Development of thermal conductive consolidated activated carbon for adsorption refrigeration

A new type consolidated composite activated carbon (AC) was developed with a host matrix of expanded natural graphite treated with sulfuric acid (ENG-TSA). Samples with different density, different grain size of AC, and different proportion of AC were produced and thermo-physical properties were evaluated. Results show that the highest effective thermal conductivity and thermal diffusivity of consolidated composite AC were 34.2W m(-1) K-1 and 3.89 x 10(-5) m(2) s(-1), which were 150 times and 72 times higher, respectively, than ordinary granular AC. The permeability of adsorbents ranged between 1.24 x 10(-14) and 7.81 x 10(-10) m(2) m while the density ranged between 215 and 448 kg m(-3). The adsorption performance for composite AC and granular AC were evaluated by fitting experimental data with the equilibrium Dubinin-Astakhov (D-A) equations. Results show that the addition of ENG-TSA can improve the performance of adsorption refrigeration machines by increasing the concentration swing. (C) 2011 Elsevier Ltd. All rights reserved.