| dc.rights.license | CC0 | en_US |
| dc.contributor.author | D'ANS, Pierre | |
| dc.contributor.author | HOHENAUER, Wolfgang | |
| dc.contributor.author | COURBON, Émilie | |
| dc.contributor.author | FRÈRE, Marc | |
| dc.contributor.author | DEGREZ, Marc | |
| dc.contributor.author | DESCY, Gilbert | |
| dc.date.accessioned | 2024-12-09T14:57:23Z | |
| dc.date.available | 2024-12-09T14:57:23Z | |
| dc.date.issued | 2014 | |
| dc.identifier.uri | https://luck.synhera.be/handle/123456789/2893 | |
| dc.description.abstract | D'Ans Pierre, et al., Monitoring of thermal properties of a composite material used in thermochemical heat storage, Eurotherm Seminar, Lérida 2014 | en_US |
| dc.description.abstracten | Thermochemical heat storage can be obtained using bromides or chlorides and the reversible water vapor sorption on them. These hygroscopic salts have sometimes such a high affinity for water that they suffer from spontaneous deliquescence, leading to an irreversible behavior and further degradation of their mass transport properties (i.e. water cannot migrate inside the bed within acceptable time spans). To address this problem, composite materials consisting of salt distributed inside a porous matrix were developed, but questions arise regarding their use in real-life conditions, especially concerning their thermal behavior. In this work, a protocol was proposed to assess the thermal conductivity of such a composite, when it is exposed to temperature or moisture transients. The device consists of a climate chamber with controlled temperature and moisture, wherein a balance and a vessel containing the solid bulk material were introduced. A probe measuring thermal conductivity was set inside the material and connected to a laptop to collect the data. The balance that was also exposed to the chamber atmosphere, allowed to control the occurring phenomena, and to correlate thermal conductivity variations with sorption properties and states of hydration. The material was exposed to two thermochemical cycles, at water partial pressures of 12.5 and 17 mbar. Each cycle began with hydration at 35°C, which was maintained until mass became stable. Then, temperature was increased stepwise to 50, 60, 70 and 80°C, that are realistic conditions for thermochemical heat storage. Mass and thermal conductivity were monitored as a function of time. In parallel, thermal conductivity measurements were made in dry conditions. With increasing temperature, water is desorbed and mass decreases. Because of a superposition of the thermal conductivities of the constituents and thermal convection effects, thermal conductivity apparently increases at the beginning of this process (apparent thermal conductivity: app.). It converges to the new “equilibrium value” in the course of time. Phenomenologically this behavior can be explained by the fact that during transient (typically 1-2 days), desorbed water is entrapped inside the bed before escaping. Once water is released, the apparent conductivity app. decreases to the conductivity value. Measured conductivity data at equilibrium are in a range of ~0.155 Wm- 1K-1 at 35°C and 0.14 Wm-1K-1 at 80°C in “wet” conditions. In dry conditions, ~0.13 Wm-1K-1, with a slightly increasing trend. These converging results can be used to feed automation models for thermochemical reactors and to evaluate the influence of the hydration state of the salt. | en_US |
| dc.language.iso | EN | en_US |
| dc.publisher | Eurotherm Seminar | en_US |
| dc.rights.uri | inconnu | en_US |
| dc.subject.en | Composite, thermal conductivity, salt, thermo-gravimetry, climate chamber | en_US |
| dc.title | Monitoring of thermal properties of a composite material used in thermochemical heat storage | en_US |
| dc.title.en | Monitoring of thermal properties of a composite material used in thermochemical heat storage | en_US |
| dc.type | Acte de conférence ou de colloque | en_US |
| synhera.classification | Physique, chimie, mathématiques & sciences de la terre | en_US |
| synhera.institution | HE Libre de Bruxelles Ilya Prigogine | en_US |
| synhera.otherinstitution | ULB | en_US |
| dc.description.version | Oui | en_US |
| dc.rights.holder | inconnu | en_US |
