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

A review on the use of calcium chloride in applied thermal engineering

“…The first school uses functional carbon materials such as EG Refs. [106,107], activated carbon [30,105] and carbon fibre [108e112] and has received remarkable contributions from the Shanghai Jiao Tong University (China). The second school, with important contributions from the Boreskov Institute of Catalysis (Russia) and its Italian partner, the Institute of Energy Transformation and Accumulation (Italy), uses silica gel [113e120], alumina [119], expanded vermiculite [121] or zeolites as host matrices [122,123].…”

“…Since there is no thermochemical heat storage system on the market yet, more research in optimization and lab scale experiments are needed. Calcium chloride impregnated into EG showed larger thermal conductivity than the pure calcium chloride depending on the compression but the thermal conductivity was not increasing with other matrix materials as activated carbon [30]. Mixing of calcium chloride with other compounds such as salt hydrates or metal oxides and impregnation of calcium chloride into matrices like zeolites, bentonites and carbon materials appears also to be a promising way in addressing above-mentioned limitations.…”

“…-A better thermal [1,16] and chemical stability [15] than other salt hydrates -A less corrosiveness than other salt hydrates [16,28] -A high latent heat of fusion (hexahydrate) [15] -A small volume change during phase transition [15] -Non-toxicity [29] -In sorption processes, it can be paired with different refrigerants (water, ammonia, methylamine, methanol, ethanol: see Fig. 1) [30], allowing various applications at various operation conditions -Low or moderate temperature operating range [31] However, this material exhibits some undesirable behaviour:…”

Waste Heat Recovery from Iron Production by Using Magnesium Oxide/Water Chemical Heat Pump as Thermal Energy Storage

“…The manufacture pellets made from pure Mg(OH)2 (diameter of pellets = 2 mm, average length of pellets = 10 mm) provide a thermal conductivity around 0.20 W m -1 K -1 . 9) Expanded graphite (EG) is a good choice as a high thermal conductive material [10][11][12] to be added into pure Mg(OH)2, which not only increases the thermal conductivity of the pure Mg(OH)2 by a factor of [4][5][6]9) but also creates a kind of carrier structure that inhibits the segregation of pure material. 13) In terms of the reactivity enhancement, the LiBr was chosen for incorporation into the pure Mg(OH)2 and EG because of its high hygroscopic properties and large negative enthalpy changes caused by dissolution into water, since the EG is an inert material.…”

Water Vapor Sorption Characteristics of Calcium Chloride-Anodized Alumina Composites

“…This property is desirable as working pair for sorption chillers. Many researchers have proposed to immobilize metal salts in porous materials such as silica gel (Aristov et al., 1996a), alumina (Sharonov and and expanded graphite (Fujioka et al, 2008) to ensure easy handling of the metal-salt particles and/or to enhance the heat and mass transfer rates in solid-sorbent beds.Aluminum is one of the most suitable materials for heat exchangers because of the high thermal conductance. If aluminum plates have the hygroscopic properties, they will be very attractive sorption materials that can be rapidly cooled and heated.…”