Experimental Study on Energy and Exergy Analysis of a Counter Hollow Fiber Membrane-based Humidifier

The counter hollow fiber membrane-based humidifier is used for air humidification, which avoids the problem of liquid droplets carryover in traditional liquid humidification technology. In this study, an experimental rig was established for the hollow fiber membrane humidification system. The effects of air mass flow rate, air temperature, air relative humidity, water mass flow rate, water temperature on air humidity ratio increase, air temperature difference, power consumption per unit of humidification, humidification efficiency, energy efficiency, exergy destruction and exergy efficiency were experimentally investigated using the energy and exergy method. The results reveal the enhancement of the exergy efficiency with the increase in inlet air relative humidity, inlet air dry bulb temperature, air mass flow rate, and water mass flow rate. The results show that the humidification performance of the system is strongly influenced by the water temperature, while the humidification effect is more significant for the low temperature and low air humidity. It was found that as the relative humidity and dry bulb temperature of the air increased, the exergy destruction decreased significantly and the exergy efficiency increased. Increasing the air mass flow rate and water flow temperature resulted in an increase in both exergy destruction and exergy efficiency, while increasing the water flow rate had little effect on exergy destruction and fire efficiency. The exergy efficiency of the system ranged from 0.37 to 0.71. The maximum exergy destruction was 3.74 W, which occurred at air RHa,1=30%, air temperature Ta,1=30°C, water temperature Tw,1=28°C, and air and water flow rates of 32 kg/h and 7 kg/h, respectively. The humidification efficiency of the system ranged from 0.712 to 0.925, and the power consumption per unit of humidification ranged from 0.94 g/(h•W) to 12.50 g/(h•W).