https://pure.tue.nl/ws/files/51662523/1_s2.0_S0306261916319316_main.pdf

Sorption heat storage for long-term low-temperature applications: A review on the advancements at material and prototype scale

A viable way to manage the inherently intermittent availability of solar energy in concentrated solar power plants is to store solar energy during on-sun hours to be able to use it later during off-sun hours, enabling on-demand electricity delivery. Thermochemical heat storage systems present some noteworthy advantages when compared with latent and sensible heat storage, namely (i) high energy storage density because the storage capacity by unit of mass or volume corresponding to the reaction enthalpy is generally high, (ii) heat storage at room temperature and long term energy storage because the products can be cooled and stored at room temperature without energy losses as heat can be stored indefinitely in chemical bonds, (iii) facility of transport because solid materials can be transferred over long distances, (iv) constant restitution temperature providing constant heat source because exothermic reactions are carried out at sufficiently high temperatures to generate electricity in constant conditions and therefore to produce a constant power. This paper presents an overview of the different potential thermochemical systems based on reversible solid-gas reactions operating at high temperatures and a screening of suitable materials that are interesting candidates in the 400–1200 °C range for thermochemical heat storage in concentrated solar power systems. The most promising materials belonging to the metal oxides, hydroxides, and carbonates solid-gas systems are selected for experimental validation and further investigations.

Screening of thermochemical systems based on solid-gas reversible reactions for high temperature solar thermal energy storage

https://pure.tue.nl/ws/files/65069212/1_s2.0_S0306261917304750_main.pdf

A review of salt hydrates for seasonal heat storage in domestic applications

Aerogel fibers have been recognized as the rising star in the fields of thermal insulation and wearable textiles. Yet, the lack of functionalization in aerogel fibers limits their applications. Herein, we report hygroscopic holey graphene aerogel fibers (LiCl@HGAFs) with integrated functionalities of highly efficient moisture capture, heat allocation, and microwave absorption. LiCl@HGAFs realize the water sorption capacity over 4.15 g g-1, due to the high surface area and high water uptake kinetics. Moreover, the sorbent can be regenerated through both photo-thermal and electro-thermal approaches. Along with the water sorption and desorption, LiCl@HGAFs experience an efficient heat transfer process, with a heat storage capacity of 6.93 kJ g-1. The coefficient of performance in the heating and cooling mode can reach 1.72 and 0.70, respectively. Notably, with the entrapped water, LiCl@HGAFs exhibit broad microwave absorption with a bandwidth of 9.69 GHz, good impedance matching, and a high attenuation constant of 585. In light of these findings, the multifunctional LiCl@HGAFs open an avenue for applications in water harvest, heat allocation, and microwave absorption. This strategy also suggests the possibility to functionalize aerogel fibers towards even broader applications. 

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Hygroscopic holey graphene aerogel fibers enable highly efficient moisture capture, heat allocation and microwave absorption

Using phase change materials (PCMs) for thermal energy storage has always been a hot topic within the research community due to their excellent performance on energy conservation such as energy efficiency in buildings, solar domestic hot water systems, textile industry, biomedical and food agroindustry. Several literatures have reported phase change materials concerning various aspects. Among these materials, salt hydrates are worthy of exploring due to their high-energy storage density, rational price, multiple sources and relatively good thermal conductivity. This paper reviews the present state of salt hydrates PCMs targeting classification, properties, defects, possible solutions as well as their idiographic features which are suitable for applications. In addition, new trends of future research are also indicated.

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Inorganic Salt Hydrate for Thermal Energy Storage

Experimental Studies of the Mechanism and Kinetics of Hydration Reactions

Thermochemical investigation of the water uptake behavior of MgSO4 hydrates in host materials with different pore size

Thermal conductivity of selected salt hydrates for thermochemical solar heat storage applications measured by the light flash method

The mechanism and the kinetics of hydration reactions are important for the application of a salt hydrate as a thermochemical heat storage material. MgSO4∙H2O and Na2SO4 were chosen in this study because they are both promising candidates for such an a pplication. Considering that the hydration of these salts yields MgSO4∙7H2O and Na2SO4∙10H2O as the reaction products, the maximum overall heat effect can be calculated from the heat of condensation of water vapor (44 kJ mol –1 ) and the heats of hydration of 75 kJ∙mol -1 (for MgSO4∙H2O) and 81 kJ mol -1 (for Na2SO4). Based on the densities of the two hydrated phases, this results in the very high theoretical energy densities of 2.3 GJ·m -3 and 2.4 GJ·m -3 , respectively, for MgSO4∙7H2O and Na2SO4∙10H2O. Not only the energy density is important for the dimensioning of a storage system, but also the kinetics of h ydration reactions play a major role for the application as storage material. In the present study, hydration reactions under varying climatic conditions were investigated by using water vapor sorption measurements and in-situ Raman microscopy. Using t he phase diagrams, it can be clearly shown that the mechanism and the kinetics depend on the climatic conditions. Below the deliquescence humidity of the lower hydrated phase the hydration proceeds as solid state reaction, whilst above the deliquescence humidity a through solution mechanism takes place.

SHC 2013, International Conference on Solar Heating and Cooling for Buildings and Industry September 23-25, 2013, Freiburg, Germany Experimental studies of the mechanism and kinetics of hydration reactions

Konrad Posern

Papers

Experimental Studies of the Mechanism and Kinetics of Hydration Reactions

Thermochemical investigation of the water uptake behavior of MgSO4 hydrates in host materials with different pore size

Thermal conductivity of selected salt hydrates for thermochemical solar heat storage applications measured by the light flash method

SHC 2013, International Conference on Solar Heating and Cooling for Buildings and Industry September 23-25, 2013, Freiburg, Germany Experimental studies of the mechanism and kinetics of hydration reactions

Alginate‐Derived Salt/Polymer Composites for Thermochemical Heat Storage