scholarly journals Chemically driven energetic molecular ferroelectrics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yong Hu ◽  
Zhiyu Liu ◽  
Chi-Chin Wu ◽  
Jennifer L. Gottfried ◽  
Rose Pesce-Rodriguez ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Wave ◽  
Energetic Materials ◽  
Electrical Energy ◽  
High Energy ◽  
Specific Power ◽  
Thermal Mass ◽  
Ferroelectric Crystal ◽  
Electron Phonon Interaction ◽  
Imidazolium Cations

AbstractChemically driven thermal wave triggers high energy release rate in covalently-bonded molecular energetic materials. Molecular ferroelectrics bridge thermal wave and electrical energy by pyroelectric associated with heating frequency, thermal mass and heat transfer. Herein we design energetic molecular ferroelectrics consisting of imidazolium cations (energetic ion) and perchlorate anions (oxidizer), and describe its thermal wave energy conversion with a specific power of 1.8 kW kg−1. Such a molecular ferroelectric crystal shows an estimated detonation velocity of 7.20 ± 0.27 km s−1 comparable to trinitrotoluene and hexanitrostilbene. A polarization-dependent heat transfer and specific power suggests the role of electron-phonon interaction in tuning energy density of energetic molecular ferroelectrics. These findings represent a class of molecular ferroelectric energetic compounds for emerging energy applications demanding high power density.

scholarly journals Numerical Evaluation of a HVAC System Based on a High-Performance Heat Transfer Fluid

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3298
Author(s):  
Gianpiero Colangelo ◽  
Brenda Raho ◽  
Marco Milanese ◽  
Arturo de Risi
Keyword(s):  
Heat Transfer ◽  
High Performance ◽  
Cooling System ◽  
Electrical Energy ◽  
Simulation Software ◽  
Heat Transfer Fluid ◽  
Hvac System ◽  
Dynamic Simulations ◽  
Heating And Cooling ◽  
The University

Nanofluids have great potential to improve the heat transfer properties of liquids, as demonstrated by recent studies. This paper presents a novel idea of utilizing nanofluid. It analyzes the performance of a HVAC (Heating Ventilation Air Conditioning) system using a high-performance heat transfer fluid (water-glycol nanofluid with nanoparticles of Al2O3), in the university campus of Lecce, Italy. The work describes the dynamic model of the building and its heating and cooling system, realized through the simulation software TRNSYS 17. The use of heat transfer fluid inseminated by nanoparticles in a real HVAC system is an innovative application that is difficult to find in the scientific literature so far. This work focuses on comparing the efficiency of the system working with a traditional water-glycol mixture with the same system that uses Al2O3-nanofluid. The results obtained by means of the dynamic simulations have confirmed what theoretically assumed, indicating the working conditions of the HVAC system that lead to lower operating costs and higher COP and EER, guaranteeing the optimal conditions of thermo-hygrometric comfort inside the building. Finally, the results showed that the use of a nanofluid based on water-glycol mixture and alumina increases the efficiency about 10% and at the same time reduces the electrical energy consumption of the HVAC system.

scholarly journals Risk-Averse Scheduling of Combined Heat and Power-Based Microgrids in Presence of Uncertain Distributed Energy Resources

2021 ◽  
Vol 13 (13) ◽  
pp. 7119
Author(s):  
Abbas Rabiee ◽  
Ali Abdali ◽  
Seyed Masoud Mohseni-Bonab ◽  
Mohsen Hazrati
Keyword(s):  
Electrical Energy ◽  
High Energy ◽  
Combined Heat And Power ◽  
Energy Resources ◽  
Distributed Energy Resources ◽  
Solar Pv ◽  
Distributed Energy ◽  
Robust Scheduling ◽  
Battery Energy ◽  
The Impact

In this paper, a robust scheduling model is proposed for combined heat and power (CHP)-based microgrids using information gap decision theory (IGDT). The microgrid under study consists of conventional power generation as well as boiler units, fuel cells, CHPs, wind turbines, solar PVs, heat storage units, and battery energy storage systems (BESS) as the set of distributed energy resources (DERs). Additionally, a demand response program (DRP) model is considered which has a successful performance in the microgrid hourly scheduling. One of the goals of CHP-based microgrid scheduling is to provide both thermal and electrical energy demands of the consumers. Additionally, the other objective is to benefit from the revenues obtained by selling the surplus electricity to the main grid during the high energy price intervals or purchasing it from the grid when the price of electricity is low at the electric market. Hence, in this paper, a robust scheduling approach is developed with the aim of maximizing the total profit of different energy suppliers in the entire scheduling horizon. The employed IGDT technique aims to handle the impact of uncertainties in the power output of wind and solar PV units on the overall profit.

Synthesis, structure and properties of neutral energetic materials based on N-functionalization of 3,6-dinitropyrazolo[4,3-c]pyrazole

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 84760-84768 ◽  
Author(s):  
Yanan Li ◽  
Yuanjie Shu ◽  
Bozhou Wang ◽  
Shengyong Zhang ◽  
Lianjie Zhai
Keyword(s):  
Energy Density ◽  
Energetic Materials ◽  
High Energy ◽  
High Energy Density ◽  
Structure And Properties ◽  
High Energy Density Materials

Various neutral energetic derivatives based onN-functionalization of DNPP were synthesized, which can be used as new high energy-density materials.

scholarly journals Reconstruction of the thermal properties in a wave-type model of bio-heat transfer

2020 ◽  
Vol 30 (12) ◽  
pp. 5143-5167
Author(s):  
Moataz Alosaimi ◽  
Daniel Lesnic ◽  
Jitse Niesen
Keyword(s):  
Heat Transfer ◽  
Physical Properties ◽  
Thermal Wave ◽  
Wave Model ◽  
Temperature Measurements ◽  
Dimensionless Parameters ◽  
Content Type ◽  
Boundary Temperature ◽  
Dimensional Parameters ◽  
Thermo Physical Properties

