Variable-operating-condition operational characteristics of liquid carbon dioxide energy storage systems

doi:10.19799/j.cnki.2095-4239.2025.0050

Abstract

Abstract:

Energy storage is a critical technology for the large-scale usage of renewable energy. Liquid carbon dioxide (CO₂) energy storage systems are recognized as promising large-scale long-duration energy storage technology owing to their high energy density, compact equipment, and enhanced safety. This study establishes a variable-operating-condition model of liquid CO₂ energy storage systems to elucidate the dynamic operational characteristics and the impacts of key parameters, including initial pressures of low- and high-pressure tanks, compressor efficiency, expander efficiency, and ambient temperature, on system performance under varying operating conditions. The analysis reveals the distribution of exergy destruction, cold storage units (36.53%), compressors (24.63%), and expanders (19.58%) are the primary sources of exergy destruction. Under typical operating conditions, the high-pressure tank of the system increased from 8 MPa to 14.5 MPa, with the corresponding temperature rise from 298.15 K to 307.32 K. In contrast, the low-pressure tank pressure decreased from 0.6 to 0.59 MPa, with the temperature decreased from 220 K to 219.85 K. In addition, the proposed system achieves a round-trip efficiency of 63.14%, which is 7.2% lower than the steady-state assumptions, with an energy density of 0.9237 kWh/m³—only 3.9% of the steady-state value, due to the exclusion of unused working fluid in steady-state models. These findings provide valuable insights for the optimization design and practical application of CO₂ energy storage systems.

Key words: carbon dioxide energy storage, energy storage system, variable-operating-condition operation, roundtrip efficiency, energy density

CLC Number:

TK 02

Yuan LI, Mingzhi ZHAO, Yujie XU, Jie CAI. Variable-operating-condition operational characteristics of liquid carbon dioxide energy storage systems[J]. Energy Storage Science and Technology, 2025, 14(7): 2761-2771.

