Analysis on the Improvement of Thermal Performance of Phase Change Material Ba (OH)2·8H2O

Xiaohui Lu,Xiaoxue Luo,Changzhen Zou,Shibo Cao

doi:10.3390/en14227761

Abstract

Benefitting from the characteristics of a high latent heat capacity and stable phase change behavior, phase change materials have widely received concerns in the field of thermodynamic management. Ba(OH)2·8H2O is an ideal phase change material (PCM) in the mid-to-low temperature range, but its large-scale application is still limited by severe supercooling during the nucleation process. In this paper, the experimental analysis and comparison are performed via an Edisonian approach, where Ba(OH)2·8H2O is adopted as an original substrate; BaCO3, CaCl2, NaCl, KH2PO4, and NaOH are selected as nucleating agents; and graphite is used as a heat-conducting agent. The results show that Ba(OH)2·8H2O containing 1.2% BaCO3 and 0.2% graphite powder has the best performance. Compared with pure Ba(OH)2·8H2O, the supercooling degree is reduced to less than 1 °C, the phase change latent heat duration is extended, and the thermal conductivity is significantly improved. Therefore, this study not only provides a reference for the application of Ba(OH)2·8H2O, but can also be used as a guidance for other material modifications.

Highlights

Nonrenewable fossil energy still plays an important role in most industrial fields around the world
The results showed that when the mass ratio of two hydrated salts obtained 1:9, the lowest degree of supercooling was 8.1 ◦ C
The heat storage performance of the phase storage materials mainly determined by factors such as the supercooling degreechange and theheat latent heat value

Summary

Introduction

Nonrenewable fossil energy still plays an important role in most industrial fields around the world. Fossil energy inevitably produces a large amount of greenhouse gas CO2 and other pollutants, threatening human health and the global ecological environment [1,2,3]. In this consideration, mankind tends to explore renewable energy sources and improve the energy demand in the development of future societies. The supercooling phenomenon of the inorganic hydrated salt leads to low latent heat recovery rates and insufficient material stability. This is a periodic change, and the major problem should be solved for the development of energy storage technology [9,10,11]. The degree of the delay in the crystallization process is called the supercooling degree [14]

Methods

Results

Conclusion