TY - JOUR

T1 - Calcium hydroxide doped by KNO3 as a promising candidate for thermochemical storage of solar heat

AU - Shkatulov, Alexandr

AU - Aristov, Yuri

PY - 2017/1/1

Y1 - 2017/1/1

N2 - New materials for thermochemical storage of concentrated solar heat are highly desirable for making this emerging technology competitive with the traditional sensible and latent heat storage. Keeping this in mind, we have prepared calcium hydroxide modified with potassium nitrate and studied its de-/rehydration dynamics by differential scanning calorimetry and thermogravimetry techniques. The following notable observations are described for the modified Ca(OH)2: (1) an acceleration of the dehydration and reduction of its temperature as compared with the pure hydroxide; (2) the temperature reduction depends on the KNO3 content Y and reaches 35 °C at Y = 5 wt%; (3) the addition of KNO3 only slightly reduces the dehydration heat which remains promising for heat storage applications. Fast rehydration of the doped CaO is observed at T = 290-360 °C and P(H2O) = 23-128 mbar, and its rate strongly depends on both temperature and pressure. De- and rehydrated products were studied by the BET analysis and IR-spectroscopy to elucidate possible ways for the salt to influence the Ca(OH)2 dehydration. The mechanism involving a chemical interaction between the salt and the hydroxide is discussed. The new material exhibits a large heat storage density, fast de-/rehydration and adjustable decomposition temperature, and may be considered as a promising candidate for thermochemical storage of concentrated solar energy.

AB - New materials for thermochemical storage of concentrated solar heat are highly desirable for making this emerging technology competitive with the traditional sensible and latent heat storage. Keeping this in mind, we have prepared calcium hydroxide modified with potassium nitrate and studied its de-/rehydration dynamics by differential scanning calorimetry and thermogravimetry techniques. The following notable observations are described for the modified Ca(OH)2: (1) an acceleration of the dehydration and reduction of its temperature as compared with the pure hydroxide; (2) the temperature reduction depends on the KNO3 content Y and reaches 35 °C at Y = 5 wt%; (3) the addition of KNO3 only slightly reduces the dehydration heat which remains promising for heat storage applications. Fast rehydration of the doped CaO is observed at T = 290-360 °C and P(H2O) = 23-128 mbar, and its rate strongly depends on both temperature and pressure. De- and rehydrated products were studied by the BET analysis and IR-spectroscopy to elucidate possible ways for the salt to influence the Ca(OH)2 dehydration. The mechanism involving a chemical interaction between the salt and the hydroxide is discussed. The new material exhibits a large heat storage density, fast de-/rehydration and adjustable decomposition temperature, and may be considered as a promising candidate for thermochemical storage of concentrated solar energy.

KW - THERMAL-ENERGY STORAGE

KW - PUMP

KW - DECOMPOSITION

KW - MAGNESIUM

KW - ENHANCEMENT

KW - PERFORMANCE

KW - EFFICIENT

KW - KINETICS

KW - SYSTEMS

KW - NITRATE

UR - http://www.scopus.com/inward/record.url?scp=85029096625&partnerID=8YFLogxK

U2 - 10.1039/c7ra06639b

DO - 10.1039/c7ra06639b

M3 - Article

AN - SCOPUS:85029096625

VL - 7

SP - 42929

EP - 42939

JO - RSC Advances

JF - RSC Advances

SN - 2046-2069

IS - 68

ER -