• Energy Research

Energy depletion for the thermal regulation of buildings is a major global concern. Herein, we develop a binary eutectic phase change material (EPCM) consisting of sodium sulphate decahydrate (SSD) and sodium phosphate dibasic dodecahydrate (SPDD) that were modified using borax, carboxymethyl cellulose (CMC), and graphene nanoplatelets (GNP). In the EPCM, SSD, and SPDD were blended at a proportion of 62:38 to obtain a eutectic point of 27.8 °C with a melting enthalpy of 202 J/g. Borax was a nucleating additive to lessen the issue of supercooling, CMC was a thickening agent to ensure phase stability, and GNP was added as a nanomaterial to enhance the thermal behavior of EPCM. Microtopography, chemical stability, optical transmissibility and absorptivity, phase transition characteristic, thermal conductivity, energy storage potential, degree of supercooling, and thermal stability over 200 thermal cycles were tested and determined. Using scanning electron microscopy, the GNP microstructure and its interaction with EPCM are visualized to present the dispersion and formation of the thermal network. The nanocomposite EPCM also has chemical stability, which is aided by a 571% increase in optical absorbance and an 83.8% decrease in transmissibility. With GNP as a nanomaterial, owing to the well-developed thermal network, we achieve a 106% increment in thermal conductance from 0.464 W/m⋅K to 0.956 W/m⋅K; likewise, GNP acts as a conducting binder and enhances the intermolecular interaction leading to an increase in melting enthalpy from 202.4 J/g to 226 J/g. Finally, a numerical simulation of EPCM heating a thermic fluid flowing within a concentric tube with focus on the temperature contour is conducted for elaborating the potential of PCM towards TES systems.

Energy depletion for the thermal regulation of buildings is a major global concern. Herein, we develop a binary eutectic phase change material (EPCM) consisting of sodium sulphate decahydrate (SSD) and sodium phosphate dibasic dodecahydrate (SPDD) that were modified using borax, carboxymethyl cellulose (CMC), and graphene nanoplatelets (GNP). In the EPCM, SSD, and SPDD were blended at a proportion of 62:38 to obtain a eutectic point of 27.8 °C with a melting enthalpy of 202 J/g. Borax was a nucleating additive to lessen the issue of supercooling, CMC was a thickening agent to ensure phase stability, and GNP was added as a nanomaterial to enhance the thermal behavior of EPCM. Microtopography, chemical stability, optical transmissibility and absorptivity, phase transition characteristic, thermal conductivity, energy storage potential, degree of supercooling, and thermal stability over 200 thermal cycles were tested and determined. Using scanning electron microscopy, the GNP microstructure and its interaction with EPCM are visualized to present the dispersion and formation of the thermal network. The nanocomposite EPCM also has chemical stability, which is aided by a 571% increase in optical absorbance and an 83.8% decrease in transmissibility. With GNP as a nanomaterial, owing to the well-developed thermal network, we achieve a 106% increment in thermal conductance from 0.464 W/m⋅K to 0.956 W/m⋅K; likewise, GNP acts as a conducting binder and enhances the intermolecular interaction leading to an increase in melting enthalpy from 202.4 J/g to 226 J/g. Finally, a numerical simulation of EPCM heating a thermic fluid flowing within a concentric tube with focus on the temperature contour is conducted for elaborating the potential of PCM towards TES systems.

