Modeling of thermal conductivity of charcoal–nitrogen adsorption beds

A knowledge of the effective thermal conductivity of an adsorption compressor bed is necessary for the design of thermal compressors of adsorption-based coolers. Three existing models have been adopted to compute the effective thermal conductivity considering the adsorbent particles to be porous bodies. Although the models are tested for an activated charcoal–nitrogen system, the calculation scheme can be used for any adsorbent adsorbate pair. Experimental isotherm data are used to calculate the equilibrium concentration of nitrogen in charcoal. This calculation scheme has been validated by experimental thermal conductivity measurements covering the range 300–400 K at 1 atm and 100–1000 mbar at 300 K. The calculation scheme based on the Luikov et al. model is found to be the most successful. An empirical correlation is proposed to describe the dependence of effective thermal conductivity on the packing density and temperature