Dehumidifier Inlet Air Temperature Effect
Figure 3.16 presents the effect varying the inlet air temperature from 25 to 40 °C has on the performance of the dehumidifier. Figure 3.16a demonstrates that increasing supply air temperature produces a greater air absolute humidity difference and cooling output. At a constant relative humidity, an increase in supply air temperature results in a higher inlet air vapour pressure, resulting in an increased mass transfer potential. Figure 3.16b demonstrates that increasing the inlet air temperature from 25 to 40 °C increases both the latent and enthalpy effectiveness from 39.31 and 39.94 to 52.7 and 55.2 % respectively. Figure 3.16b demonstrates that the desiccant solution outlet mass concentration is almost inversely proportional to the increase in inlet air temperature. This is because as the as the inlet air temperature increases the potential for mass transfer increases.
It is evident that over the investigated range, the desiccant dehumidifier performance is more influenced by inlet air relative humidity changes than temperature, illustrated in the greater change in latent effectiveness.