Chandrasekaran Ajay Sekar, Fix Andrew J, Warsinger David M
Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Membranes (Basel). 2022 Mar 22;12(4):348. doi: 10.3390/membranes12040348.
Traditional air conditioning systems use a significant amount of energy on dehumidification by condensing water vapor out from the air. Membrane-based air conditioning systems help overcome this problem by avoiding condensation and treating the sensible and latent loads separately, using membranes that allow water vapor transport, but not air (nitrogen and oxygen). In this work, a computational fluid dynamics (CFD) model has been developed to predict the heat and mass transfer and concentration polarization performance of a novel active membrane-based energy exchanger (AMX). The novel design is the first of its kind to integrate both vapor removal via membranes and air cooling into one device. The heat transfer results from the CFD simulations are compared with common empirical correlations for similar geometries. The performance of the AMX is studied over a broad range of operating conditions using the compared CFD model. The results show that strong tradeoffs result in optimal values for the channel length (0.6-0.8 m) and the ratio of coil diameter to channel height (~0.5). Water vapor transport is best if the flow is just past the turbulence transition around 3000-5000 Reynolds number. These trends hold over a range of conditions and dimensions.
传统的空调系统通过将空气中的水蒸气冷凝来进行除湿，这会消耗大量能源。基于膜的空调系统通过避免冷凝并分别处理显热和潜热负荷来解决这一问题，它使用的膜允许水蒸气透过，但不允许空气（氮气和氧气）透过。在这项工作中，开发了一种计算流体动力学（CFD）模型，以预测新型主动式基于膜的能量交换器（AMX）的传热传质和浓差极化性能。这种新颖的设计是同类设计中首个将通过膜去除水蒸气和空气冷却集成到一个设备中的。将CFD模拟得到的传热结果与类似几何形状的常见经验关联式进行了比较。使用该比较的CFD模型，在广泛的运行条件下研究了AMX的性能。结果表明，在通道长度（0.6 - 0.8米）和盘管直径与通道高度之比（约0.5）方面存在强烈的权衡，从而得出最佳值。当流动刚好经过3000 - 5000雷诺数左右的湍流转变时，水蒸气传输效果最佳。这些趋势在一系列条件和尺寸范围内都成立。
