Faculty Publications
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Item Phase change materials in chemical and process engineering(Elsevier, 2023) Chavan, S.; Manickam, M.; Arumuga Perumal, A.P.; Gumtapure, V.This chapter is concerned with phase change materials in chemical and process engineering. Industrial waste heat recovery is explored as a source of heating and cooling with the application of phase change materials, which is well known. Consequently, heat transformation technologies are presented in detail along with their technical and economic potentials. Initially, utilization of phase change materials in process industries is discussed, which covers on-site and off-site industrial applications. The concept of on-site and off-site thermal energy utilization is well defined. The large amount of industrial waste heat is generated, which can be stored in the phase change materials, and it can be transported to the place where there is energy requirement in particular. Industries such as metal manufacturing, nonmetal manufacturing, chemicals and chemical products, pulp, and food processing industries are the main focuses of the present study. All the technical aspects are discussed in detail with respect to the future scope of phase change materials with thermal energy storage systems. Thermal energy utilization using phase change materials for chemical process industries also has great potentiality for various applications such as thermal fluid heating systems, gas-fired systems, and solar heating systems, which are also discussed. A comprehensive study has been carried out for potential usage of phase change materials for various manufacturing and process engineering applications. © 2023 Elsevier Ltd. All rights reserved.Item Cooling packing and cold energy storage(Elsevier, 2023) Chavan, S.; Manickam, M.; Arumuga Perumal, A.P.; Gumtapure, V.This chapter is divided into two parts: first part discusses about cooling packing applications of phase change materials, and second part discusses about cold thermal energy storage application of PCM. Consequently, methods of thermal energy storage are briefly explained, specifically for cooling packing applications along with present challenges of the technology. The second part of the chapter discusses in brief about cold thermal energy storage specifically basic working principle, loading of cold thermal energy storage for operational purposes CTES in selecting and characterizing storage media, water versus ice thermal energy storage, PCM used for cold thermal storage, advantages, disadvantages, and finally, battery thermal management system in electric vehicle are discussed in brief with updated knowledge in the field of real-time application. © 2023 Elsevier Ltd. All rights reserved.Item Influence of Incorporating Phase Change Materials on Cementitious System—A Review(Springer Science and Business Media Deutschland GmbH, 2021) Snehal, K.; Das, B.B.Phase change materials (PCMs) are gaining more attention in achieving the sustainability and are being widely adopted as a green building material because of their exclusive ability to store latent heat of thermal energy. PCMs have a capacity to minimize the energy loads and to provide thermal comforts in building infrastructures by its iterative cycle of absorbing and releasing the heat energy. The potential need for manipulating the heating and cooling effect in buildings is significantly increasing especially in temperature fluctuating and varied climatic regions. It is for this one of the significant reasons, PCMs are getting pronounced interest by the research fraternity in the development of a thermally effective PCM-based construction material. In this paper, attempts were made to compile the data reported by the previous researchers on the influence of incorporating PCMs in the engineering properties of cementitious system such as slump, compressive strength, flexural strength, density, porosity, water absorption, shrinkage, durability, heat of hydration, specific heat capacity and thermal conductivity. This paper also discusses the most favorable content of PCM addition and effective methods of incorporating PCMs in the cementitious system. © 2021, Springer Nature Singapore Pte Ltd.Item Numerical Study of PCM-Based Energy Storage System Using Finite Difference Method(Springer Science and Business Media Deutschland GmbH, 2024) Abhijith, C.; Maniyeri, R.Energy storage systems incorporating phase change material (PCM) are becoming the answer to intermittent energy availability in the area of solar cooking vessels and solar room heating