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The current research highlights the potential of using desiccant dehumidification technology with the merits of low initial energy consumptions. The system consists of desiccant (DSC) block units, dehumidification and regeneration air sources, air flow control valves, and a set of the heat exchanger. Attention was given to the DSC blocks. The blocks were made of hydrophilic polymer with honeycomb shaped. The present study focuses on the heat and mass transfer (HMT) characteristics to enhance the performance of the system. Three different process air temperatures of 20 o C, 25 o C, and 35 o C were investigated under constant regeneration air temperature of 55 o C and inlet air velocity of 0.1 kg/s. For each process air temperature, four different switching time ratios were also introduced to examine the HMT balance of the DSC blocks. The results revealed that the dehumidification capacity of the DSC system has high potential as air conditioning devices. The discrepancy of HMT found was less than 8%. Hence, the experimental methods were reliable to conduct the further experiments.

Abstract:The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (d i ) called blockage ratio (R b ) of 0.28, 0.35 and 0.42 were tested and their performance was compared to that of a longitudinal strip and plain tube under similar test flow conditions. Experiments were conducted over a wide range of flow rates, 3.35 × 10 −5 -8.33 × 10 −5 m 3 /s, which correspond to 5500 ≤ Reynolds number (Re) ≤ 14,500 in the 14.3 mm i.d. tube. The results revealed that using DWTs dramatically increased the Nusselt number (Nu) by as much as 364.3% and the friction factor (f ) by 15.5 times compared with those of a plain tube. Thermal performance (η) increased with a corresponding increase in R b . The highest thermal performance (η) obtained was 1.4. Showing a notable improvement on the thermal performance of the system, DWTs are proposed as a favorable insert device.

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