Thermal Diffusion in Fibrous Aerogel Blankets

Abstract

Nowadays, the usage of thermal insulation materials is widespread not only in the building sector but also in the vehicle industry. The application of fibrous or loose-fill insulation materials like glass wool or mineral wool as well as aerogel is well known. Aerogel-based materials are among the best solid materials for thermal insulation available today; they are prepared through a sol–gel process. For building walls, the glass-fiber-enhanced types are the frequently used ones. They are prepared by adding the liquid–solid solution to the fibrous batting, which is called a sol–gel process. In the present paper, the changes in the most important building physical properties of aerogel blankets after thermal annealing are presented. The samples were subjected to isochronal heat treatments from 70 to 210 °C for 24 h. The changes in the thermal conductivity were followed by Holometrix Lambda heat flow meter, and differential scanning calorimetry results were also recorded. From the measured values, together with the densities, the most important thermal properties were calculated, such as thermal resistance, diffusivity, effusivity (heat absorption), and thermal inertia. In this paper, we attempt to clarify the role played by thermal annealing in the transient thermal properties of aerogel materials. Besides presenting the measurement results, a theoretical background is given. The investigations of not only the steady-state but also the transient thermal parameters of the materials are momentous at the design stage.

Porous Aerogel Structures as Promising Materials for Photocatalysis, Thermal Insulation Textiles, and Technical Applications: A Review

“…The large surface area and porous nature of aerogels also make them excellent catalyst supports. They can enhance catalytic reactions by providing a high surface area for active sites, leading to improved efficiency in various industrial processes, such as chemical production and emissions control [183]. Aerogels have been explored as materials for energy storage applications, including supercapacitors and batteries.…”

Novolac aerogel thermal diffusion and efficiency enhancement using paraffin wax core/polyurethane shell phase‐change material nanocapsules

“…Due to this fact, a mathematical model based on temperature and NPCMs' physical properties has been suggested, which is proficient at predicting NPCMs' specific heat capacity in different temperature ranges as follows: where represents NPCMs' specific heat capacity () before melting temperature (), 28 means NPCMs' fusion latent heat (), 29 refers to surface area below NPCMs' differential scanning calorimetry (DSC) diagram at any time, is NPCMs' total surface area in DSC diagram and ultimately, represents the heating rate.…”

Experimental and Computational Study of Thermal Processes in Red Clays Exposed to High Temperatures

“…The values of effective specific heat capacity are then usually higher as their physical nature, but, in the field of computational modeling, they can be exploited very efficiently. An example of determination of such a parameter can be found, e.g., in the research presented by Lakatos and Trnik [30], who introduced the effective specific heat capacity of an aerogel blanket to incorporate thermal processes related to thermal annealing. The main objective of the model is therefore to find effective specific heat capacity vs. temperature functions of particular clays that, after processing by the computational model, produce the same heat flow diagrams as depicted in Figure 3.…”

“…The values of effective specific heat capacity are then usually higher as their physical nature, but, in the field of computational modeling, they can be exploited very efficiently. An example of determination of such a parameter can be found, e.g., in the research presented by Lakatos and Trnik [30], who introduced the effective specific heat capacity of an aerogel blanket to incorporate thermal processes related to thermal annealing.…”