Rapid growth in industrialization has led to high dependency of reliable electric power source for its operation. On the contrary, thermal power plants expel pollutants consisting of hazardous gases that result in degradation of environment and ecosystem. Thus, utmost importance is to generate clean and efficient energy from power plant. This current article resolves the problem of sustainable power production using coal-based thermal power plants, by integrating gasification technologies to the system. The performance of thermal power plant in terms of emission is numerically analyzed with varying gasifier pressure, air-fuel ratio, steam-fuel ratio and flue gas-fuel ratio. Numerical simulation of the gasification cycle with varying parameters is carried out using MATLAB. Optimum performance at gasifier pressure of 2 bar and the steam-fuel ratio of 0.25 was observed with relative air-fuel of 0.075. With increasing flue gas-fuel ratio from 0.25 to 1.00, although the mole fractions of components of syngas don’t differ much, the heating value and cold-gas efficiency of syngas produced decreases for each fuel. Considering the emissions, simulated results present co-gasification as better option over conventional systems. A reduction of two-third in kg of CO2 released per kg of fuel was observed with almost three-fourth decrement in kg of CO2 per kWh of power produced. Also, zero SOx and NOx emissions were observed compared to coal based thermal power plants. It is noted that optimum performance of gasification system at gasifier pressure of 2 bar, air-fuel ratio of 0.1, steam-fuel ratio of 0.25 and flue gas-fuel ratio of 1.00. The proposed cycle presents itself suitable for further research and its application to coal based thermal power plants, providing potential towards supplementary power generation and cleaner exhaust. This research would also significantly contribute to achieve sustainable development goals.

Rapid growth in industrialization has led to high dependency of reliable electric power source for its operation. On the contrary, thermal power plants expel pollutants consisting of hazardous gases that result in degradation of environment and ecosystem. Thus, utmost importance is to generate clean and efficient energy from power plant. This current article resolves the problem of sustainable power production using coal-based thermal power plants, by integrating gasification technologies to the system. The performance of thermal power plant in terms of emission is numerically analyzed with varying gasifier pressure, air-fuel ratio, steam-fuel ratio and flue gas-fuel ratio. Numerical simulation of the gasification cycle with varying parameters is carried out using MATLAB. Optimum performance at gasifier pressure of 2 bar and the steam-fuel ratio of 0.25 was observed with relative air-fuel of 0.075. With increasing flue gas-fuel ratio from 0.25 to 1.00, although the mole fractions of components of syngas don’t differ much, the heating value and cold-gas efficiency of syngas produced decreases for each fuel. Considering the emissions, simulated results present co-gasification as better option over conventional systems. A reduction of two-third in kg of CO2 released per kg of fuel was observed with almost three-fourth decrement in kg of CO2 per kWh of power produced. Also, zero SOx and NOx emissions were observed compared to coal based thermal power plants. It is noted that optimum performance of gasification system at gasifier pressure of 2 bar, air-fuel ratio of 0.1, steam-fuel ratio of 0.25 and flue gas-fuel ratio of 1.00. The proposed cycle presents itself suitable for further research and its application to coal based thermal power plants, providing potential towards supplementary power generation and cleaner exhaust. This research would also significantly contribute to achieve sustainable development goals.

Phase Change Materials (PCMs) enable thermal energy storage in the form of latent heat during phase transition. PCMs significantly improve the efficiency of solar power systems by storing excess energy, which can be used during peak demand. Likewise, they also contribute to reduced overall energy demand through passive thermal regulation. Nonetheless, thermal energy charging and discharging are restricted due to the low conducting nature of the energy storage medium. Various research investigations are being carried out to improve the thermal characteristics of PCMs through techniques such as a) dispersion of nanoparticles, b) inserting fins, and c) cascading PCMs. Among the techniques mentioned above, the dispersion of nanoparticles is reliable and economically viable. These materials are so-called nano-enhanced PCMs (NePCMs) that facilitate the charging and discharging processes of the thermal energy storage (TES) units owing to their improved thermo physical properties and long term stability. This paper presents a comprehensive review with implications and inferences on research conducted using nano-enhanced phase change materials (NePCMs) in recent years. Initially, the article discusses the highly preferred synthesis methods of NePCMs in addition to its morphological and thermophysical characterization techniques. Then, an acute focus on the impact of distinct dimensional nano additives like zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) on inclusion with PCMs are elaborately discussed. A deep discussion on emerging and hybrid nanoparticles dispersed PCMs with emphasis on a) the interaction mechanism of nanoparticle & phase change material (PCM) and b) influences on enhancing the thermophysical properties (melting point, thermal conductivity, latent heat capacity, thermal diffusivity, and thermal stability) of NePCMs are discussed. Indeed, including nanomaterials within the PCM matrix resulted in variations in thermal conductivity and heat storage ...