Dynamic Simulations on Enhanced Heat Recovery Using Heat Exchange PCM Fluid for Solar Collector
Dynamic Simulations on Enhanced Heat Recovery Using Heat Exchange PCM Fluid for Solar Collector
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DOI：
10.3390/en16073075
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发表时间：
2023-03
期刊：
影响因子：
3.2
通讯作者：
Yawen Ren;H. Ogura
中科院分区：
文献类型：
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作者：
Yawen Ren;H. Ogura
面对碳中和目标，能源供应链应更加低碳、灵活。太阳能化学热泵（SCHP）是实现这一目标的潜在系统。我们之前的研究开发了一种基于硅油的相变材料 (PCM) 混合物作为 PCM 流体，用于增强 SCHP 太阳能集热器 (SC) 中 373 K 以上的热回收。之前对 PCM 流体进行了测试，以确认其分散性和流动特性。本研究提出了一个 3D 计算流体动力学模型，使用 PCM 流体模拟 SC 和反应器之间的闭合循环回路。使用多种流速以及 PCM 流体的 PCM 重量分数研究了 SC 中回收的热量。此外，考虑净可输送能量来评估回收热量与相对循环功率的比率。结果验证了SC在实验和模拟中回收的热量是一致的。使用 PCM 流体可提高回收的总热量。尽管显热随着流量的增加而增加，但较低的流量可以提高相变材料的熔化质量和回收的热量。当SC面积为1 m2时，最佳流量为1 L/min。此外，较高的PCM含量具有较高的潜热。另一方面，由于 PCM 热容量较低，较低含量的 PCM 会增加 SC 入口和出口之间的温差。对于 1 L/min 流量，对于 SCHP 装置，2 wt% PCM 流体比 0 wt% PCM 流体（426 kJ←403 kJ）具有更短的蓄热时间和更大的净可传输能量。
Facing the goal of carbon neutrality, energy supply chains should be more low-carbon and flexible. A solar chemical heat pump (SCHP) is a potential system for achieving this goal. Our previous studies developed a silicone-oil-based phase-change material (PCM) mixture as a PCM fluid for enhancing heat recovery above 373 K in the solar collector (SC) of the SCHP. The PCM fluid was previously tested to confirm its dispersity and flow properties. The present study proposed a 3D computational fluid dynamics model to simulate the closed circulation loop between the SC and reactor using the PCM fluid. The recovered heat in the SC was studied using several flow rates, as well as the PCM weight fraction of the PCM fluid. Furthermore, the net transportable energy is considered to evaluate the ratio of recovered heat and relative circulation power. As a result, it was verified that the recovered heat of the SC in the experiment and simulation is consistent. The total recovered heat is improved using the PCM fluid. A lower flow rate can enhance the PCM melting mass and the recovered heat although sensible heat amount increases with the flow rate. The best flow rate was 1 L/min when the SC area is 1 m2. Furthermore, the higher PCM content has higher latent heat. On the other hand, the lower content PCM can increase the temperature difference between the SC inlet and outlet because of the lower PCM heat capacity. For the 1 L/min flow rate, 2 wt% PCM fluid has shorter heat-storing time and larger net transportable energy than 0 wt% PCM fluid (426 kJ←403 kJ) for the SCHP unit.