Comparison on Thermal Conductivity and Permeability of Granular and Consolidated Activated Carbon for Refrigeration

This paper focuses on the development of three types of activated carbon (AC) adsorbents, i.e. granular AC, consolidated AC with chemical binder, and consolidated AC with expanded natural graphite (ENG). Their thermal conductivity was investigated with the steady-state heat source method and the permeability was tested with nitrogen as the gas source. Results show that the thermal conductivity of granular AC with different sizes almost maintains a constant at 0.36 W·(m·K)−1, while the value modestly increases to 0.40 W·(m·K)−1 for the consolidated AC with chemical binder. The consolidated AC with ENG at the density of 600 kg·m−3 shows the best heat transfer performance and their thermal conductivity vary from 2.08 W·(m·K)−1 to 2.61 W·(m·K)−1 according to its fraction of AC. However, the granular AC and consolidated AC with chemical binder show the better permeability performance than consolidated AC with ENG binder whose permeability changes from 6.98×10−13 m2 to 5.16×10−11 m2 and the maximum occurs when the content of AC reaches 71.4% (by mass). According to the different thermal properties, the refrigeration application of three types of adsorbents is analyzed.