Heat and mass transfer in consolidated reacting beds for thermochemical systems

Composite reactants of calcium chloride combined with functional carbon materials for chemical heat pumps

“…Similar results were reported for the reaction experiments of composite reactant of CaCl 2 and expanded graphite with CH 3 NH 2 [4]; when the effective thermal conductivity increased from 0.46 to 1.02 W/(m K) the output of the reactor increased by 2.5 times, but when k eff increased further to about 30 W/(m K) the output was only 1.5 times larger than that at k eff = 1.02 W/(m K). The decrease in the effect of k eff on N r at higher k eff is partly due to that the heat transfer resistance between the particles in the bed and the reactor wall becomes a dominant factor for heat transfer as the effective thermal conductivity increases.…”

“…Expanded graphite is a very bulky material, and its effective thermal conductivity can be improved remarkably by compression. For example, some researchers compressed and molded expanded graphite before impregnation of the salt solution in order to attain extremely high thermal conductivity [4,5]. In case of adsorbents like activated carbon that is insoluble in water, resin is used as a binder to bond the adsorbent with expanded graphite [6].…”

“…Two kinds of composite reactants were prepared using expanded graphite (EG) and activated carbon fiber EG + CaCl 2 /NH 3 (compressed) [4] EG + Activated carbon/CO 2 (compressed) [6] Cupper foam + Zeolite (compressed) [10] EG + CaCl 2 /NH 3 (simlply mixed) [1] EG + CaCl 2 /CH 3 NH 2 [2] Polyanilin + Zeolite [11] Aluminum hydroxide + Zeolite [12] Weight fraction of heat transfer promoter [-] (ACF). Expanded graphite is an extremely bulky material with 0.03 g/cm 3 of bulk density.…”

Heat transfer of phase change materials (PCMs) in porous materials

“…In 1992, Hoogendoom and Bart [11] reported that the low thermal conductivity of PCMs can be enhanced by embedding a metal matrix structure in them. Mauran et al [12] used a solid matrix made of graphite as a support for reactive salts; meanwhile, Tong et al [13] inserted a highporosity metal matrix into the PCM to increase heat transfer. Py et al [7] developed a supported PCM made of paraffin impregnated by capillary forces into a graphite matrix, which they found to have high stability and high thermal conductivity.…”

High-efficient thermochemical sorption refrigeration driven by low-grade thermal energy

“…Usually, chemical working pairs have the advantages of large sorption capacity and high volume cooling density over physical adsorbents. The most investigation of the thermochemical refrigeration systems is focused on the metal chlorides-ammonia sorption working pairs, and these thermochemical sorption systems have received considerable attention in recent years [4][5][6][7][8][9][10][11][12] . However, low system performance is the biggest drawback for solid sorption refrigeration machine in terms of specific cooling power (SCP) and coefficient of performance (COP), which has been still limiting the extensive application of sorption refrigeration technology.…”