Activated carbon fiber cloth and CaCl2 composite sorbents for a water vapor sorption cooling system

In this work, we investigated activated carbon fiber cloth (ACFC) and CaCl2 composite sorbent (CS) prepared using impregnation method. Formation mechanism of the composite was investigated. During the impregnation process, a solution of CaCl2 is concentrated inside the pores of the ACFC. The solution concentration process is described using the Polanyi potential theory and the DubinineRadushkevich equation while ignoring Ca 2+ adsorption by the surface functional groups. If the CaCl 2 content of the CS is less than 38.2%, all the CaCl2 locates inside the pores of the ACFC. The water sorption performances of the CS of different CaCl2 contents were measured using an ASAP2020M Accelerated Surface Area and Porosimetry analyzer. The CSs with a CaCl2 content of 15.2 and 22.8% exhibit a greater amount of absorbed water than the equivalent CaCl2. This is because the CaCl2 dispersed inside within pores exhibits a lower hydration pressure than the bulk CaCl2, and the ACFC contributes to the amount of water that is absorbed. However, it is likely that the hydration pressure of the dispersed CaCl2 in the CS containing the maximum possible amount of CaCl 2 does not change. Water sorption in this kind of CS can reach as high as 90% of the equilibrium water sorption amount within 2 min. The coefficient of performance for the air conditioning cycles calculated from the isosters of the CS containing the maximum CaCl2 content may reach 0.7, which is considered promising for sorption cooling. © 2013 Elsevier Ltd. All rights reserved.