Materials characterization of innovative composite materials for solar-driven thermochemical heat storage (THS) suitable for building application

Abstract

Thermochemical Heat Storage (THS) systems have recently attracted a lot of attention in research and development. One of the main parameters that influence the performance of a THS system is the thermochemical materials. This paper aims to investigate thermochemical materials which are suitable for both short-term and long-term building heat storage application driven by solar energy for an open system. Innovative composite materials using MgCl2-MgSO4, CaCl2-LiCl and MgSO4- CaCl2 salts mixtures impregnated into vermiculite, and potassium formate (KCOOH) impregnated into silica gel will be presented in this study. Initial screening and characterization results of the composite THS materials based on the energy density using differential scanning calorimetry analysis, mass loss against temperature using thermo-gravimetric analysis, and moisture vapor adsorption isotherms testing are discussed. The characterization analysis suggest that the vermiculite with salts mixtures are promising candidates for thermochemical heat storage (THS) systems compared to composite materials with individual salts. Meanwhile the potential of KCOOH-silica gel as THS materials may be further investigated in the future. The performance of the materials may be further optimized in the future by changing the concentration ratio of the mixed salts.

Investigation on a Vermiculite-Based Solar Thermochemical Heat Storage System for Building Applications

“…Then the previouslystored thermochemical energy is released. Table 1 Vermiculite-based THS composite energy density and regeneration temperature analysed by SDT-Q600 (Jarimi et al 2017).…”

“…For instance, Casey et al (2015) found vermiculite-CaCl 2 was a promising candidate for open THS systems, which exhibited high heat storage capability and rapid mass uptake at higher relative humidity levels. The characterisation analysis conducted by Jarimi et al (2017) demonstrated the feasibility of using the vermiculite-based composite adsorbents in THS systems. The THS system is still under the research and development stage, which requires more studies on the innovative composite adsorbents and reactor designs (Shen et al, 2021).…”

“…Comparatively, thermochemical heat storage (THS) has been regarded as a promising alternative to the conventional TES, which stores energy by an endothermic chemical reaction and releases energy by a reversible reaction (Yan et al, 2015). THS demonstrates high energy storage density at ambient temperature, high exergetic efficiency, low heat loss, low regeneration temperature, low space-demanding and long-term storage stability (Jarimi et al, 2017, Sunku Prasad et al, 2019, Gil et al, 2010.…”

“…It has been reported that the energy density of THS materials is two times higher than latent energy storage materials and eight to ten times higher than sensible energy storage materials (Aydin et al, 2015). Referring to the studies (Han et al, 2022, Jarimi et al, 2017, Pardo et al, 2014, Dizaji and Hosseini, 2018, several factors are needed for taking into consideration to select a suitable THS material, including:…”

Scalable Production of EP/CaCl2@C Multistage Core–Shell Sorbent for Solar-Driven Sorption Heat Storage Application

“…One strategy is to prepare typical selective water sorbents “SWS”, − a two-component material based on a porous host matrix with an inorganic salt inside its pores. A series of porous materials are used as the matrix, such as zeolite, , silica gel, , activated alumina, metal–organic framework (MOF), , porous carbon material, porous minerals, , and others. , The salt crystals are dispersed in the pores, and the liquid products can be confined in the pores. However, there is still a problem that salt solution may overflow from the pores when the volume of the solution exceeds the pore volume of the matrixes.…”