ANALYSIS OF EFFECTIVE PARAMETERS ON A ROTARY DESICCANT WHEEL PERFORMANCE

Input wet air or process air is dried in a rotary de­humidifier, using solid desiccant particles that area means to the dehumidification of indoor air. The humidity amount on the surface of the desiccant is increased during the dehumidification process and is adsorbed by a regenerat ion air stream, which is ultimately exhausted to an1bient .In this study, the effect of the Ackermann heat transfer correction factor was investigated by using mathematical modeling of a solid desiccant wheel, as well as mass, energy and moment um balances on air and wet solid particles of the desiccant for the process and regeneration of an air stream. The re­ sults indicated that the dehumidific.a.t ion rate, along\Vith the desicc.a.nt wheel is dependent on humidity ratio, air velocity and the mass aitd heat transfer from the air stream to the desiecant bed and the Ackermann correction fa.c.tor. By increasing the in­ put air relative to the humidity and temperature by more thait 50% and 95°C, the respectively, the ack­ ermann factor correets the heat transfer
coefficient by up to 4%. The comparison between the ainmmt of humidity ratio, exit aitd inlet tem perature and air stream velocity, in the adsorption part of the ro­ tary desiccant wheel showed that the velocity of the exit air strean1 from the wheel is increased, due to the variation of humidity, temperature and pressure depletion. This mathemat ical model is also capable of depicting the details of superficial humidity and the temperature of the air stream into the desicc.a.nt wheel channels in both adsorpt ion and regeneration parts, as periodic: profiles.