Performance Analysis of Two-Stage Solid Desiccant Densely Coated Heat Exchangers

Kun-Ying Li, Win-Jet Luo, Bo-Yi Tsai and Yean- Der Kuan
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Kun-Ying Li: Graduate Institute of Precision Manufacturing, National Chin-Yi University of Technology, Taichung 41170, Taiwan
Win-Jet Luo: Graduate Institute of Precision Manufacturing, National Chin-Yi University of Technology, Taichung 41170, Taiwan
Bo-Yi Tsai: Department of Refrigeration, Air Conditioning and Energy Engineering, National Chin-Yi University of Technology, Taichung 41170, Taiwan
Yean- Der Kuan: Department of Refrigeration, Air Conditioning and Energy Engineering, National Chin-Yi University of Technology, Taichung 41170, Taiwan

Sustainability, 2020, vol. 12, issue 18, 1-19

Abstract: In this study, silica gel and sodium polyacrylate desiccants are coated onto a finned tube heat exchanger (Desiccant Coating Heat Exchanger, DCHE), which can absorb the vapor in the process air for dehumidification. In the experiments, the desiccant is coated on fins using the dense coating method, which causes the fixed fin area to be coated with greater amounts of desiccants for a better dehumidification performance. This study discusses the dehumidification performances of a single stage DCHE and two-stage DCHEs in series under different relative humidity conditions of the inlet process air and different regeneration water temperatures. The results show that the thermal coefficient of performance ( COP th ) of the DCHEs for the two desiccants prepared by the dense coating method is better than that of DCHEs with the general immersing coating method by a factor of 2–2.4. The two-stage DCHEs in series have a lower supply humidity ratio than a single stage DCHE at different inlet humidity levels, and they can be used in the industry when a special low humidity manufacturing process is required. The overall dehumidifying capacities of two-stage series-connected DCHEs at regeneration temperatures of 50 °C and 70 °C are approximately twice as high as those of a single stage DCHE. The COP th value of a single stage or two stages increases with an increase in the inlet humidity of the process air. The COP th values of the sodium polyacrylate single stage and two-stage DCHEs are 1–1.3 times greater than those of the silica gel single stage and two-stage DCHEs at a high inlet air humidity. Finally, the effects of different regeneration water temperatures on the performance of DCHEs are investigated. With an increase in the regeneration water temperature, the COP th value, dehumidifying capacity and regeneration capacity of single stage or two-stage DCHEs increase as well.

Keywords: dehumidification; dense coating method; solid desiccant; thermal coefficient of performance; two-stage DCHE (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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