Camila Barreneche

1 – Introduction to thermal energy storage (TES) systems

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.

New methodology developed for the differential scanning calorimetry analysis of polymeric matrixes incorporating phase change materials

Nowadays, thermal comfort needs in buildings have led to an increase in energy consumption of the residential and service sectors. For this reason, thermal energy storage is shown as an alternative to achieve reduction of this high consumption. Phase change materials (PCM) have been studied to store energy due to their high storage capacity. A polymeric material capable of macroencapsulating PCM was developed by the authors of this paper. However, difficulties were found while measuring the thermal properties of these materials by differential scanning calorimetry (DSC). The polymeric matrix interferes in the detection of PCM properties by DSC. To remove this interfering effect, a new methodology which replaces the conventional empty crucible used as a reference in the DSC analysis by crucibles composed of the polymeric matrix was developed. Thus, a clear signal from the PCM is obtained by subtracting the new full crucible signal from the sample signal.

19 – Thermal energy storage (TES) systems using heat from waste

Even though there are many references in the literature identifying the potential of thermal energy storage (TES) technologies for the recovery of waste heat in different industries, there are far fewer examples of the application of TES for waste heat management actually running in industry. This chapter focuses on a compilation of these cases. The first part of the chapter addresses the generation of waste process heat in different industries. The few real scenarios where the waste heat is valorized in combination with a thermal energy storage system are reported in the second part of the chapter.

Phase-change materials for reducing building cooling needs

This chapter shows how phase-change materials can be considered eco-efficient materials for mitigating building cooling demands. The chapter considers eco-efficiency from the point of view of materials and from the point of view of systems, that is, the use of eco-efficient materials and the use of materials that enable the system to be more eco-efficient. In this sense, phase-change materials are shown to contribute to the eco-efficiency of systems. The use of phase-change materials in passive and active systems is described in detail.

Study of the Thermal Properties and the Fire Performance of Flame Retardant-Organic PCM in Bulk Form

The implementation of organic phase change materials (PCMs) in several applications such as heating and cooling or building comfort is an important target in thermal energy storage (TES). However, one of the major drawbacks of organic PCMs implementation is flammability. The addition of flame retardants to PCMs or shape-stabilized PCMs is one of the approaches to address this problem and improve their final deployment in the building material sector. In this study, the most common organic PCM, Paraffin RT-21, and fatty acids mixtures of capric acid (CA), myristic acid (MA), and palmitic acid (PA) in bulk, were tested to improve their fire reaction. Several flame retardants, such as ammonium phosphate, melamine phosphate, hydromagnesite, magnesium hydroxide, and aluminum hydroxide, were tested. The properties of the improved PCM with flame retardants were characterized by thermogravimetric analyses (TGA), the dripping test, and differential scanning calorimetry (DSC). The results for the dripping test show that fire retardancy was considerably enhanced by the addition of hydromagnesite (50 wt %) and magnesium hydroxide (50 wt %) in fatty acids mixtures. This will help the final implementation of these enhanced PCMs in building sector. The influence of the addition of flame retardants on the melting enthalpy and temperatures of PCMs has been evaluated.

Materials Selection for Thermal Energy Storage Applications—Case Studies

To accomplish their duties, engineers need information, and this must be easily accessible, so they can readily choose among all the possibilities they can find to fit to a specific application. To build a thermal energy storage system, engineers always wonder which the best storage material they can find. The answer always depends on several factors. In the present chapter, the materials selection methodology is introduced to proceed for an optimal material selection for a certain application in thermal energy storage systems. Several case studies using this methodology are explained for different thermal energy storage applications: long term and short term sensible heat thermal energy storage, and phase change materials (PCM) for latent heat thermal energy storage for low temperature applications (buildings sector), and high temperature applications (concentrated solar power plants or CSP).

Experimental Methods for the Characterization of Materials for Latent Thermal Energy Storage

This chapter summarizes the techniques to characterize phase change materials for thermal energy storage applications. The most relevant properties include giving answer to physical, thermal, and technical requirements. The chapter includes characterisation at different scales, from laboratory (including latent heat, melting temperature, specific heat, thermal conductivity, durability and cyclability) to pilot plant scale, including a novel dynamic characterization of composites.

