Dynamic performance analysis of a Carnot battery-based combined cooling, heating, and power system under variable operating conditions

doi:10.19799/j.cnki.2095-4239.2025.0511

Abstract

Abstract:

Carnot batteries are anticipated to evolve into combined cooling, heating, and power (CCHP) systems based on their thermo-electric conversion principle. When integrated with cascaded latent heat and cold storage technologies, these systems can flexibly supply electricity together with multigrade heat and cold. Given the time-varying nature of renewable energy inputs and load demands, analyzing dynamic response characteristics is essential to overcome technical barriers and support large-scale deployment. This study develops a dynamic model of a Carnot battery-based CCHP system incorporating cascaded latent heat and cold storage. The model evaluates the system's multienergy coordinated response under disturbances in electrical and heating/cooling power outputs, and examines the dynamic evolution of outlet temperatures and pressures, working fluid mass flow rates, and compressor/expander rotational speeds. Results show that cascaded latent heat and cold storage units provide strong thermal buffering, effectively smoothing outlet temperature fluctuations caused by changes in working fluid flow rate. Consequently, heating/cooling power outputs—primarily governed by working fluid flow rate—respond more rapidly than electrical power. The system also demonstrates robust resistance to multi-energy disturbances, with electrical and thermal/cooling power fluctuations being independent, thus enabling stable co-generation. Moreover, compressor/expander speed and mass flow rate are positively correlated with power input during charging: a 5% decrease in electrical input reduces them by 0.8% and 2.7%, respectively. Conversely, during discharging, they are negatively correlated with load fluctuations: a 5% reduction in load increases them by 1.4% and 4.5%, respectively. These findings provide valuable insights for the development of advanced control strategies.

Key words: Carnot battery, cascaded latent heat/cold storage, dynamic performance, combined cooling, heating, and power

CLC Number:

TK 02

Jiaxing HUANG, Yao ZHAO, Puliang DU, Peifeng SUN, Jiyu LI. Dynamic performance analysis of a Carnot battery-based combined cooling, heating, and power system under variable operating conditions[J]. Energy Storage Science and Technology, 2025, 14(11): 4245-4253.

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参数及条件	单位	值
环境温度，T_e	K	298
压缩机进口压力，p₁	kPa	105
设计压比，β	—	10.50^[12]
供电氩气质量流量，ṁ_f,e	kg/s	12.50^[12]
供热/冷氩气质量流量，ṁ_{f, hc}	kg/s	6.25^[13]
压缩机等熵效率，η_c	%	85^[12]
膨胀机等熵效率，η_e	%	95^[12]
压缩/膨胀机设计转速，n	r/min	10000^[15]
级长度，L	m	10^[13]
管中心距，W	m	3.0×10^-2[13]
管外径，d_o	m	1.9×10^-2[13]
管内径，d_i	m	1.57×10^-2[13]
总管数	—	2500

单元	级数	材料	相变温度/K	比潜热/(kJ/kg)	密度/(kg/m³)	热导率/[W/(m⋅K)]
梯级相变储热单元	1	Al-Cu(质量比67∶33)	821	351	1110	80
	2	Li₂CO₃-K₂CO₃(质量比47∶53)	757	300	1850	0.6
	3	Li₂CO₃-Na₂CO₃-K₂CO₃ (质量比32∶33∶35)	661	388	2084	1.9
	4	LiCl-LiOH(质量比51∶49)	535	485	1550	1.1
	5	LiNO₃-KCl(质量比58∶42)	433	272	2196	0.9
梯级相变储冷单元	1	Pentane	143	116	756	0.2
	2	E-114	159	107	782	0.2
	3	E-90	183	90	786	0.2
	4	SP-50	223	200	1300	0.6
	5	E-15	258	320	1060	0.5