Numerical model of a small-scale liquid-to-air membrane energy exchanger: Parametric study of membrane resistance and air side convective heat transfer coefficient
Numerical model of a small-scale liquid-to-air membrane energy exchanger: Parametric study of membrane resistance and air side convective heat transfer coefficient
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DOI：
10.1016/j.applthermaleng.2013.07.017
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发表时间：
2013-11
影响因子：
6.4
通讯作者：
D. G. Moghaddam;Ashkan Oghabi;G. Ge;R. Besant;C. Simonson
中科院分区：
文献类型：
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作者：
D. G. Moghaddam;Ashkan Oghabi;G. Ge;R. Besant;C. Simonson
小型单板液-气膜能量交换器 (LAMEE) 是一种新型膜式能量交换器，允许通过半透膜在供应空气流和盐溶液流之间进行热量和水分传递。在本文中，对小规模单面板 LAMEE 的稳态有效性进行了实验测量和数值模拟。将数值模型与夏季和冬季测试条件下的实验数据进行了比较。使用数值模型研究的参数包括膜蒸汽扩散阻力（VDR）和空气侧对流换热系数。测量了小型LAMEE 中的膜VDR，并研究了该参数对稳态有效性的影响。将膜 VDR 从 56 s/m 降低到 24 s/m 会使 LAMEE 潜在有效性增加 11%，并且正如预期的那样，它对 LAMEE 显效没有任何影响。计算了小型LAMEE气流中的强化对流换热系数，并研究了该参数对LAMEE有效性的影响。结果显示，采用 Reair= 1570 的空气筛时，LAMEE 空气通道中的对流换热系数提高了 138%，从而使 LAMEE 效率提高了 11%。最后，通过实验数据验证了修改后的数值模型在夏季试验条件下在四个不同热容量比值（Cr*=1、3、5和7）和NTU=3.8下小型LAMEE的稳态有效性。此外，将数值模型用于冬季试验条件，并将结果与实验数据进行了比较。结果表明，LAMEE在空气加热加湿和空气加热除湿测试条件下的潜在有效性和总有效性的数值模型与实验数据一致。
A small-scale single-panel liquid-to-air membrane energy exchanger (LAMEE) is a novel membrane based energy exchanger that allows heat and moisture transfer between a supply air stream and a salt solution flow through a semi-permeable membrane. In this paper, the steady-state effectiveness of the small-scale single-panel LAMEE is experimentally measured and numerically modeled. The numerical model is compared with the experimental data for summer and winter test conditions. Parameters those are investigated using the numerical model include membrane vapor diffusion resistance (VDR) and air side convective heat transfer coefficient. The membrane VDR in the small-scale LAMEE is measured and the effect of this parameter is studied for the steady-state effectiveness. Decreasing the membrane VDR from 56 s/m to 24 s/m increases the LAMEE latent effectiveness by 11%, and as expected, it doesn't have any effect on the LAMEE sensible effectiveness. Enhanced convective heat transfer coefficient in the air flow of the small-scale LAMEE is calculated, and the effect of this parameter on the LAMEE effectiveness is investigated. The results show 138% improvement in the convective heat transfer coefficient in the air channel of the LAMEE with an air screen atReair= 1570 which results in 11% improvement in the LAMEE effectiveness. Finally, the modified numerical model is validated by the experimental data for the steady-state effectiveness of the small-scale LAMEE under summer test conditions at four different values of the thermal capacity ratio (Cr* = 1, 3, 5 and 7) and NTU = 3.8. Moreover, the numerical model is used for winter test conditions, and the results are compared with the experimental data. The results show that the numerical model agrees with the experimental data for the latent and total effectiveness of the LAMEE under the air heating and humidifying and air heating and dehumidifying test conditions.