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This study developed a novel lump activated alumina-based composite material (AACM), which composed of activated alumina, polyacrylic acid, sodium polyacrylate, and sodium alginate with a mass mixing ratio of 10:1.5:1.5:1.5. The 10:1.5:1.5:1.5 AACM had the rigid and compact structure without the problems of crack and disintegration. Moreover, due to great structure strength, air channels of 10:1.5:1.5:1.5 AACM can be made by the drilling machine, which was uncomplicated and fast, and can save the mold cost. Under the same adsorption conditions, equilibrium adsorption capacities of 10:1.5:1.5:1.5 AACM were 1.3–2.7 times higher than those of activated alumina in the range of 50–90% relative humidity, and 1.1−1.4 times better than those of a silica gel-based composite material (SGCM) in the high relative humidity (80−90% RH). The calculated results by a linear driving force model showed that 10:1.5:1.5:1.5 AACM possessed greater adsorption rate coefficients compared to activated alumina and SGCM. Moreover, the energy factor of 10:1.5:1.5:1.5 AACM was comparable to that of SGCM at the regenerative conditions of 50 °C and 15% RH, and it was 53% and 27% higher than activated alumina and SGCM, respectively, when using the return air for regeneration. Thus, the proposed AACM is competitive and flexible for extensive applications. [Display omitted] • A novel lump activated alumina-based desiccant composite material was developed. • Fabrication process was uncomplicated and fast, and can save cost. • A composite had 1.3−2.7 times adsorption capacity higher than activated alumina. • A composite can increase adsorption rate coefficients and save power consumption. [ABSTRACT FROM AUTHOR]

In this study, a desiccant air conditioning system based on a solar-powered composite desiccant bed heat exchanger has been proposed and experimentally investigated. The system consists of a composite desiccant bed heat exchanger, an evacuated tube solar water heater, cooling tower, and a direct evaporative cooling unit. The composite desiccant material is synthesized by using CaCl2 as a hygroscopic salt and floral foam as a host matrix. The system operated in two different modes, i.e., heating/humidification mode during a winter season and cooling/dehumidification mode during a summer season. During the cooling/dehumidification mode the system operated with two different dehumidification approaches. The experimental results demonstrate that the second dehumidification approach dominates over the first one. The average cooling and heating capacity of the system is 404 W and 663 W with COPth of 0.31 and 0.69 during the cooling/dehumidification mode and heating/humidification mode, respectively. [ABSTRACT FROM AUTHOR]