Figures/Tables 13

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Table 1

Table 2

Fig. 5

Table 3

Fig. 6

Table 4

Fig. 7

Fig. 8

Fig. 9

References 22

[1]	SONG C F, LIU Q L, JI N, et al. Alternative pathways for efficient CO₂ capture by hybrid processes—A review[J]. Renewable and Sustainable Energy Reviews, 2018, 82: 215-231. DOI: 10.1016/j.rser.2017.09.040.
[2]	WEI Y M, WANG J W, CHEN T Q, et al. Frontiers of low-carbon technologies: Results from bibliographic coupling with sliding window[J]. Journal of Cleaner Production, 2018, 190: 422-431. DOI: 10.1016/j.jclepro.2018.04.170.
[3]	李琛, 董诗婕. 聚焦美丽中国建设减污降碳绿色转型[J]. 中国水泥, 2024(3): 14-17.
	LI C, DONG S J. Focus on beautiful China and build a green transformation to reduce pollution and carbon[J]. China Cement, 2024(3): 14-17.
[4]	LI H C, DING R C, SU W, et al. A comprehensive performance comparison between compressed air energy storage and compressed carbon dioxide energy storage[J]. Energy Conversion and Management, 2024, 319: 118972. DOI: 10.1016/j.enconman. 2024.118972.
[5]	李玉平. 压缩二氧化碳储能系统的热力学性能分析[D]. 北京: 华北电力大学, 2018.
	LI Y P. Thermal performance analysis of the compressed carbon dioxide energy storage system[D]. Beijing: North China Electric Power University, 2018.
[6]	WAN Y K, WU C, LIU Y, et al. A technical feasibility study of a liquid carbon dioxide energy storage system: Integrated component design and off-design performance analysis[J]. Applied Energy, 2023, 350: 121797. DOI: 10.1016/j.apenergy. 2023.121797.
[7]	ZHAO P, XU W P, ZHANG S Q, et al. Components design and performance analysis of a novel compressed carbon dioxide energy storage system: A pathway towards realizability[J]. Energy Conversion and Management, 2021, 229: 113679. DOI: 10.1016/j.enconman.2020.113679.
[8]	XU M J, ZHAO P, HUO Y W, et al. Thermodynamic analysis of a novel liquid carbon dioxide energy storage system and comparison to a liquid air energy storage system[J]. Journal of Cleaner Production, 2020, 242: 118437. DOI: 10.1016/j.jclepro. 2019.118437.
[9]	HAO J H, ZHENG P Y, LI Y N, et al. Study on the operational feasibility domain of combined heat and power generation system based on compressed carbon dioxide energy storage[J]. Energy, 2024, 291: 130122. DOI: 10.1016/j.energy.2023.130122.
[10]	FU H L, SHI J, YUAN J Q, et al. Thermodynamic analysis of photothermal-assisted liquid compressed CO₂ energy storage system hybrid with closed-cycle drying[J]. Journal of Energy Storage, 2023, 66: 107415. DOI: 10.1016/j.est.2023.107415.
[11]	TANG D, LI Y, LIU Y J, et al. Factors affecting compressed carbon dioxide energy storage system in deep aquifers[J]. Bulletin of Engineering Geology and the Environment, 2024, 83(10): 407. DOI: 10.1007/s10064-024-03887-4.
[12]	LIU Z, LIU X, ZHANG W F, et al. Thermodynamic analysis on the feasibility of a liquid energy storage system using CO₂-based mixture as the working fluid[J]. Energy, 2022, 238: 121759. DOI: 10.1016/j.energy.2021.121759.
[13]	DENG Y Y, WANG J F, CAO Y, et al. Technical and economic evaluation of a novel liquid CO₂ energy storage-based combined cooling, heating, and power system characterized by direct refrigeration with phase change[J]. Applied Thermal Engineering, 2023, 230: 120833. DOI: 10.1016/j.applthermaleng.2023.120833.
[14]	MA H Y, LIU Z. Preliminary thermodynamic analysis of a carbon dioxide binary mixture cycled energy storage system with low pressure stores[J]. Energy, 2022, 246: 123346. DOI: 10.1016/j.energy.2022.123346.
[15]	XU W P, ZHAO P, WANG J F, et al. Comprehensive thermo-economic analysis of an isobaric compressed CO₂ energy storage system: Improvement of the thermodynamic pathway[J]. Energy Conversion and Management, 2024, 322: 119088. DOI: 10.1016/j.enconman.2024.119088.
[16]	BARTELA Ł, SKOREK-OSIKOWSKA A, DYKAS S, et al. Thermodynamic and economic assessment of compressed carbon dioxide energy storage systems using a post-mining underground infrastructure[J]. Energy Conversion and Management, 2021, 241: 114297. DOI: 10.1016/j.enconman. 2021.114297.
[17]	KIM Y M, SHIN D G, FAVRAT D. Operating characteristics of constant-pressure compressed air energy storage (CAES) system combined with pumped hydro storage based on energy and exergy analysis[J]. Energy, 2011, 36(10): 6220-6233. DOI: 10.1016/j.energy.2011.07.040.
[18]	NIELSEN L, LEITHNER R. Dynamic simulation of an innovative compressed air energy storage plant-Detailed modelling of the storage cavern[J]. Wseas Transactions on Power Systems, 2009, 4(7/9): 253-263.
[19]	AHMAD M, OSCH M B, BUIT L, et al. Study of the thermohydraulics of CO₂ discharge from a high pressure reservoir[J]. International Journal of Greenhouse Gas Control, 2013, 19: 63-73. DOI: 10.1016/j.ijggc.2013.08.004.
[20]	张娜, 林汝谋, 蔡睿贤. 压气机特性通用数学表达式[J]. 工程热物理学报, 1996, 17(1): 21-24.
	ZHANG N, LIN R M, CAI R X. General formulas for axial compressor performance estimation[J]. Journal of Engineering Thermophysics, 1996, 17(1): 21-24.
[21]	ZHAO M, ZHU Y, HU D, et al. Off-design performance of supercritical compressed carbon dioxide energy storage system[A/OL]. Volume 42: Energy Transitions toward Carbon Neutrality: Part V, 2024[2025-02-26]. https://www.energy-proceedings.org/ p=10997. DOI:10.46855/energy-proceedings-10997.
[22]	卢韶光, 林汝谋. 燃气透平稳态全工况特性通用模型[J]. 工程热物理学报, 1996, 17(4): 404-407.
	LU S G, LIN R M. Gas turbine steady-state design and off-design characteristic general model[J]. Journal of Engineering Thermophysics, 1996, 17(4): 404-407.

