Effective thermal conductivity of expanded graphite-CaCl_2 composite adsorbent for chemical adsorption chillers

摘要

This paper presents experimental data on the thermal conductivity for three types of adsorbent, namely, pure CaCl_2 powder, simple composite adsorbent and consolidated composite adsorbent. The thermal conductivities were measured by the "hot wire method" at a fixed pressure and temperature under an ammonia atmosphere. Effective thermal conductivities of the expanded graphite-CaCl_2 · nNH_3 (n = 2, 4, 8) consolidated composite adsorbent are in the range of 7.05-9.2 W m~(-1) K~(-1), which are significant higher values than those of the powders bed of 0.3-0.4 W m~(-1) K~(-1). The obtained results show that the composite adsorbent thermal conductivity λ has a strong dependence on the bulk density, the weight fraction of expanded graphite and the ammoniated state of CaCl_2.