Recent Patents on Nano-Enhanced Materials for Use in Thermal Energy Storage (TES)

OBJECTIVE Thermal energy storage (TES) systems using phase change materials (PCM) have been lately studied and are presented as one of the key solutions for the implementation of renewable energies. These systems take advantage of the latent heat of phase change of PCM during their melting/ solidification processes to store or release heat depending on the needs and availability. Low thermal conductivity and latent heat are the main disadvantages of organic PCM, while corrosion, subcooling and thermal stability are the prime problems that inorganic PCM present. PREVENTION Nanotechnology can be used to overcome these drawbacks. Nano-enhanced PCM are obtained by the dispersion of nanoparticles in the base material and thermal properties such as thermal conductivity, viscosity and specific heat capacity, within others, can be enhanced. This paper presents a review of the patents regarding the obtaining of nano-enhanced materials for thermal energy storage (TES) in order to realize the development nanotechnologies have gained in the TES field. CONCLUSION Patents regarding the synthesis methods to obtain nano-enhanced phase materials (NEPCM) and TES systems using NEPCM have been found and are presented in the paper. The few existing number of patents found is a clear indicator of the recent and thus low development nanotechnology has in the TES field so far. Nevertheless, the results obtained with the reviewed inventions already show the big potential that nanotechnology has in TES and denote a more than probable expansion of its use in the next years.

Empirical equations for viscosity and specific heat capacity determination of paraffin PCM and fatty acid PCM

Phase change materials (PCM) used in thermal energy storage (TES) systems have been presented, over recent years, as one of the most effective options in energy storage. Paraffin and fatty acids are some of the most used PCM in TES systems, as they have high phase change enthalpy and in addition they do not present subcooling nor hysteresis and have proper cycling stability. The simulations and design of TES systems require the knowledge of the thermophysical properties of PCM. Thermal conductivity, viscosity, specific heat capacity (Cp) can be experimentally determined, but these are material and time consuming tasks. To avoid or to reduce them, and to have reliable data without the need of experimentation, thermal properties can be calculated by empirical equations. In this study, five different equations are given to calculate the viscosity and specific heat capacity of fatty acid PCM and paraffin PCM. Two of these equations concern, respectively, the empirical calculation of the viscosity and liquid Cp of the whole paraffin PCM family, while the other three equations presented are for the corresponding calculation of viscosity, solid Cp, liquid Cp of the whole fatty acid family of PCM. Therefore, this study summarize the work performed to obtain the main empirical equations to measure the above mentioned properties for whole fatty acid PCM family and whole paraffin PCM family. Moreover, empirical equations have been obtained to calculate these properties for other materials of these PCM groups and these empirical equations can be extrapolated for PCM with higher or lower phase change temperatures within a lower relative error 4%.

Industrial waste materials and by-products as thermal energy storage (TES) materials: A review

A wide variety of potential materials for thermal energy storage (TES) have been identify depending on the implemented TES method, Sensible, latent or thermochemical. In order to improve the efficiency of TES systems more alternatives are continuously being sought. In this regard, this paper presents the review of low cost heat storage materials focused mainly in two objectives: on the one hand, the implementation of improved heat storage devices based on new appropriate materials and, on the other hand, the valorisation of waste industrial materials will have strong environmental, economic and societal benefits such as reducing the landfilled waste amounts, reducing the greenhouse emissions and others. Different industrial and municipal waste materials and by products have been considered as potential TES materials and have been characterized as such. Asbestos containing wastes, fly ashes, by-products from the salt industry and from the metal industry, wastes from recycling steel process and from copper refining process and dross from the aluminium industry, and municipal wastes (glass and nylon) have been considered. This work shows a great revalorization of wastes and by-product opportunity as TES materials, although more studies are needed to achieve industrial deployment of the idea.A wide variety of potential materials for thermal energy storage (TES) have been identify depending on the implemented TES method, Sensible, latent or thermochemical. In order to improve the efficiency of TES systems more alternatives are continuously being sought. In this regard, this paper presents the review of low cost heat storage materials focused mainly in two objectives: on the one hand, the implementation of improved heat storage devices based on new appropriate materials and, on the other hand, the valorisation of waste industrial materials will have strong environmental, economic and societal benefits such as reducing the landfilled waste amounts, reducing the greenhouse emissions and others. Different industrial and municipal waste materials and by products have been considered as potential TES materials and have been characterized as such. Asbestos containing wastes, fly ashes, by-products from the salt industry and from the metal industry, wastes from recycling steel process and from copper ...