Experimental Study And Analysis On Mechanisms Of Dehumidification Enhancement For Enthalpy Wheel

In order to improve the total heat recovery efficiency of enthalpy wheel, choosing a suitable solid desiccant and coating technology is the key. Currently the desiccants applied to enthalpy wheel are mainly silica gel, molecular sieve, etc. The coating process and the mass ratio of desiccant directly impact on the performance of the entire heat exchanger. Enthalpy wheel desiccant requires fast moisture absorption and desorption, high moisture absorption and desorption rate. In this paper, one of desiccant coating technology and its impact on the total heat exchanger performance were tested and analysis.The paper analyzes the desiccant adsorption characteristics testing methods, sets up a test device to test the adsorption characteristics of silica gel, molecular sieve, etc. The test results indicate that silica gel has good adsorption characteristics, namely faster moisture absorption and desorption, higher moisture absorption and desorption rate. Specifically did research on desiccant coating process and found that the technology is not suitable to absorbent polymer and silica gel and molecular sieve works better. By using the testing methods, the adsorption characteristics of sample had been tested. Test results indicate that silica gel sample has a good adsorption curve. The surface structure of samples was scanned by electron microscope. Scanning results showed that silica gel has more developed pore structure than molecular sieve. It makes conductive for moisture absorption.In accordance with the coating technology, made a silica gel rotary wheel, its diameter is 500mm and the thickness is 200mm. Tested the total heat recovery efficiency of the rotary wheel in three different sets of head-wind conditions in the enthalpy difference lab. The test results indicate that the total heat recovery efficiency of silica gel rotary wheel is higher than that of existing molecular sieve rotary wheel by 35%. The heat and mass transfer model of enthalpy wheel was established. Analysis the impact factors to the total heat recovery efficiency such as head-wind speed, wheel thickness, the wheel rotational speed respectively. When the rotational speed, head-wind speed, wheel thickness changes unilateral, its total heat recovery efficiency first increased and then decreased. In the face of the wind speed V = 2 m·s^-1, wheel thickness L = 100 mm cases, the peak point is 30 r·min^-1; in wheel thickness L = 100 mm, speed 20 r·min^-1,its peak point is 0.8 m·s^-1; in the face of the wind speed V = 2 m·s^-1, 20r·min^-1, its peak point corresponds to the thickness of 180mm.