BITS Faculty Publications
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Item Thermal Energy Storage Properties of Hybrid Nanocomposite–Embedded Phase Change Material for Sustainable Buildings(Scientific net, 2014) Parameshwaran, R.The thermal properties of the new copper–titania hybrid nanocomposite embedded organic ester phase change material (HNPCM) were analyzed experimentally. The surface functionalized hybrid nanocomposite (HyNC) embedded into the PCM has effectively created the densely packed network of thermal interfaces in the PCM matrix layers. The experimental results suggest that, the incorporation of the HyNC has enabled the HNPCM to exhibit improved thermal conductivity (0.347 W/m K), congruent phase transition temperature (freezing: 33.53ᵒC, melting: 35.32 ᵒC), high latent heat capacity (freezing: 109.05 kJ/kg, melting: 109.14 kJ/kg) and considerable reduction in (freezing time: 21.2%, melting time: 29.2%). The improved thermal properties being achieved facilitate the HNPCM to be considered as a viable thermal storage material for high performance and sustainable building cooling and heating applications.Item Dimethyl Adipate-Based Microencapsulated Phase Change Material with Silica Shell for Cool Thermal Energy Storage(Springer, 2020-11) Parameshwaran, R.Phase change materials (PCM) have the ability to store and release thermal energy. Encapsulation of these energy storage materials overcomes the difficulties that can enable them for a broad range of applications. In the present study, microencapsulation of dimethyl adipate into silica shell was carried through interfacial hydrolysis and polycondensation method. The prepared microencapsulated phase change materials (MPCM) were characterised using a field emission scanning electron microscope, have shown good sphericity with an average particle size of 596 nm. The chemical structure of MPCM obtained using Fourier transform infrared spectroscopy has exhibited good chemical stability between shell and core materials. Latent heat of enthalpy measured using differential scanning calorimetry was around 24 kJ/kg with onset melting and end set melting as 7.33 °C and 11.97 °C, respectively. Furthermore, thermo-gravimetric analysis studies have shown that MPCM exhibited end set temperatures as 180 °C. Due to the inorganic shell coating over the PCM droplets, MPCM has shown an increase in thermal stability. These properties make MPCM as a viable candidate for cool thermal energy storage applications.Item Solar thermal energy storage for heating applications — A review(IEEE, 2016) Parameshwaran, R.Rise in energy demands and the need to curb carbon emissions has made proliferation of conventional fuels unviable, leading towards the search for alternative energy sources. With a surplus of sunlight reaching the earth every day, solar energy is an immediate renewable alternative to be considered for satisfying the end-user demand requirements. However, generation using solar energy poses its own challenges such as low energy density, fluctuations in energy generation, and mismatch in supply-demand, making it impracticable. In this paper, recent developments in solar thermal and solar photovoltaic systems utilizing thermal energy storage (TES) for heating applications have been reviewed and presented. A general trend in improvements in performance and efficiencies of the solar thermal systems were observed by integrating them with the TES modules. Furthermore, it is suggested that, research in terms of materials suitable for solar thermal storage and design of thermal storage systems is necessary in achieving cost efficient solar-TES systems with enhanced performance for a variety of heating applications.Item Experimental Study on PCM-Based External Wall Cladding for Energy Efficient Buildings(Springer, 2020-01) Parameshwaran, R.The present work reports the experimental investigation of the phase change material (PCM) incorporated into the external wall claddings for achieving energy conservation in building through a passive cooling application. Three types of wall claddings of size 458 mm × 458 mm (1.5 ft × 1.5 ft) in dimension were developed in this experimental study. Lauric acid was utilized as the PCM to be incorporated into the wall claddings. Experimental results suggest that the lauric acid exhibited good latent heat potential, congruent phase change processes, and was thermally stable within operating temperature ranges. Furthermore, it was concluded that out of three cladding types being tested, the percentage drop of air temperature was more in composite wall cladding and the percentage drop of heat flux was more in aluminum box cladding with PCM and coarse aggregate. In total, the cladding incorporated with the PCM was found to be the potential candidate for the enhancement of energy efficiency in building through passive thermal storage and cooling load reduction.Item Preparation, thermal and structural properties of n-octadecane/melamine formaldehyde nanocapsules embedded cement mortar for energy storage application in buildings(Elsevier, 2022) Parameshwaran, R.Phase change materials (PCM) integrated into building fabrics plays an important role in achieving energy efficiency in buildings through thermal energy storage. The incorporation of nanotechnology-based heat storage materials into building fabric materials are becoming increasingly popular in recent times. From this perspective, a novel nanoencapsulated PCM (NePCM) embedded cement mortar was developed and its thermal energy storage and structural properties were investigated, experimentally. In-situ polymerization technique was used to prepare the nanocapsule containing n-Octadecane as the PCM and melamine formaldehyde as the shell material. The particle size analysis results reveal that the size of NePCM ranged from 76 nm to 530 nm. The NePCM resulted in an appreciable encapsulation efficiency of 60.14 % with a melting temperature and latent heat of fusion of 26.01 °C and 122.24 kJ/kg, respectively. The NePCM exhibited good chemical and thermal stability. The pure PCM and the NePCM were embedded into cement mortar with varying proportions for the preparation of cube specimens and based on which a comparative study was performed. During curing the cube specimens for 28 days, leakage of the pure PCM from the cement mortar was noticed to some extent. On the other hand, no leakage issues were found in the NePCM embedded cement mortar, as a result of the shell material which protected the PCM from leaking. The PCM and NePCM embedded cement mortar cube specimens exhibited an excellent compressive strength of 56.8 MPa and 48.16 MPa, respectively. However, by increasing to 6 wt% of PCM content in cement mortar, the cube samples of PCM embedded cement mortar compressive strength was reduced to 44.41 %. Thus, the developed NePCM with improved thermal and structural properties can