Experimental performance comparison of adiabatic and internally-cooled membrane dehumidifiers

Humidity control of indoor space using the conventional air conditioning system is energy intensive. The liquid desiccant dehumidifier, which operates on low grade energy sources, is one of the energy efficient alternatives for humidity control. Membrane dehumidifiers avoid the desiccant carryover and hence are preferred over the packed bed dehumidifiers. However, their performance is lower due to the additional resistance in the membrane. Internal cooling is one way to improve the performance of the membrane dehumidifier and the present study experimentally investigates such a dehumidifier. The operating parameters considered are specific humidity, mass flow rate, temperature and of inlet air. The performances of the adiabatic and internally cooled dehumidifiers are presented in terms of moisture removal rate and latent effectiveness. It is found that these are higher by 60 and 50%, respectively, for the internally cooled dehumidifier.