Thermal energy storage (TES) systems using phase change material (PCM) have been recognized as one of the most advanced energy technologies in enhancing the energy efficiency and sustainability of buildings. Now the research is focus on suitable method to incorporate PCMs with building. There are several methods to use phase change materials (PCMs) in thermal energy storage (TES) for different applications. Microencapsulation is one of the well known and advanced technologies for better utilization of PCMs with building parts, such as, wall, roof and floor besides, within the building materials. Phase change materials based microencapsulation for latent heat thermal storage (LHTS) systems for building application offers a challenging option to be employed as effective thermal energy storage and a retrieval device. Since the particular interest in using microencapsulation PCMs for concrete and wall/wallboards, the specific research efforts on both subjects are reviewed separately. This paper presents an overview of the previous research work on microencapsulation technology for thermal energy storage incorporating the phase change materials (PCMs) in the building applications, along with few useful conclusive remarks concluded from the available literature.

Development of phase change materials based microencapsulated technology for buildings: a review

Microencapsulation of phase change materials (PCMs) is an effective way of enhancing their thermal conductivity and preventing possible interaction with the surrounding and leakage during the melting process, where there is no complete overview of the several methods and techniques for microencapsulation of different kinds of PCMs that leads to microcapsules with different morphology, structure, and thermal properties. In this paper, microencapsulation methods are perused and classified into three categories, i.e. physical, physic-chemical, and chemical methods. It summarizes the techniques used for microencapsulation of PCMs and hence provides a useful tool for the researchers working in this area. Among all the microencapsulation methods, the most common methods described in the literature for the production of microencapsulated phase change materials (MEPCMs) are interfacial polymerization, suspension polymerization, coacervation, emulsion polymerization, and spray drying.

A review of microencapsulation methods of phase change materials (PCMs) as a thermal energy storage (TES) medium

Organic phase change materials and their textile applications: An overview

Application of phase change materials for thermal energy storage in concentrated solar thermal power plants: A review to recent developments

This paper presents a detailed review of effect of phase change material (PCM) encapsulation on the performance of a thermal energy storage system (TESS). The key encapsulation parameters, namely, encapsulation size, shell thickness, shell material and encapsulation geometry have been investigated thoroughly. It was observed that the core-to-coating ratio plays an important role in deciding the thermal and structural stability of the encapsulated PCM. An increased core-to-coating ratio results in a weak encapsulation, whereas, the amount of PCM and hence the heat storage capacity decreases with a decreased core-to-coating ratio. Thermal conductivity of shell material found to have a significant influence on the heat exchange between the PCM and heat transfer fluid (HTF). This paper also reviews the solidification and melting characteristics of the PCM and the effect of various encapsulation parameters on the phase change behavior. It was observed that a higher thermal conductivity of shell material, a lower shell size and high temperature of HTF results in rapid melting of the encapsulated PCM. Conduction and natural convection found to be dominant during solidification and melt processes, respectively. A significant enhancement in heat transfer was observed with microencapsulated phase change slurry (MPCS) due to direct surface contact between the encapsulated PCM and the HTF. It was reported that the pressure drop and viscosity increases substantially with increase in volumetric concentration of the microcapsules.

A review on effect of phase change material encapsulation on the thermal performance of a system

Preparation and characterization of novel nanoencapsulated phase change materials

Nanoencapsulated phase change material with polystyrene as the shell and n-octadecane as the core was synthesized using the ultrasonic technique and miniemulsion in situ polymerization. The influences of polymerization factors, including initiator, chain transfer agent (CTA), surfactant, n-octadecane/styrene ratio and hydrophilic co-monomer, on the morphology and thermophysical properties of nanocapsules were systematically investigated. The optimized polymerization conditions were 0.5 wt% of initiator (2,2-azobisisobutyronitrile), 0.4 wt% of CTA (n-dodecyl mercaptan), 2% of composite surfactants which were composed of sodium dodecyl sulfate and poly-(ethylene glycol) monooctylphenyl ether by 1 : 1 in weight ratio, 1 wt% of hydrophilic co-monomer butyl acrylate or 3 wt% of methyl methacrylate and 1 : 1 n-octadecane to styrene in weight ratio. Under these conditions, the z-average size of prepared nanocapsules was 124 nm and the phase change enthalpy was 124.4 kJ kg −1 . The heat capacity was as high as 11.61 kJ kg −1 K −1 at the latex concentration of 20.6 wt%. Thermal stability and viscosity testing show that this fluid had excellent resistance to thermal shock (after 100 cycles, no liquid Oct was observed during heating) and low viscosity (only 3.61 mPa s at the latex concentration of 20.6 wt%), which seems to be promising as a latent functionally thermal fluid.

https://iopscience.iop.org/article/10.1088/0022-3727/42/3/035407/pdf

Shengyan Kuang

Papers

Preparation and characterization of novel nanoencapsulated phase change materials

Preparation of nanoencapsulated phase change material as latent functionally thermal fluid