Experimental Analysis of Salt Hydrate Latent Heat Thermal Energy Storage System With Porous Aluminum Fabric and Salt Hydrate as Phase Change Material With Enhanced Stability and Supercooling

Abstract

Phase change materials (PCM), especially salt hydrates possess high volumetric energy storage capacity in their transition temperature range. These materials are used in applications where it is necessary to store thermal energy due to temporary load shift between demand and availability. Thus, possible applications are HVAC, recovery of waste heat, and defense thermal management. In spite of salt hydrates potential, the practical feasibility of latent heat storage with salt hydrates is limited due to low power rating, supercooling, phase segregation, and long- term stability. Its low power rating and long-term stability limits its application in most applications. This work experimentally validates, the stability and thermal performance of a compact heat exchanger charged with salt hydrate during melting and freezing. The compact heat exchanger was designed with fins on both the Heat Transfer Fluid (HTF) and salt hydrate PCM side. The thermal performance of the Latent Heat Thermal Energy Storage System (LHTESS) were evaluated for various operating conditions. The results show that LHTESS could achieve an average heat transfer coefficient of 124 and 87 W/m2 - K during melting and solidification respectively. The stability of the system in suppressing supercooling were validated over 800 cycles with nucleating agent and active homogenous nucleation techniques. The supercooling was reduced to 3 °C with zinc hydroxyl nitrate as nucleating agent and less than 1 °C with active homogenous nucleation technique. The LHTESS showed less than 5% degradation in energy storage capacity over 800 cycles.

An investigation of the melting process in a latent heat thermal energy storage system using exhaust gases of a spark ignition engine

“…11,12 Except for conventional TES systems that use sensible heat, 13 TES systems, based on the latent heat of phase change materials (PCMs), attract more attention as they have a greater thermal energy storage capability. 14,15 Nowadays, latent heat thermal storage (LHTES) systems have made great development due to their high thermal energy storage potential. 16 In LHTES systems, usually using PCMs as storage media because of their ability to release or absorb thermal energy during a reversible liquid/solid phase change.…”

Machine Learning (ML) based Thermal Management for Cooling of Electronics Chips by Utilizing Thermal Energy Storage (TES) in Packaging that Leverage Phase Change Materials (PCM)

“…For a TES application requiring repeated thermocycling (i.e., repeated consecutive cycles of melting and freezing), CFT was demonstrated to be effective in reducing the degree of supercooling in LNT (from ~10 o C) to less than 1 o C (e.g., in the range of 0.5-1 o C). The authors demonstrated that using the CFT technique the LNT samples survived thermocycling tests that exceeded 800 cycles of repeated incomplete melting and complete solidification [25].…”

“…During intermittent operation of electronic devices -a heat sink filled with PCM can limit the peak value of the local temperature transients by rapid melting (faster discharging cycle) and release the heat when the device is idle (slow period of freezing, i.e., slower charging cycle). During thermocycling of PCM, the power rating is typically higher during the charging cycle (i.e., during melting, since it is dominated by free-convection heat transfer) and the power rating is lower during the discharging cycle (i.e., during freezing, since it is dominated by conduction heat transfer and convection is almost negligible) [25]. Thus, this strategy helps with extending the time required to reach the peak temperature of the heat sink, especially under critical load conditions [29].…”

Machine Learning (ML) Based Thermal Management for Cooling of Electronics Chips by Utilizing Thermal Energy Storage (TES) in Packaging That Leverages Phase Change Materials (PCM)

“…For a TES application requiring repeated thermocycling (i.e., repeated consecutive cycles of melting and freezing), CFT was demonstrated to be effective in reducing the degree of supercooling in LNT (from ~10 • C) to less than 1 • C (e.g., in the range of 0.5-1 • C). The authors demonstrated that using the CFT technique the LNT samples survived thermocycling tests that exceeded 800 cycles of repeated incomplete melting and complete solidification [25].…”