Experimental Investigation on Moisture Transfer of Carbon Nanotube Membranes

Abstract

With the development of society and economy, the contradiction between the increasing demand of indoor air quality and the energy saving policy of building becomes more and more obvious. Therefore, it is very important to introduce efficient energy recovery device in the fresh air system. In recent years, more and more attention has been paid to the membrane based heat exchanger due to its unique advantages. The mass transfer properties of the membrane will directly affect the heat recovery efficiency. Much research has shown that carbon nanotube (CNT) exhibits strong mass transfer capacity in many different fields. Therefore, we apply CNT-based membrane in heat exchanger for energy saving in building. In this paper, a test rig is built to investigate the mass transfer properties of the CNT-based membrane. The research contents are as follows:(1)The moisture transfer characteristics of CNT composite membranes, commercial heat exchanger membranes, commercial CNT membranes are compared;(2)The effect of inlet humidity on the moisture transfer characteristics of CNT membrane is investigated;(3)The effect of the air flow rate on the moisture transfer characteristics is investigated. Results show that the moisture transfer performance of CNT composite membranes is better than that of commercial heat exchanger membranes; The moisture transfer coefficient of CNT does not change significantly with the change of the inlet humidity and the average mass transfer coefficient of CNT is 17×10-3 m/s; The moisture transfer coefficient of the CNT increases with the increase of the air flow rate from 9.7×10-3 m/s to 14.6×10-3 m/s.