systems. These thermal energy storage systems are efficient, reliable and can reduce running costs and investments. The present work investigates the melting of n-octadecane using enthalpy formulation method by using finite difference method-based discretization. Accordingly, a numerical model is developed in MATLAB which is validated first by comparing with previous works. Further using the developed model studies on wall materials, thickness, different PCMs and temperatures are carried out. It is found that metal containers with higher thermal conductivities provided significant boost in energy storage. The increased thickness of walls adds significant change only if containers are of lower thermal conductivity such as steel. Different PCMs are analysed, and their operating temperature and energy storage capabilities are studied. In addition, enthalpy equation in cylindrical coordinates is solved since practical PCM storages are commonly cylindrical in shape. At the end, the numerical results are compared with an experimental case with paraffin wax as PCM. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2024.Item A Computer Aided Cooling Curve Analysis method to study phase change materials for thermal energy storage applications(Elsevier Ltd, 2016) Sudheer, R.; Prabhu, K.N.The suitability of a simple Computer Aided Cooling Curve Analysis (CACCA) technique for characterizing thermal energy storage phase change materials (PCM) was proposed in the present work. Two modes of CACCA, namely, Newtonian and Fourier techniques were used to predict the phase transition temperatures, the latent heat of fusion and thermal diffusivities of PCMs. Solidification of potassium nitrate and zinc-8% aluminium alloy (ZA8) was studied using CACCA method. These PCMs were chosen to demonstrate the ability of the proposed technique to characterize PCMs freezing at a single temperature as well as over a range of temperatures. CACCA method showed that potassium nitrate and ZA8 are suitable candidate materials for TES applications operating at 300-350 °C and 350-450 °C respectively. © 2015 Elsevier Ltd.Item Memory type switching behavior of ternary Ge20Te80-xSnx (0 x 4) chalcogenide compounds(Institute of Physics Publishing michael.roberts@iop.org, 2016) Fernandes, B.J.; Sridharan, K.; Pumlianmunga, P.; Ramesh, K.; Udayashankar, N.K.Chalcogenide compounds have gained huge research interest recently owing to their capability to transform from an amorphous to a crystalline phase with varying electrical properties. Such materials can be applied in building a new class of memories, such as phase-change memory and programmable metallization cells. Here we report the memory type electrical switching behavior of a ternary chalcogenide compound synthesized by doping Tin (Sn) in a germanium-telluride (Ge20Te80) host matrix, which yielded a composition of Ge20Te80-xSnx (0 x 4). Results indicate a remarkable decrease in the threshold switching voltage (V T) from 140 to 61 V when the Sn concentration was increased stepwise, which is attributed to the domination of the metallicity factor leading to reduced amorphous network connectivity and rigidity. Variation in the threshold switching voltage (V T) was noticed even when the sample thickness and temperature were altered, confirming that the memory switching process is of thermal origin. Investigations using x-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed the formation of a crystalline channel that acts as the conduction path between the two electrodes in the switched region. Structural and morphological studies indicated that Sn metal remained as a micro inclusion in the matrix and hardly contributed to the rigid amorphous network formation in Ge20Te80-xSnx. Memory type electrical switching observed in these ternary chalcogenide compounds synthesized herein can be explored further for the fabrication of phase-change memory devices. © 2016 IOP Publishing Ltd.Item Crystallization kinetics of Sn doped Ge20Te80?xSnx (0 ? x ? 4) chalcogenide glassy alloys(Elsevier Ltd, 2017) Fernandes, B.J.; Naresh, N.; Ramesh, K.; Sridharan, K.; Udayashankar, N.K.Chalcogenide semiconductors have evolved as multifunctional materials due to their fascinating thermal, optical, electrical and mechanical properties. In this report, Ge20Te80?xSnx (0 ? x ? 