Analysis of the heat storage process of a new heat storage body structure

doi:10.19799/j.cnki.2095-4239.2022.0485

Abstract

Abstract:

A unique heat accumulator structure was created using standard refractory MgO brick as a heat storage medium to increase the heat storage capacity of solid heat accumulators in real-world engineering applications. Using thermal analysis method of non-fixed physical characteristics, the heat storage capability and temperature dispersion of such a new kind of heat accumulator structure are examined. The findings show that the temperature distribution of the conventional heat storage body possesses a substantial gradient under the desired heat storage duration, demonstrating a planar reduction in the core of the heat storage body as the center, with the overall temperature differential of 227.0 K. The temperature distribution of the new heat storage body linearly decreases along the transverse axis, and the overall temperature differential value is 107.8 K, which is 119.2 K lower than that of the conventional heat storage body. The temperature deviation rate of the monitoring points is decreased by 5.7%. Under the goal heat storage time, the grid node temperature of conventional heat storage accounts for only 8.7% at the design heat storage temperature of 873 K. In contrast, the proportion in the high-temperature area rises to 70.1%, resulting in the unequal distribution of overall temperature. The grid node temperature of the additional heat storage accounts for 60.4% at the intended heat storage temperature of 873 K. Because no substantial high-temperature segment has been formed, the overall temperature distribution is better. The actual heat storage capacity of the novel heat storage structure reaches 96% of the theoretical heat storage capacity at the target heat storage temperature, which is 16% higher than that of the conventional heat storage system. At the same heat storage capacity, the volume of the new heat storage system is only 83% of the conventional heat storage system, which can effectively increase the heat storage capacity of the heat storage system, can lower the cost of heat storage accordingly, and is conducive to market promotion.

Key words: heat storage, thermal analysis, numerical simulation, specific heat, solid thermal storage

CLC Number:

TK 513.5

Zifeng HU, Yaozu XU, Zhenyun DUAN, Xiangdong SHANG, Jingjiu XU. Analysis of the heat storage process of a new heat storage body structure[J]. Energy Storage Science and Technology, 2023, 12(1): 165-171.

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相关参数	网格划分1	网格划分2	网格划分3
传统结构蓄热体	72028	125363	185693
新型结构蓄热体	183001	316236	453596

相关参数	步长1/s	步长2/s	步长3/s
传统结构蓄热体	600	300	150
新型结构蓄热体	600	300	150

相关参数	传统结构蓄热体	新型结构蓄热体
MgO砖密度/(kg/m³)	2796	2796
蓄热体尺寸/m	1.38×1.15×1.11	1.33×1.20×1.07
理论蓄热容量/(kWh)	626.42	560.91
加热孔数量	30	54
加热孔截面尺寸/mm	97×65	φ65
总砖隙比	7.10	6.66
单孔加热功率/kW	2.09	1.04

时间/h	温度/K
时间/h	KⅠ	KⅡ	KⅢ	KⅣ	KⅤ	KⅥ
2.5	525.4	536.5	535.0	487.6	531.9	508.6
5	661.1	685.0	680.4	609.4	675.0	638.0
7.5	790.7	823.8	816.9	726.7	810.3	763.1
10	916.8	957.8	949.0	840.7	941.3	884.8

时间/h	温度/K
时间/h	K1	K2	K3	K4	K5	K6	K7
2.5	508.7	508.7	508.7	508.9	481.9	507.7	495.2
5	636.4	636.3	636.4	636.8	597.5	634.1	615.1
7.5	758.3	758.2	758.3	758.9	710.0	755.1	732.1
10	876.9	876.7	876.9	877.6	819.4	873.0	846.1