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Simultaneous deep dehumidification and sub-dew point cooling by combined sorption dehumidification and evaporative cooling (CoSDEC): the effect of inlet air condition.

Number: 2412

Author(s) : LAO M., MIKSIK F., THU K., MIYAZAKI T.

Summary

Heat-driven desiccant dehumidification and evaporative cooling-based technologies are prospective greener and more energy-efficient alternatives to compressor-based AC systems due to the separate handling of latent and sensible heat loads. Dew point evaporative cooling (DPEC) can effectively cool air theoretically to its dew point temperature by allowing air to sequentially flow through adjacent dry and water-laden channels. Upstream sorption dehumidification can provide a lower humidity air and hence a lower dew point for DPEC. However, as the target dew point temperature decreases, the desiccant regeneration temperature increases while sorption efficiency decreases. This study introduces Combined Sorption Dehumidification and Evaporative Cooling (CoSDEC) wherein desiccant is integrated into the dry channel of a DPEC as a single unit. In CoSDEC, air flows sequentially through adjacent desiccant-coated and water-laden channels undergoing simultaneous exothermic dehumidification and endothermic evaporation while exchanging heat which results in deep dehumidification and sub-dew point cooling. A 1200mm fabricated CoSDEC prototype employing mesoporous silica gel and regenerated at 40 oC was able to simultaneously cool and dehumidify air from 30 oC and 20 g/kg da to a minimum temperature of 13.94 oC and a minimum humidity of 4.21 g/kg da at maximum working air ratio of one. Results showed that the extent to which humidity and temperature can be reduced depends on the rate of moisture accumulation by the desiccant which is influenced by the inlet air condition as well as the regeneration condition. Nevertheless, increasing inlet air humidity and/or temperature exhibited a proportional increase in the degree of humidity reduction and/or temperature drop resulting in a greater enthalpy reduction. This study presents a more effective alternative for the deep dehumidification and sub-dew point cooling of air via CoSDEC using a more easily accessible and ubiquitous low-grade heat.

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  • Original title: Simultaneous deep dehumidification and sub-dew point cooling by combined sorption dehumidification and evaporative cooling (CoSDEC): the effect of inlet air condition.
  • Record ID : 30033142
  • Languages: English
  • Subject: Technology
  • Source: 2024 Purdue Conferences. 20th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2024/07/17

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