achieve enhanced energy storage and passive cooling in buildings without sacrificing the structural stability.Item Preparation and characterization of microencapsulated organic phase change material for cool thermal energy storage applications(Elsevier, 2022) Parameshwaran, R.In this study, an ester-based phase change material (PCM) was microencapsulated into a melamine formaldehyde shell using in-situ polymerization. The Surface morphology, thermal stability, and phase change properties of the microcapsules were characterized using field-emission scanning electron microscope (FESEM), thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques, respectively. The observed surface morphology reveals that prepared microcapsules shown near-spherical structures with smooth surfaces. The TGA results indicate that the microencapsulated phase change material (MPCM) has on-set and end set degradation temperatures as 110.3 °C and 142 °C, respectively, ensuring good thermal stability of MPCM. The enthalpy of latent heat measured using the DSC technique was around 65 kJ/kg, with onset peak melting at 8.57 °C.Item Nanomaterial-Based PCM Composites for Thermal Energy Storage in Buildings(Springer, 2016-02) Parameshwaran, R.Energy efficiency in buildings is a vital factor to be addressed in every stages of development of building envelopes, since buildings consume almost one-third to one-quarter of energy being produced globally. In the spectrum of techniques available to cater the building cooling and heating load demands, there has been a continuous quest toward latent thermal energy storage (LTES) systems for achieving energy redistribution requirements in buildings. The interesting fact about the LTES systems relies on the phase change materials (PCMs) being used to store and release heat energy depending upon the thermal load demand. A step ahead, the utilization of nanomaterials paves the way for accomplishing enhanced thermal performance of such PCMs on a long run. This chapter is exclusively dedicated to provide better understanding of a variety of nanomaterial-based PCM composites for thermal energy storage and energy efficiency in buildings. This is an ever-growing as well as emerging field of interest to wide scientific and engineering communities globally. The nucleus of this chapter is focused on the enhancement of thermal energy storage capabilities of NanoPCM composites which would contribute for achieving improved energy efficiency in buildings.Item Micro/nanoencapsulation of dimethyl adipate with melamine formaldehyde shell as phase change material slurries for cool thermal energy storage(Elsevier, 2022-06) Parameshwaran, R.The present study reports the encapsulation of dimethyl adipate into a polymer shell using in-situ polymerisation. Surface morphology, crystal structure, chemical stability, and thermal properties are characterised using various analytical methods and experimentally investigated. The surface morphology has shown excellent sphericity with a mean particle diameter of 900 nm. The measured enthalpy was 80.2 J/g, with the onset and peak melting temperatures are 6.4 °C and 9.6 °C, respectively. The calculated specific heat capacities of encapsulated dimethyl adipate are around 1.7 J/g.K and 2.3 J/g.K for solid and liquid states, respectively. Furthermore, thermal cycling performance was obtained as 95.3% after 100 thermal cycles. These capsules dispersed into the base fluid (deionized double distilled water) in appropriate proportions for the preparation of micro/nanoencapsulated phase change material slurries (MNPCMS). The prepared slurries have shown a marginal increase in viscosity compared to the base fluid. Therefore, the test results signified that the prepared MNPCMS can be considered as a potential candidate for cool thermal energy storage applications.Item Energy efficient pumpable cement concrete with nanomaterials embedded PCM for passive cooling application in buildings(Elsevier, 2020) Parameshwaran, R.The growing energy demand and energy requirements in the construction sector have paved way to the development and incorporation of the energy efficient materials and technologies in building envelopes. This research work is aimed at investigating the suitability of a pumpable cement concrete with nanomaterials embedded phase change material (PCN-PCM) for achieving energy efficiency in buildings through passive cooling application. In this work, an attempt was made to mix the flyash and ground-granulated blast-furnace slag (GGBS) as replacement materials for the cement along with the super plasticisers. To this engineered pumpable concrete, different sequential processes of adding the organic PCM (lauryl alcohol) embedded with nanomaterials (ZnO and hybrid Cu-TiO2) have been carried out. The mixing process was then optimised based on the incorporation of the PCM (0% to 20% with incremental steps of 5%) and the nanomaterials (0.01%–0.05% with incremental steps of 0.01%) into the cement concrete. The as-prepared PCN-PCM was characterized and tested from both thermal and structural aspects. The XRD results suggest that, the nanomaterials prepared were highly crystalline, and the adsorption of the Cu nanoparticles on the surface of the TiO2 nanoparticles were significant as observed from the FESEM images. The FTIR results confirm that the PCN-PCM composite were chemically stable for the mix-design combinations. In addition, the as-prepared composite achieved a characteristic compressive strength of 20 MPa, which confirms its structural stability. Furthermore, the experimental results reveal that, the PCN-PCM composite exhibited good latent heat potential by storing thermal energy and thereby; regulated the indoor air temperature of the test room around 24 °C. Based on the aforementioned attributes, the as-prepared PCN-PCM composite is expected to serve as an energy efficient candidate for achieving good thermal storage capabilities and structural integrity through passive cooling in buildings.Item Microencapsulated phase change materials as slurries for thermal energy storage: A review(Elsevier, 2021) Parameshwaran, R.Phase change materials (PCM) have the potential to store and release large amounts of thermal energy by undergoing phase transitions from solid to liquid. The microencapsulation technique improves chemical stability and enhances the thermal properties of PCMs, thereby implement these materials for a wide range for applications. The dispersion of these materials into a base fluid (carrier fluid) results in a microencapsulated phase change material slurry. The slurry being in a state of flow can store and release energy with minimal temperature rise. This paper reviews the methods available for slurry preparation and discusses the techniques of characterization. In further, the applications of these slurries in the fields of thermal energy storage are also presented.