Abstract
The thermal conductivity of composites "inorganic salt in porous matrix" was measured as function of the water uptake w by a "hot wire" method. Three hygroscopic salts (CaCl2, MgCl2, LiBr) were confined to the pores of a commercial KSK silica gel. For CaCl 2, an alumina was used as host matrix, too. Similar dependencies λ(w) were found for the three silica based sorbents: a smooth rise at w < w* = 0.4-0.55 and a sharp increase within the narrow w-range near the threshold uptake w*. Regardless the salt confined, this increase occurs at the same fraction ν of the pore volume occupied by the salt solution, ν* = 0.60-0.64. At ν > ν* the solution starts to leak out of the pores to form a liquid film on the external surface of silica particles that strongly facilitates the heat transfer between adjacent particles and enhances the heat conductivity of the whole bed. No such threshold behaviour was found for CaCl2/alumina composites. The data obtained can be used for analysing open and closed adsorptive units for heat transformation, gas drying, extraction of potable water from the atmosphere, etc. For user friendliness, the experimental λ(w)-dependences were approximated by polynomial equations.
| Original language | English |
|---|---|
| Pages (from-to) | 401-407 |
| Number of pages | 7 |
| Journal | Applied Thermal Engineering |
| Volume | 61 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 17 Sep 2013 |
Fingerprint
Keywords
- Adsorptive heat transformation and storage
- Composite sorbent
- Thermal conductivity
- Threshold effect of sorbed water
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Industrial and Manufacturing Engineering
Cite this
Thermal conductivity of composite sorbents "salt in porous matrix" for heat storage and transformation. / Tanashev, Yuri Yu; Krainov, Alexandr V.; Aristov, Yuri I.
In: Applied Thermal Engineering, Vol. 61, No. 2, 17.09.2013, p. 401-407.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Thermal conductivity of composite sorbents "salt in porous matrix" for heat storage and transformation
AU - Tanashev, Yuri Yu
AU - Krainov, Alexandr V.
AU - Aristov, Yuri I.
PY - 2013/9/17
Y1 - 2013/9/17
N2 - The thermal conductivity of composites "inorganic salt in porous matrix" was measured as function of the water uptake w by a "hot wire" method. Three hygroscopic salts (CaCl2, MgCl2, LiBr) were confined to the pores of a commercial KSK silica gel. For CaCl 2, an alumina was used as host matrix, too. Similar dependencies λ(w) were found for the three silica based sorbents: a smooth rise at w < w* = 0.4-0.55 and a sharp increase within the narrow w-range near the threshold uptake w*. Regardless the salt confined, this increase occurs at the same fraction ν of the pore volume occupied by the salt solution, ν* = 0.60-0.64. At ν > ν* the solution starts to leak out of the pores to form a liquid film on the external surface of silica particles that strongly facilitates the heat transfer between adjacent particles and enhances the heat conductivity of the whole bed. No such threshold behaviour was found for CaCl2/alumina composites. The data obtained can be used for analysing open and closed adsorptive units for heat transformation, gas drying, extraction of potable water from the atmosphere, etc. For user friendliness, the experimental λ(w)-dependences were approximated by polynomial equations.
AB - The thermal conductivity of composites "inorganic salt in porous matrix" was measured as function of the water uptake w by a "hot wire" method. Three hygroscopic salts (CaCl2, MgCl2, LiBr) were confined to the pores of a commercial KSK silica gel. For CaCl 2, an alumina was used as host matrix, too. Similar dependencies λ(w) were found for the three silica based sorbents: a smooth rise at w < w* = 0.4-0.55 and a sharp increase within the narrow w-range near the threshold uptake w*. Regardless the salt confined, this increase occurs at the same fraction ν of the pore volume occupied by the salt solution, ν* = 0.60-0.64. At ν > ν* the solution starts to leak out of the pores to form a liquid film on the external surface of silica particles that strongly facilitates the heat transfer between adjacent particles and enhances the heat conductivity of the whole bed. No such threshold behaviour was found for CaCl2/alumina composites. The data obtained can be used for analysing open and closed adsorptive units for heat transformation, gas drying, extraction of potable water from the atmosphere, etc. For user friendliness, the experimental λ(w)-dependences were approximated by polynomial equations.
KW - Adsorptive heat transformation and storage
KW - Composite sorbent
KW - Thermal conductivity
KW - Threshold effect of sorbed water
UR - http://www.scopus.com/inward/record.url?scp=84883771245&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84883771245&partnerID=8YFLogxK
U2 - 10.1016/j.applthermaleng.2013.08.022
DO - 10.1016/j.applthermaleng.2013.08.022
M3 - Article
AN - SCOPUS:84883771245
VL - 61
SP - 401
EP - 407
JO - Applied Thermal Engineering
JF - Applied Thermal Engineering
SN - 1359-4311
IS - 2
ER -