Recent Investigations of Phase Change Materials Use in Solar Thermal Energy Storage System

Qianjun Mao,Ning Liu,Li Peng

doi:10.1155/2018/9410560

Abstract

Solar thermal energy storage (TES) is an efficient way to solve the conflict between unsteady input energy and steady output energy in concentrating solar power plant. The latent heat thermal energy storage (LHTES) system is a main method of storing thermal energy using phase change materials (PCMs). Thermal properties, that is, melting points and latent heat, are the key parameters of PCMs for the TES system. In this paper, the PCMs are classified into inorganic and organic by the chemical composition, and according to the melting point, the inorganic PCMs can be divided into three contributions: low-temperature heat storage (less than 120°C), medium-temperature heat storage (120–300°C), and high-temperature heat storage (more than 300°C). The present article focuses mainly on the recent investigations on the melting point and latent heat of PCMs via DSC setup in the solar TES systems. The results can provide a good reference for the selection and utilization of PCMs in the solar TES systems.

Highlights

With the essential increasing in energy consumption, energy shortage and environmental problem including tremendous demand and insufficient supply have been vital points that affect the economic development all over the world. e governments of many countries stimulate development of energy-saving technologies based on utilization of renewable energy sources [1]
The unpredictability of the output of renewable energy systems demands reliable and efficient energy storage units. erefore, thermal energy storage (TES) technology plays a significant role in utilizing the renewable resources [5, 6]. ere are mainly two types of TES systems of sensible storage systems and latent storage systems, and the latent heat thermal energy storage (LHTES) system is an effective way of storing thermal energy [7]
The thermal performances of phase change materials (PCMs) are similar to conventional storage materials which absorb heat with the increase of temperature in PCMs, and PCMs absorb and release heat at a nearly constant temperature compared with the conventional storage materials [8, 9]. erefore, the PCM is currently seen as one of the most promising to research the TES system

Summary

Introduction

With the essential increasing in energy consumption, energy shortage and environmental problem including tremendous demand and insufficient supply have been vital points that affect the economic development all over the world. e governments of many countries stimulate development of energy-saving technologies based on utilization of renewable energy sources [1]. Some review articles have a summary in the open literatures, which focus on as follows: TES system design methodologies and the factors [10]; the materials and heat transfer performance enhancement techniques of LHTES [11, 12]; the materials, heat transfer, and phase change problem for LHTES [13]; residential scale systems for seasonal storage of solar thermal energy [14]; TES technologies using PCM capsules [5]; CFD (Fluent) software applications in LHTES [15]; PCMs for high-temperature TES system [1]; microencapsulation PCMs for TES [16]; thermal stability of PCM [17]; the preparation, thermal properties, and applications of shape-stabilized thermal energy storage materials [18]; mathematical modeling on LHTES [19]; passive LHTES system to building’s energy. Based on melting point, the PCMs can be divided into three contributions: low-temperature heat storage (less than 120°C), medium-temperature heat storage (120–300°C), and hightemperature heat storage (more than 300°C). is can provide a theoretical guidance in future for selecting the more suitable PCMs in the investigations of the thermal performance for TES applications

Thermal Properties of PCMs with DSC

Inorganic Materials

Findings

Conclusions