4) glassy alloys are systematically studied in order to understand the effect of variation of Sn content on the thermal parameters such as glass transition (Tg) onset crystallization (Tc), peak crystallization (Tp), melting temperature (Tm), activation energy of glass transition (Eg), and crystallization (Ec). The values of Eg are calculated from the variation of Tg with the heating rate (?), according to Kissinger and Moynihan model, while the values of Ec are calculated from the variation of Tp with the heating rate (?), according to Kissinger, Takhor, Augis-Bennett and Ozawa model. Thermal stability and glass forming ability (GFA) are discussed for understanding the applicability of the synthesized materials in phase change memory (PCM) applications. Thermal parameters are correlated with the electrical switching studies to get an insight into the phase change mechanism. The results of the calculated thermal parameters reveal that the GFA of the synthesized Ge20Te80?xSnx (0 ? x ? 4) glassy alloys has a synchronous relationship with their thermal properties studied through differential scanning calorimetry, indicating their potential for phase-change memory device applications. © 2017 Elsevier B.V.Item Cooling Curve Analysis of Micro- and Nanographite Particle-Embedded Salt-PCMs for Thermal Energy Storage Applications(Springer New York LLC barbara.b.bertram@gsk.com, 2017) Sudheer, R.; Prabhu, K.N.In recent years, the focus of phase change materials (PCM) research was on the development of salt mixtures with particle additives to improve their thermal energy storage (TES) functionalities. The effect of addition of microsized (50 ?m) and nanosized (400 nm) graphite particles on TES parameters of potassium nitrate was analyzed in this work. A novel technique of computer-aided cooling curve analysis was employed here to study the suitability of large inhomogeneous PCM samples. The addition of graphite micro- and nanoparticles reduced the solidification time of the PCM significantly enhancing the heat removal rates, in the first thermal cycle. The benefits of dispersing nanoparticles diminished in successive 10 thermal cycles, and its performance was comparable to the microparticle-embedded PCM thereafter. The decay of TES functionalities on thermal cycling is attributed to the agglomeration of nanoparticles which was observed in SEM images. The thermal diffusivity property of the PCM decreased with addition of graphite particles. With no considerable change in the cooling rates and a simultaneous decrease in thermal diffusivity, it is concluded that the addition of graphite particles increased the specific heat capacity of the PCM. It is also suggested that the additive concentration should not be greater than 0.1% by weight of the PCM sample. © 2017, ASM International.Item Assessment of PCM-container interfacial heat transfer using a hot/cold probe technique(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2019) Sudheer, R.; Prabhu, K.N.A novel technique for assessing heat transfer characteristics of salt-based phase change materials (PCM) was proposed here. The method is based on solution to inverse heat conduction problem. Nanoparticles (Graphite, Graphene, and multi wall carbon nanotube [MWCNT]) were dispersed in the PCM (KNO3) to assess their respective influence on heat transfer in the PCM. Graphite added PCM offered highest heat flow values and heating rates, while the pure salt-PCM offered the least. The probe material had a significant influence on the heat transfer rates at the PCM-probe interface. © 2018 Wiley Periodicals, Inc.Item Characterization of linear low-density polyethylene with graphene as thermal energy storage material(Institute of Physics Publishing helen.craven@iop.org, 2019) Chavan, S.; Gumtapure, V.; Arumuga Perumal, D.A.In this work authors reported the preparation and characterization of composite phase change material (CPCM) using the direct-synthesis method by blending the Linear low-density polyethylene (LLDPE) with Carboxyl Functionalized Graphene (f-Gr). LLDPE is selected as base material and f-Gr is dispersed into three different concentrations 1.0, 3.0, and 5.0 wt% and referred as CPCM-1, CPCM-2 and CPCM-3 respectively. Experimental analysis is carried out through Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Differential scanning calorimeter (DSC). The preset study assesses the influences of nanoparticle concentration on thermophysical properties, thermal performance and thermal storage characteristics of CPCMs. Results show that addition of f-Gr improves the thermal conductivity and latent heat of fusion of LLDPE. However, f-Gr slightly reduces the melting temperature and decreased the crystallization temperature. Therefore, this study reveals that f-Gr, addition to LLDPE has substantial potential for improving the thermal energy storage performance. © 2019 IOP Publishing Ltd.