Low‐temperature and pressureless in‐situ self‐assembled SiC _w / SiC composite ceramics for solar thermal absorber and storage integration

Abstract

Summary Compared with current research of simply improving the efficiency of thermal absorber or thermal storage, integrating two devices into one fundamentally avoids the heat transfer loss between the two devices. In‐situ self‐assembled SiCw(SiC whisker)/SiC composite ceramics for integrated thermal absorber and thermal storage were pressurelessly prepared from graded SiC, AlN, and Si powders by layered powder embedded sintering in a low temperature range from 1450°C to 1650°C. After sintered at 1550°C, sample A4 with 10.39 wt% Si not only exhibits optimal mechanical properties and excellent thermal shock resistance, but also has high thermal conductivity, thermal storage capacity, and solar absorptance as 6.74 W·(m K)−1, 984.75 kJ·kg−1, and 91.12%, respectively. Results indicate that the in‐situ self‐assembled SiC whiskers, formed by carburization reaction via VS mechanism in the stacking voids of SiC matrix, could greatly enhance the mechanical and thermal properties. We creatively proposed that the as‐prepared SiCw/SiC is promising to apply in integrated thermal absorber and storage system of solar thermal power generation.

Study on magnesia alumina spinel heat storage ceramics for solar thermal power generation

“…Closed pores merge and open pores increase, so the apparent porosity increases and the bending strength decreases. The sample B4 at 1510 • C has the best comprehensive physical properties, with Wa of .12%, AP of .39%, D of 3.27 g/cm 3 , and σ b of 89.41 MPa. With the addition of TiO 2 , magnesium aluminate spinel can be synthesized at a lower temperature and obtain a higher density.…”

“…According to Equation ( 5), the value of heat storage density from room temperature to 1000 • C can be calculated. 3 The heat storage density is 0-1218.75 kJ/kg (from room temperature to 1000 • C).…”

“…The low-temperature working medium flows through the device to heat the working medium into high temperature working medium, so as to promote the power generation device to generate electricity. [2][3][4] However, the solar irradiation is affected by the alternation of day and night, the change of weather and the region, and the heat absorption of the heat collecting device has the characteristics of discontinuity. At present, heat storage devices are mainly added in solar thermal power generation systems.…”

Preparation of MgAl2O4 solar thermal storage ceramics from different magnesium sources

“…Therefore, thermal storage ceramics have become the research hotspot on thermal storage materials in the field of solar thermal power generation. Nowadays, there are plenty of researchers have prepared thermal storage ceramics with different crystalline phases, such as mullite, 3 cordierite, 4 anorthite, 5 silicon carbide 6 . With reference to these ideas, this work intends to prepare MgAl 2 O 4 thermal storage ceramics with different magnesium sources, on which there are few researches before.…”

In-situ growth of SiC w on the surface of C/C composite materials and different influencing factors on the morphology control of SiC w transition layer

“…However, in analyzing the in-situ growth of SiC w on C/C composite material surfaces, many researchers have merely employed traditional V-L-S (vapor-liquid-solid) mechanisms to expound upon the process, disregarding the presence of numerous dislocations and defects on the C/C surface, which can serve as active growth sites [13][14][15][16]. This factor lowers the energy required for SiC w growth, allowing whiskers to also grow via the V-S (vapor-solid) mechanism [17,18]. This paper primarily investigates the mechanism of in-situ growth of SiC w on the surface of C/C composite materials.…”