Energy efficiency has emerged as a crucial component of sustainability efforts worldwide. Despite significant technological advancements, vast quantities of low-temperature waste heat produced by industrial processes remain untapped. In a groundbreaking study from Japan, researchers are delving into the potential of erythritol slurry as an innovative heat transfer medium for thermal storage and transport. By examining the flow dynamics and non-Newtonian properties of erythritol, the research team has formulated a predictive equation for its rheological characteristics. This exploration could be pivotal in designing effective industrial waste heat recovery systems, contributing significantly to energy efficiency and the pursuit of carbon neutrality.
At the heart of maintaining energy efficiency is a fundamental need to optimize every unit of energy produced and consumed. One of the most neglected resources is waste heat generated in factories, particularly in the low-temperature range, which is often below 230 °C. Many experts across the globe are investigating methods to repurpose this waste heat as thermal energy, either by reusing it in industrial operations or converting it into other valuable forms, such as residential heating systems. The first crucial step in this endeavor involves creating an effective latent heat storage and transport system.
The interest in utilizing phase change materials (PCM) slurries for thermal energy management has been steadily growing over the past few decades. These materials are notable for their ability to release a significant amount of heat during phase transitions, making them ideal candidates for waste heat management. Among various materials, erythritol—an organic compound that functions as a sugar alcohol—has caught the attention of a research team led by Project Assistant Professor Shunsuke Abe at Shinshu University.
In their latest research, which was published on February 06, 2025, in the esteemed journal "Experimental Thermal and Fluid Science," the researchers set out to explore erythritol slurry as a viable heat transfer medium. Co-authored by graduate student Hikaru Ebihara and Associate Professor Tatsunori Asaoka from the same institution, the study is expected to provide vital insights that pave the way for more efficient thermal storage and transport practices.
The researchers conducted a series of experiments to analyze how density differences between dispersed erythritol particles and the carrier fluid—a solution of erythritol and water—influence the rheological behavior and flow patterns of the slurry. By employing laminar flow conditions within horizontal circular tubes, they systematically measured both pressure drops and flow rates while varying solid fractions and the density differences of components.
Erythritol slurry’s intriguing non-Newtonian behavior is a focal point in the study, as it indicates that the mixture’s viscosity fluctuates based on flow conditions. At higher solid fractions, for instance, the team noted a pronounced tendency for the slurry to exhibit decreased viscosity at increased flow rates. Conversely, at lower solid fractions, variations in carrier concentration had a minimal effect on viscosity, indicating complex interplays that could benefit from deeper investigation.
To quantify these behaviors, the researchers utilized the particle Reynolds number, a pivotal metric that elucidates the interaction of solid particles with the surrounding fluid. This parameter depends on slurry velocity, density discrepancies, the viscosity of the carrier fluid, and particle size. Their findings revealed a significant relationship between the particle Reynolds number, solid fraction, and the degree of non-Newtonian effects exhibited by the slurry.
The ability to establish a reliable correlation between these factors and the power-law index—a critical measure of non-Newtonian behavior—sets the stage for new methodologies in predicting the transport properties of PCM slurries. As noted by Dr. Abe, these insights could inform the design of energy-efficient thermal transport systems essential for advancing the field further.
The implications of this research are far-reaching and could lead to various applications geared towards sustainability. For instance, erythritol slurry’s capabilities can be harnessed to recover waste heat in factories and power plants, where it can efficiently transport low- to medium-temperature waste heat, thereby addressing a significant energy loss point in these sectors.
Residential and commercial heating systems also stand to benefit from this research. Dr. Abe emphasizes that thermal storage systems utilizing PCM slurries can store heat during off-peak hours and subsequently release it when demand surges. This practice not only balances energy loads effectively but also enhances efficiency, ultimately reducing peak power demands—a key component in maintaining grid stability.
Furthermore, the integration of PCM slurries into cogeneration systems, or combined heat and power (CHP) plants, demonstrates additional avenues for energy optimization. These systems can simultaneously generate electricity and useful heat from a singular energy source, vastly improving energy efficiency compared to traditional methods. When paired with PCM slurries, cogeneration systems can capitalize on excess heat storage and ensure that it is available precisely when needed.
This study marks a significant step towards a sustainable, carbon-neutral future by revealing new methods to utilize available energy in its multifunctional forms. The advancements in understanding erythritol slurry’s rheological properties and behaviors exemplify how innovative research can drive the quest for sustainability, addressing critical challenges in energy recovery and utilization.
As the global community continues to seek solutions to energy efficiency and waste heat recovery, these findings from Shinshu University underscore the importance of interdisciplinary approaches to resolving complex environmental and technological challenges. With ongoing research and continued collaboration, the journey towards optimizing waste heat utilization through erythritol slurry and other PCM alternatives promises to reshape industrial practices and contribute to a sustainable future.
In summary, the innovative work being undertaken at Shinshu University not only impriments our technical understanding of erythritol slurry but also serves as a valuable cornerstone in the global objective of energy efficiency and sustainability.
Subject of Research: Investigating erythritol slurry as a heat transfer medium for thermal storage and transport.
Article Title: Effect of carrier concentration on rheological behavior of high density PCM slurry.
News Publication Date: February 06, 2025.
Web References: Published Online in Experimental Thermal and Fluid Science.
References: DOI: 10.1016/j.expthermflusci.2025.111429.
Image Credits: Credit: Shunsuke Abe of Shinshu University.
Keywords
Energy efficiency, waste heat management, erythritol slurry, thermal storage, non-Newtonian properties, phase change materials, sustainable technology, rheological characteristics.
