/pdf/design-and-assessments-on-a-hybrid-pin-fin-metal-foam-1mdn2t5r.pdf

Design and assessments on a hybrid pin fin-metal foam structure towards enhancing melting heat transfer: An experimental study

Taking the casing phase change heat storage unit filled with RT55 as the research object. According to the low thermal conductivity of phase change materials, we propose a Phase Change Material (PCM) sleeve with snowflake longitudinal fin structure to improve the melting performance of vertical latent heat storage system (LHTES), and the phase change heat transfer process is simulated by numerical simulation. We studied the enhanced heat transfer characteristics of the snowflake-shaped fin structure to the casing PCM unit, and compared with the ordinary rectangular longitudinal fin and the improved snowflake-shaped longitudinal fin. The results show that the combined mechanism of snowflake finned tube structure and local heat transfer of phase change materials can significantly shorten the charging time, which is 45.59% lower than that of traditional fin melting time. Reasonable changes in fin length, width, shape and angle structure can shorten the charging time, but reduce the heat storage. We analyzed the thermal performance of the heat storage system by taking the charging time, heat storage capacity and average heat flux as evaluation indexes, and discussed the effects of flow temperature in the tube, fin material and longitudinal fin shape on the melting performance of the system. 

Study on thermal performance of a new optimized snowflake longitudinal fin in vertical latent heat storage

Investigation on the thermal performance of a multi-tube finned latent heat thermal storage pool

Considering the increasing gap between energy demand and clean energy supply availability, there is a strong need to impart novel design structures to effectively utilize the available resources and energy storage systems. Nature-inspired fin structures embedded with well-chosen phase change materials (PCM) can play an essential role in improving the heat transfer in thermal energy storage devices. The present work investigates the melting and solidification processes in a metallic heat exchanger filled with n-octadecane as working PCM, with tree-shaped fins. The study is conducted for various fin generation numbers, volume fractions, length ratios, and angles between the Y-shaped tree fin branches. The results are discussed in the form of melt fraction of PCM, heated surface average temperature variation, and thermal energy stored. The results clearly indicate that the heat transfer is significantly improved with increasing branches of the tree-structured fins because of an increased area available for heat transfer. This study can be utilized to enhance the performance of PCM embedded thermal energy storage devices. 

Melting and solidification of a phase change material with constructal tree-shaped fins for thermal energy storage

Experimental and numerical studies on the heat transfer improvement of a latent heat storage unit using gradient tree-shaped fins

Thermal energy is stored in a packed bed thermal energy storage (PBTES) system by raising the temperature of the packing elements. This simple mechanism and economic feasibility (Gautam and Saini, 2020) make the PBTES promising for applications such as solar thermal power plants, building cooling systems, and waste heat recovery (Nallusamy et al., 2007). The traditional PBTES is based on sensible heat transfer and is therefore limited by a low energy density and temperature stability (Mawire et al., 2020). Compared with the traditional system, a packed bed latent heat storage (PBLHS) system based on phase-change materials (PCMs) (Wang H. et al., 2018; Wang J. et al., 2018) offers advantages such as a higher energy density, higher temperature stability, and few safety issues (Li et al., 2018; Kumar and Saha, 2021; Wang et al., 2021) and therefore is considered a promising solution for thermal energy storage (Yang et al., 2017; Zhang et al., 2020; Grabo et al., 2021). This study reviews recent progress on low-temperature PBLHS systems with phase-change points below 100°C. A brief discussion of the working principle and impact factors of the PBLHS system is presented based on results from recent studies (Alptekin and Ezan, 2021). The performance and applications of PBLHS systems are also discussed.

/pdf/perspectives-on-low-temperature-packed-bed-latent-heat-5hzqym35.pdf

Dongcheng Cao

Papers

Experimental and numerical studies on the heat transfer improvement of a latent heat storage unit using gradient tree-shaped fins

Perspectives on Low-Temperature Packed Bed Latent Heat Storage Systems