Experimental optimization of the cycle time and switching time of a metal organic framework adsorption desalination cycle

Abstract

The thermally driven adsorption desalination cycle has been considered a promising solution to mitigate the gap between freshwater needs and demands. Silica gel and zeolite are commonly used in the cycle however, they have low capacity. So, metal–organic framework adsorbents have been proposed as a replacement for silica gel and zeolite. Performance of the adsorption desalination cycle using metal–organic framework materials has been extensively investigated numerically with limited available experimental measurements in the open literature. In this work, a lab-scale adsorption desalination cycle using heat recovery was built using a metal organic framework (CPO-27(Ni)) as an adsorbent. Effect of the cycle time, switching time, condenser type, and cooling water temperature is assessed from the viewpoint of the cycle’s specific daily water production and gained output ratio. This investigation aims to specify the optimal cycle time and switching time. The experimental measurements identify that the optimal cycle time and switching time are 12 min and 30 s, respectively. At these conditions, the cycle produces a specific daily water production of 9.5 m3/ton/day at a gained output ratio value of 0.46. Using a coil condenser is found to be more efficient than using a finned-tube condenser. The specific daily water production decreases by 26% and the gained output ratio drops by about 22% when the cooling temperature increases from 15 to 35 °C. The present results indicate the importance of optimizing the operating conditions to achieve higher efficiency.