Dehumidifier Inlet Air Relative Humidity Effect
Figure 3.15 presents the effect varying the inlet air relative humidity from 40 to 90 % has on the performance of the dehumidifier. Figure 3.15a, demonstrates that the increase in air absolute humidity difference and cooling output is proportional to the inlet air relative humidity. As the inlet air relative humidity increases, so does the partial vapour pressure of the air, leading to a greater vapour pressure differential between the air and desiccant solution. An increase in the vapour pressure differential leads to increased mass transfer and thus a greater change in the absolute humidity of supply air, creating a larger (latent) cooling effect. Figure 3.15b demonstrates that increasing the inlet air relative humidity from 40 to 90 % increases both the latent and enthalpy effectiveness from 28.14 and 35.56 to 45.74 and 47.72 % respectively. Figure 3.15b demonstrates that the desiccant solution outlet mass concentration is inversely proportional to inlet air relative humidity.
Fig. 3.16 a, b Inlet air temperature effect on dehumidifier performance