参数	数值	参数	数值
低压罐压力/MPa	0.6	高压罐压力/MPa	8
节流阀出口压力/MPa	0.52	高压罐温度/℃	25
低压罐温度/℃	-53.15	膨胀机效率/%	85
储冷罐温度/℃	-29	膨胀机级数	3
外界冷源温度/℃	-58.15	压缩机级数	3
压缩机设计点效率/%	85	膨胀机设计点效率/%	88

参数	变工况模拟	稳态模拟
质量流量/(kg/s)	203.4~220.9	203.4
低压罐温度/K	220~219.85	220
低压罐压力/MPa	0.6~0.59	0.6
高压罐温度/K	298.15~307.32	298.15
高压罐压力/MPa	8~14.5	8
能量密度/(kWh/m³)	0.9237	23.16
往返效率/%	63.14	70.35

流股	工质	储能过程初始时刻				储能过程终止时刻
流股	工质	压力P/MPa	温度T/K	焓h/(kJ/kg)	熵S/[kJ/(kg·K)]	压力P/MPa	温度T/K	焓h/(kJ/kg)	熵S/[kJ/(kg·K)]
1	CO₂	0.6	220	86.72	0.551	0.59	219.8	86.45	0.550
2	CO₂	0.52	216.7	86.72	0.522	0.52	216.7	86.45	0.522
3	CO₂	0.52	221.6	434.97	2.159	0.52	221.7	434.97	2.159
4	CO₂	0.52	298	501.87	2.418	0.52	298	501.87	2.418
5	CO₂	1.293	374.9	557.10	2.418	1.574	392.7	570.48	2.418
6	CO₂	1.293	303	498.72	2.243	1.574	303	495.87	2.199
7	CO₂	3.217	381.7	552.60	2.243	4.769	400.6	561.74	2.199
8	CO₂	3.217	303	477.36	2.019	4.769	303	455.19	1.887
9	CO₂	8	383	525.09	2.019	14.5	401	507.64	1.887
10	CO₂	8	303	283.26	1.269	14.5	303	260.55	1.167
11	CO₂	14.5	307.8	271.31	1.202	8	298	263.13	2.036
12	CO₂	14.5	383	485.23	1.829	8	383	532.92	2.039
13	CO₂	5	300.3	446.33	1.829	3.37	318	493.64	2.039
14	CO₂	5	381.7	551.66	2.163	3.37	381.7	561.27	2.258
15	CO₂	1.726	307.8	499.53	2.163	1.421	322.9	516.38	2.258
16	CO₂	1.726	374.2	563.23	2.383	1.421	374.2	565.37	2.423
17	CO₂	0.595	306.6	508.91	2.383	0.6	318.8	519.59	2.423
18	CO₂	0.595	298	501.24	2.391	0.6	298	501.24	2.389
19	CO₂	0.595	231.7	442.41	2.168	0.6	231.7	442.33	2.166
20	CO₂	0.595	220	431.42	2.12	0.6	220	86.72	2.084
21	CH₄	0.2	254.1	812.41	5.969	0.2	254.1	812.41	5.969
22	CH₄	0.2	226.7	753.47	5.725	0.2	226.7	753.47	5.725
23	H₂O	0.4	298	104.57	0.365	0.4	298	104.57	0.365
24	H₂O	0.4	369.9	405.7	1.270	0.4	387.7	480.7	1.468
25	H₂O	0.4	298	104.57	0.365	0.4	298	104.57	0.365
26	H₂O	0.4	376.7	434.3	1.347	0.4	395.6	514.5	1.555
27	H₂O	0.4	298	104.57	0.365	0.4	298	104.57	0.365
28	H₂O	0.4	378.6	442.5	1.368	0.4	396.4	517.8	1.563
29	H₂O	0.4	388.0	482	1.472	0.4	388.0	482	1.472
30	H₂O	0.4	312.3	164.4	0.561	0.4	303.1	126.0	0.437
31	H₂O	0.4	386.7	476.5	1.457	0.4	386.7	476.5	1.457
32	H₂O	0.4	305.2	130.6	1.352	0.4	323.8	204	2.092
33	H₂O	0.4	379.2	444.73	1.375	0.4	379.2	444.73	1.375
34	H₂O	0.4	312.9	568	1.667	0.4	327.9	764	2.293
35	CH₄	0.2	226.3	753.5	5.724	0.2	226.3	753.5	5.724
36	CH₄	0.2	293.2	897.8	6.28	0.2	293.2	897.8	6.28

序号	变化参数	范围
1	低压罐初始压力/MPa	0.6~4
2	高压罐初始压力/MPa	8~14.5
3	压缩机效率/%	70~95
4	膨胀机效率/%	70~95
5	环境温度/K	288~303