Investigation on activated carbon-sodium polyacrylate coated aluminum sheets for desiccant coated heat exchanger

Adsorption and desorption properties of desiccants are of key significances to the dehumidification performance of a compact dehumidification component named desiccant coated heat exchanger. This work developed novel activated carbon (AC) sodium polyacrylate (PAAS) composite coated aluminum sheets with high adsorption property and good desorption ability. Adsorption and desorption properties of AC-PAAS coated aluminum sheets were investigated under different air conditions. Cyclic adsorption desorption features with internal-cooling/heating were conducted. Results showed that composite coated aluminum sheets had nearly 2-3 times higher water uptake than an AC coated sample in the range of medium-to high-relative humidity (60%-90% RH). More than 95% of adsorbed water in composite samples was released at 70 degrees C & 20% RH, and 86% was still desorbed when the air temperature was decreased to 40 degrees C. Adsorption capacities and rate coefficients of composite samples with internal cooling could be 2.3 and 1.5 times higher than those without. This paper provides a way to develop composite desiccants with high cyclic water uptake performance in the fields of adsorption cooling, solid desiccant air-conditioning and atmospheric water harvesting. (C) 2022 Elsevier Ltd. All rights reserved.