Improved Thermophysical Properties of Developed Ternary Nitrate-Based Phase Change Material Incorporated with MXene as Novel Nanocomposites

In this study,nanocomposite of ternary nitrate molten salt induced with MXene is developed.LiNO3-NaNO3-KNO3 with wt%of 35:12:53 and 35:10:55 are produced and doped with MXene in the wt%of 0.2,0.5,1.0,and 1.5.FTIR result indicates the composites had no chemical reaction occurred during the preparation.UV-VIS analysis shows the absorption enhancement with respect to the concentration of MXene.Thermogravimetric analysis(TGA)was used to measure the thermal stability of the LiNO_(3)-NaNO_(3)-KNO_(3) induced with MXene.The ternary molten salts were stable at temperature range of 600–700°C.Thermal stability increases with the addition of MXene.1.5 wt%of MXene doped with LiNO_(3)-NaNO_(3)-KNO_(3) with wt%35:10:55 and 35:12:53,increases the thermal stability from 652.13°C to 731.49°C and from 679.82°C to 684.57°C,respectively.Using thermophysically enhanced molten salt will increase the efficiency of CSP.

An Updated Review on Low-Temperature Nanocomposites with a Special Focus on Thermal Management in Buildings

Buildings contribute to 33%of total global energy consumption,which corresponds to 38%of greenhouse gas emissions.Enhancing building’s energy efficiency remains predominant in mitigating global warming.Advance-ments in thermal energy storage(TES)techniques using phase change material(PCM)have gained much attention among researchers,primarily to minimize energy consumption and to promote the use of renewable energy sources.PCM technology stays as the most promising technology for developing high-performance and energy-efficient buildings.The major drawback of PCM is its poor thermal conductivity which limits its potential use which could be resolved by dispersing conductive nanofillers.The acquired database on synthesis routes,properties,and performance of nano-dispersed phase change materials(NDPCMs)with various techniques presented in the paper should deliver useful information in the production of NDPCMs with desirable characteristics mainly for building construction applications.An outline of contemporary developments and use of NDPCMs as TES medium is delivered.Finally,a brief discussion on challenges and the outlook was also made.In-depth research is needed to explore the fundamental mechanisms behind the enhanced thermal conductivity of NDPCM with nanofillers dispersion and also a thorough investigation on how these mechanisms drive improvement in building performance.

Multi-objective optimization in a finite time thermodynamic method for dish-Stirling by branch and bound method and MOPSO algorithm

There are various analyses for a solar system with the dish-Stirling technology.One of those analyses is the finite time thermodynamic analysis by which the total power of the system can be obtained by calculating the process time.In this study,the convection and radiation heat transfer losses from collector surface,the conduction heat transfer between hot and cold cylinders,and cold side heat exchanger have been considered.During this investigation,four objective functions have been optimized simultaneously,including power,efficiency,entropy,and economic factors.In addition to the fourobjective optimization,three-objective,two-objective,and single-objective optimizations have been done on the dish-Stirling model.The algorithm of multi-objective particle swarm optimization(MO P S O)with post-expression of preferences is used for multi-objective optimizations while the branch and bound algorithm with pre-expression of preferences is used for single-objective and multi-objective optimizations.In the case of multi-objective optimizations with post-expression of preferences,Pareto optimal front are obtained,afterward by implementing the fuzzy,LINMAP,and TOPSIS decision making algorithms,the single optimum results can be achieved.The comparison of the results shows the benefits of MOPSO in optimizing dish Stirling finite time thermodynamic equations.

Preparation,characterization and thermophysical properties investigation of A70/polyaniline nanocomposite phase change material for medium temperature solar applications

The ever-present demand for energy from various application in industrial and domestic processes has led to the consumption of fossil fuel at a rapid rate with adverse effect due to global warming.This study focuses on the thermal energy storage aspect intended for medium temperature applications.A novel composite A70 and PANI was prepared and characterized.The study investigates the composites thermophysical and optical properties.Differential Scanning Calorimetry and Transient Hot Bridge measured thermal storage capacity and thermal conductivity of the composite,respectively.The heat storage capacity of the composite remained stable within 4%whereas a highest rise of 11.96%in thermal conductivity was measured.The composites thermal,chemical,and physical stability were analysed from Thermogravimetric Analyser,Fourier Infrared Transform,and Scanning Electron Microscope,respectively.The composites were thermally stable up to a temperature of 250°C.No chemical reaction occurred between the nanomaterial and base PCM matrix.The microscopic visuals did not show any considerable change in the microscopic structure of the material.In the case of optical properties,the composites showed significant reduction in transmittance of solar spectrum with respect to pure A70.The maximum decrement in transmission was around~89%compared to A70.As the composite prepared were thermally stable till 250°C,hence may be utilized for solar thermal and low concentrated photovoltaic application but not limited to these.