Development of novel ionic liquid-based silica gel composite adsorbents for designing high-efficiency adsorption heat pumps

Abstract

Adsorption Cooling Systems ADCS as a thermally-driven technology provide an environmentally benign solution to supply cooling needs and utilize low-temperature heat sources. Adsorbent materials are the key element in the cooling performance of the ADCS. Poor heat transfer and low packing density are the main drawbacks of the conventional adsorbents, such as silica gel, that hinder the ADCS performance. Consolidated composite adsorbents represent a great solution for this problem, in which the binder material plays a significant role in the composite adsorbent synthesis and performance. In this paper, composite adsorbent based on RD Silica Gel SG as parent material and amino acid-based Polymerized Ionic Liquid PIL as a binder material, is synthesized at different PIL percentages, namely 2%, 5%, and 10%. The thermal and adsorption characteristics of the developed composite adsorbents in addition to the theoretical cooling performance ADCS with water adsorbate have been investigated. The results show that the thermal diffusivity has been improved by a maximum value of 20% for Composite 3, while the average volumetric water uptake has been enhanced for Composite 1 by a maximum value of 20.6%, compared to the parent silica gel.