Performance characteristics of cross-flow membrane contactors for liquid desiccant systems
Performance characteristics of cross-flow membrane contactors for liquid desiccant systems
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DOI：
10.1016/j.apenergy.2014.12.014
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发表时间：
2015-03-01
期刊：
影响因子：
11.2
通讯作者：
Jain, Sanjeev
中科院分区：
文献类型：
--
作者：
Das, Rajat Subhra;Jain, Sanjeev
基于膜的间接接触式液体干燥剂除湿技术解决了在常规直接接触式液体干燥剂系统中观察到的液体干燥剂液滴携带的严重问题。在膜接触器中，空气和液体干燥剂流在交叉流布置的交替通道中流动，由微孔半渗透疏水膜分隔。只有水蒸气可以通过膜，但液体干燥剂不能渗透。建立了用于液体除湿器的半透膜间接接触式除湿器的二维稳态数学模型。对于给定的输入参数，该模型可以预测除湿器内部的空气和干燥剂参数以及出口参数。制作了五种不同的膜接触器，并进行了一系列实验来验证数学模型。氯化锂水溶液已被用作干燥剂。实验值与预测值的最大偏差分别为：出口空气比湿和出口空气焓值± 10%，换热效率± 15%，焓效率± 20%。温度、湿度、浓度等主要参数的分布，在接触器中，已经出现了。进行了参数分析，研究膜特性，接触器的设计，流体流量，环境条件和干燥剂浓度的接触器的性能的影响。(C)2014爱思唯尔有限公司版权所有。
Membrane based indirect contact liquid desiccant dehumidification technology subsides the serious concern of liquid desiccant droplet carryover observed in conventional direct contact liquid desiccant systems. In the membrane contactor the air and liquid desiccant streams flow in alternate channels in cross-flow arrangement, separated by micro-porous semi-permeable hydrophobic membranes. Only water vapor can pass through the membranes but liquid desiccant cannot permeate. A two-dimensional steady-state mathematical model for semipermeable membrane based indirect contactors as dehumidifiers for liquid desiccant dehumidification applications has been developed. The model can predict the air and desiccant parameters inside the dehumidifier and the outlet parameters for a given input parameters. Five different membrane contactors have been fabricated and series of experiments have been conducted to validate the mathematical model. Aqueous solution of lithium chloride has been used as desiccant. The maximum deviations between experimental and predicted values are within +/- 10% for outlet specific humidity and outlet enthalpy of air, +/- 15% deviation in dehumidification effectiveness and +/- 20% deviation in enthalpy effectiveness. The distributions of major parameters viz, temperature, humidity, concentration, etc., within the contactor have been presented. Parametric analysis has been carried out to study the effects of membrane characteristics, contactor design, fluid flow rates, ambient conditions and desiccant concentration on the performance of the contactors. (C) 2014 Elsevier Ltd. All rights reserved.