Advances in Thermal Energy Storage Systems

Methods and Applications

Luisa F. Cabeza

• Publisher: Woodhead Publishing
• Year: 2014
• ISBN:
  9781782420965
• Topic: Technology & Engineering
• Subtopic: Power Resources
• Index: Technology & Engineering

Thermal energy storage (TES) technologies store thermal energy (both heat and cold) for later use as required, rather than at the time of production. They are therefore important counterparts to various intermittent renewable energy generation methods and also provide a way of valorising waste process heat and reducing the energy demand of buildings. This book provides an authoritative overview of this key area. Part one reviews sensible heat storage technologies. Part two covers latent and thermochemical heat storage respectively. The final section addresses applications in heating and energy systems.

• Reviews sensible heat storage technologies, including the use of water, molten salts, concrete and boreholes
• Describes latent heat storage systems and thermochemical heat storage
• Includes information on the monitoring and control of thermal energy storage systems, and considers their applications in residential buildings, power plants and industry

1

Introduction to thermal energy storage (TES) systems

L.F. Cabeza¹; I. Martorell¹; L. Miró¹; A.I. Fernández²; C. Barreneche^{2 1} Universitat de Lleida, Spain
² Universitat de Barcelona, Spain

Abstract

Thermal energy storage (TES) systems can store heat or cold to be used later, under varying conditions such as temperature, place or power. TES systems are divided in three types: sensible heat, latent heat, and thermochemical. Clues for each TES system are presented in this chapter and requirements for each technology and application are given. An overview of system types and description of particular and novel applications are presented. The potential for energy saving and climate change mitigation using TES with a 10-year scenario is presented for specific cases. Finally, the CO₂ mitigation potential of TES in different applications is presented.

Keywords

Thermal energy storage (TES)

sensible heat

latent heat

phase change material (PCM)

thermochemical energy storage

Requirements

Applications

Overview

Energy savings

CO₂ mitigation potential

1.1 Introduction

Thermal energy storage (TES) systems can store heat or cold to be used later under varying conditions such as temperature, place or power. The main use of TES is to overcome the mismatch between energy generation and energy use [1–3]. In TES systems energy is supplied to a storage system to be used at a later time, involving three steps: charge, storage and discharge, giving a complete storage cycle (Figure 1.1).

Figure 1.1 TES complete storage cycle [3].

Storage concepts are active or passive systems (Figure 1.2) [4]. An active storage system is characterized by forced convection heat transfer into the storage material. The storage material circulates through a heat exchanger, a solar receiver or a steam generator. Active storage systems can be direct, the heat transfer fluid (HTF) serving also as storage medium, or indirect systems, where a second medium is used for storing the heat. Passive storage systems are generally dual-medium storage systems, where the HTF passes through the storage only for charging and discharging a solid material.

Figure 1.2 Scheme of classification of different storage systems according to the storage concept [3].

The main requirements for the design of a TES system are high energy density in the storage material (storage capacity), good heat transfer between the HTF and the storage material, mechanical and chemical stability of the storage material, compatibility between the storage material and the container material, complete reversibility of a number of cycles, low thermal losses during the storage period, and easy control. Moreover, the most important design criteria are the operation strategy, the maximum load needed, the nominal temperature and enthalpy drop, and the integration into the whole application system.

The benefits that can be obtained when implementing storage in an energy system are:

• better economics: reducing capital and operational costs

• better efficiency: achieving a more efficient use of energy

• less pollution of the environment and less CO₂ emissions

• better system performance and reliability.

Arce et al. [5] calculated the potential of saved energy due to the use of thermal energy storage in Europe. The buildings and industrial sectors were evaluated, and grouped in cases where TES may be applied.

The cases considered for the buildings sector were seasonal solar thermal systems, district/central heating, short-term solar thermal systems, and passive cold systems. For the industrial sector the cases considered were combined heat and power (CHP, also called cogeneration), industry (heating and cooling systems), power stations and transport, and concentrated solar power plants.

In order to determine the TES potential, the required parameters are related to energy and CO₂ emissions. Within the energy field, two quantities show the potential to be determined: the derived thermal load reduction and thermal/electrical energy savings.

The thermal load reduction refers to the reduction of ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• List of contributors
• Woodhead Publishing Series in Energy
• Preface
• 1: Introduction to thermal energy storage (TES) systems
• Part One: Sensible heat storage systems
• Part Two: Latent heat storage systems
• Part Three: Thermochemical heat storage systems
• Part Four: Systems operation and applications
• Index