplified tank with liquid monopropellant, liquid regulator, gas generator, and pipes.The one-dimensional finite-element state-variable model is applied to the pipes and the lumped parameter method is adopted for the other modules. The variations of the system operation parameters over time during the startup, steady-state, and pulsing operational processes are obtained from the transient model, and the characteristics of starting time changing with different system parameters are also analyzed. It is shown that the system startup process can be divided into three distinct processes. The starting time monotonically changes with variations of the liquid regulator parameters, first decreasing and then increasing with the mass change of the solid propellant charge of the start cartridge, initial gas cavity volume of the pressure amplified tank and initial gas cushion of the propellant tank. The starting time can be reduced to less than 1.0 s（0.68–0.75 s for the current system）. For meeting the deviation requirements of ±10% of the steady-state propellant tank pressure, the positive deviation requirement is assured by the self-locking pressure and the negative deviation can be assured within an allowable maximum propellant tank volume flowrate（1.6 times the design value for the proposed system） for downstream thrusters for a designed system. The results from the simulation are useful as a guide for further system design and testing.展开更多
为满足“双碳”目标下新型电力系统灵活调节需求,发展经济高效的储能技术势在必行,抽水蓄能耦合压缩空气储能系统(pumped hydro compressed air energy storage,PH-CAES)因其兼具抽水蓄能高效与压缩空气储能能量密度高、调节范围宽的优...为满足“双碳”目标下新型电力系统灵活调节需求,发展经济高效的储能技术势在必行,抽水蓄能耦合压缩空气储能系统(pumped hydro compressed air energy storage,PH-CAES)因其兼具抽水蓄能高效与压缩空气储能能量密度高、调节范围宽的优势而逐渐兴起。该文首先对PH-CAES的工作原理和技术特点进行了详细阐述,并与其他大规模新型物理储能技术路线进行对比分析;其次,结合PH-CAES的技术特点,梳理总结了PH-CAES电站建库选址优化、水气共容舱可靠储气和液体活塞高效运行3方面的研究现状;最后,分析了PH-CAES的未来发展趋势,从选址规划、流程优化和运行控制等方面梳理了建议关注的重点方向,以期为PH-CAES相关研究提供有益借鉴。展开更多
基金supported by the Natural Science Foundation of Fujian Province(2023J011020)the Education Department of Fujian Province/Sanming University(JAT220348/B202202)Sanming University(22YG12,PYT2202).
文摘The isobaric energy recovery device can significantly reduce the energy consumption of the seawater reverse osmosis system by recycling the residual pressure energy of high-pressure concentrated brine.Three-cylinder valve-controlled energy recovery device(TC-ERD)solves the fluid pulsation of traditional two-cylinder devices,but the use of a“liquid piston”exacerbates the mixing between brine and seawater.Herein,the evolutionary law of“liquid piston”and the relationship between volumetric mixing degree and operating conditions are explored.The results show that the“liquid piston”first axially expands and then gradually stabilizes,isolating the brine and seawater.Additionally,as long as the volume utilization ratio(U_(R))of the pressure exchange cylinder remains constant,there will not be much difference in the volumetric mixing degree after stabilization of the“liquid piston”(Vm-max)regardless of changes in the processing capacity(Q)and cycle time(T_(0)).Therefore,the equation for Vm-max with respect to the operating parameters(Q,T_(0))is derived,which can not only predict the Vm-max of the TCERD,but also provide an empirical reference for the design of other valve-controlled devices with“liquid piston”.When the Vm-max is 6%,the efficiency of the TC-ERD at design conditions(30 m^(3)·h^(-1),5.0 MPa)is 97.53%.
文摘Compressed air energy storage(CAES)is an important technology in the development of renewable energy.The main advantages of CAES are its high energy capacity and environmental friendliness.One of the main challenges is its low energy density,meaning a natural cavern is required for air storage.High-pressure air compression can effectively solve the problem.A liquid piston gas compressor facilitates high-pressure compression,and efficient convective heat transfer can significantly reduce the compression energy consumption during air compression.In this paper,a near isothermal compression method is proposed to increase the surface area and heat exchange by using multiple tube bundles in parallel in the compression chamber in order to obtain high-pressure air using liquid-driven compression.Air compression with a compression ratio of 6.25:1 is achieved by reducing the tube diameter and increasing the parallel tube number while keeping the compression chamber cross-sectional area constant in order to obtain a high-pressure air of 5 MPa.The performances of this system are analyzed when different numbers of tubes are applied.A system compression efficiency of 93.0%and an expansion efficiency of 92.9%can be achieved when 1000 tubes are applied at a 1 minute period.A new approach is provided in this study to achieve high efficiency and high pressure compressed air energy storage.
文摘In order to obtain the dynamic characteristics of a differential piston warm gas selfpressurization system for liquid attitude and divert propulsion system, a transient model is developed using the modular modeling method. The system includes the solid start cartridge,pressure-amplified tank with liquid monopropellant, liquid regulator, gas generator, and pipes.The one-dimensional finite-element state-variable model is applied to the pipes and the lumped parameter method is adopted for the other modules. The variations of the system operation parameters over time during the startup, steady-state, and pulsing operational processes are obtained from the transient model, and the characteristics of starting time changing with different system parameters are also analyzed. It is shown that the system startup process can be divided into three distinct processes. The starting time monotonically changes with variations of the liquid regulator parameters, first decreasing and then increasing with the mass change of the solid propellant charge of the start cartridge, initial gas cavity volume of the pressure amplified tank and initial gas cushion of the propellant tank. The starting time can be reduced to less than 1.0 s（0.68–0.75 s for the current system）. For meeting the deviation requirements of ±10% of the steady-state propellant tank pressure, the positive deviation requirement is assured by the self-locking pressure and the negative deviation can be assured within an allowable maximum propellant tank volume flowrate（1.6 times the design value for the proposed system） for downstream thrusters for a designed system. The results from the simulation are useful as a guide for further system design and testing.
文摘为满足“双碳”目标下新型电力系统灵活调节需求,发展经济高效的储能技术势在必行,抽水蓄能耦合压缩空气储能系统(pumped hydro compressed air energy storage,PH-CAES)因其兼具抽水蓄能高效与压缩空气储能能量密度高、调节范围宽的优势而逐渐兴起。该文首先对PH-CAES的工作原理和技术特点进行了详细阐述,并与其他大规模新型物理储能技术路线进行对比分析;其次,结合PH-CAES的技术特点,梳理总结了PH-CAES电站建库选址优化、水气共容舱可靠储气和液体活塞高效运行3方面的研究现状;最后,分析了PH-CAES的未来发展趋势,从选址规划、流程优化和运行控制等方面梳理了建议关注的重点方向,以期为PH-CAES相关研究提供有益借鉴。
