Thermodynamic Analysis of Adsorption-Based Atmospheric Water Harvesting using Various Adsorbents in Iraqi Conditions

Abstract

This study investigates the thermodynamic performance of various adsorbent materials used in adsorption-based atmospheric water harvesting (AWH), with a focus on their application in arid regions, such as Iraq. While significant advancements have been made in developing adsorbents capable of capturing water at low humidity levels, the lack of detailed thermodynamic analysis has hindered optimal operational conditions for these materials. The study evaluates the thermodynamic efficiencies of MOF-808, MCM-41, and COF-432, comparing their performance with other materials like MOF-801, MOF-803, and Ni2Cl2BTDD. Key findings indicate that source temperature and outlet relative humidity significantly influences system efficiency, with higher source temperatures generally improving thermal efficiency. However, lower outlet relative humidity, especially at higher temperatures, can further enhance system efficiency, emphasizing the importance of effective humidity control. Additionally, the study highlights that Iraq’s elevated ambient temperatures may exacerbate efficiency losses due to higher thermal sink temperatures, underscoring the need for adaptive design strategies. The performance of various adsorbents was found to be highly material-dependent, with certain adsorbents offering superior thermal and second-law efficiencies under specific conditions. This study offers crucial insights into optimizing adsorbent selection and system design for AWH systems, particularly in challenging climates.