Two-stage evaporative cooling system with composite activated carbon fiber dehumidification

A two-stage evaporative cooling system with composite activated carbon fiber dehumidification is proposed. After the first evaporative cooling, the high humidity air is dehumidified in the internally cooled desiccant bed, then sent to the second evaporative cooling unit for further cooling. The evaporative cooling unit adopts the fiber wet curtain as the cooling medium. In the internally cooled desiccant bed, composite activated carbon fiber (ASL) is filled, and copper tubes are arranged for cooling/heating. ASL is prepared of activated carbon fiber (ACF) impregnated with silica sol and LiCl, with an equilibrium dehumidification capacity can increase 3.1 times higher than ACF. The average dehumidification capacity of the desiccant bed reaches 5.59 g/g, and the relative humidity of the outlet air decreased to below 50% in 46 min. In the two-stage evaporative cooling system performance experiments, the supply air temperature is 3.1–4.8 °C lower than the single-stage, and the humidity ratio is 0.42–2.66 g/kg lower. The cooling capacity Qc,e, cooling efficiency ղTwo-stage, and coefficient of performance (COP) increases with increasing inlet air temperature and decreasing inlet air relative humidity, air velocity, and cooling water temperature. Qc,e, ղTwo-stage, and COP of the two-stage evaporative cooling system can reach up to 3757.5 W, 1.78, and 10.8, 808.8 W, 0.64, and 2.33 larger than these in the single-stage.