Development and testing of silica gel with graphite powder composite adsorbent for cooling applications

Abstract

This research work discusses the development and testing of innovative composite adsorbents made of silica gel (SG), polyvinyl alcohol (PVA) binder and graphite powder (GP). The investigation examines the specific surface area, thermal conductivity, pore volume, adsorption, and desorption rate of the synthesized composite adsorbent. Out of the various formulations, Composite A (composed of 93 % SG, 5 % GP, and 2 % PVA) demonstrates the specific surface area of 530.37 m2/g and pore volume of 0.497 cm3/g. It is noteworthy that Composite A exhibits a 14 % improvement in thermal conductivity and a 3 % increase in desorption rate when compared to its original material, while consistently maintaining the requisite mass transfer characteristics. There is significant improvement in the thermal conductivity of the composite adsorbents with the addition of more than 5 % GP. However, in addition to this enhancement, there is a reduction in adsorption capacity. X-ray diffraction investigation indicates that the composite adsorbents are thermally stable.FESEM investigation reveals that the composite A exhibit no signs of agglomeration. The suggested composite adsorbent show superior thermophysical attributes compared to both pure and silica gel-based composites, making them promising for achieving optimal performance in adsorption cooling systems (ACS), particularly with respect to the specific cooling power (SCP) and coefficient of performance (COP).