Purpose This study aims to at numerically retrieve five constant dimensional thermo-physical properties of a biological tissue from dimensionless boundary temperature measurements. Design/methodology/approach The thermal-wave model of bio-heat transfer is used as an appropriate model because of its realism in situations in which the heat flux is extremely high or low and imposed over a short duration of time. For the numerical discretization, an unconditionally stable finite difference scheme used as a direct solver is developed. The sensitivity coefficients of the dimensionless boundary temperature measurements with respect to five constant dimensionless parameters appearing in a non-dimensionalised version of the governing hyperbolic model are computed. The retrieval of those dimensionless parameters, from both exact and noisy measurements, is successfully achieved by using a minimization procedure based on the MATLAB optimization toolbox routine lsqnonlin. The values of the five-dimensional parameters are recovered by inverting a nonlinear system of algebraic equations connecting those parameters to the dimensionless parameters whose values have already been recovered. Findings Accurate and stable numerical solutions for the unknown thermo-physical properties of a biological tissue from dimensionless boundary temperature measurements are obtained using the proposed numerical procedure. Research limitations/implications The current investigation is limited to the retrieval of constant physical properties, but future work will investigate the reconstruction of the space-dependent blood perfusion coefficient. Practical implications As noise inherently present in practical measurements is inverted, the paper is of practical significance and models a real-world situation. Social implications The findings of the present paper are of considerable significance and interest to practitioners in the biomedical engineering and medical physics sectors. Originality/value In comparison to Alkhwaji et al. (2012), the novelty and contribution of this work are as follows: considering the more general and realistic thermal-wave model of bio-heat transfer, accounting for a relaxation time; allowing for the tissue to have a finite size; and reconstructing five thermally significant dimensional parameters.

Preparation of Activated Carbon Derived from Water Hyacinth as Electrode Active Material for Li-Ion Supercapacitor

2020 ◽  
Vol 1000 ◽  
pp. 50-57
Author(s):  
Jagad Paduraksa ◽  
Muhammad Luthfi ◽  
Ariono Verdianto ◽  
Achmad Subhan ◽  
Wahyu Bambang Widayatno ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Water Hyacinth ◽  
Electrode Materials ◽  
Storage System ◽  
Active Material ◽  
Lithium Ion ◽  
High Energy ◽  
Specific Power ◽  
Full Cell ◽  
Lithium Ion Capacitor

Lithium-Ion Capacitor (LIC) has shown promising performance to meet the needs of high energy and power-density-energy storage system in the era of electric vehicles nowadays. The development of electrode materials and electrolytes in recent years has improvised LIC performance significantly. One of the active materials of LIC electrodes, activated carbon (AC), can be synthesized from various biomass, one of which is the water hyacinth. Its abundant availability and low utilization make the water hyacinth as a promising activated carbon source. To observe the most optimal physical properties of AC, this study also compares various activation temperatures. In this study, full cell LIC was fabricated using LTO based anode, and water hyacinth derived AC as the cathode. The LIC full cell was further characterized to see the material properties and electrochemical performance. Water hyacinth derived LIC can achieve a specific capacitance of 32.11 F/g, the specific energy of 17.83 Wh/kg, and a specific power of 160.53 W/kg.

Numerical Study to Analyze the Effects of Hot/Cold Aisle Configurations on Heat Transfer Phenomenon in a Data Center

2013 ◽  
Author(s):  
Kamran Nazir ◽  
Naveed Durrani ◽  
Imran Akhtar ◽  
M. Saif Ullah Khalid
Keyword(s):  
Heat Transfer ◽  
Data Center ◽  
Data Centers ◽  
Cooling System ◽  
Numerical Study ◽  
High Energy ◽  
Research Area ◽  
Transfer Phenomenon ◽  
Heat Transfer Phenomenon ◽  
Active Research

Due to high energy demands of data centers and the energy crisis throughout the world, efficient heat transfer in a data center is an active research area. Until now major emphasis lies upon study of air flow rate and temperature profiles for different rack configurations and tile layouts. In current work, we consider different hot aisle (HA) and cold aisle (CA) configurations to study heat transfer phenomenon inside a data center. In raised floor data centers when rows of racks are parallel to each other, in a conventional cooling system, there are equal number of hot and cold aisles for odd number of rows of racks. For even number of rows of racks, whatever configuration of hot/cold aisles is adopted, number of cold aisles is either one greater or one less than number of hot aisles i.e. two cases are possible case A: n(CA) = n(HA) + 1 and case B: n(CA) = n(HA) − 1 where n(CA), n(HA) denotes number of cold and hot aisles respectively. We perform numerical simulations for two (case1) and four (case 2) racks data center. The assumption of constant pressure below plenum reduces the problem domain to above plenum area only. In order to see which configuration provides higher heat transfer across servers, we measure heat transfer across servers on the basis of temperature differences across racks, and in order to validate them, we find mass flow rates on rack outlet. On the basis of results obtained, we conclude that for even numbered rows of rack data center, using more cold aisles than hot aisles provide higher heat transfer across servers. These results provide guidance on the design and layout of a data center.

scholarly journals Perspective on advanced nanomaterials used for energy storage and conversion

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hsuanyi Huang ◽  
Rong Li ◽  
Cuixia Li ◽  
Feng Zheng ◽  
Giovanni A. Ramirez ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Microbial Fuel Cells ◽  
Communication Systems ◽  
Sustainable Energy ◽  
Ambient Pressure ◽  
Electrical Energy ◽  
High Energy ◽  
Solid Oxide ◽  
Energy Storage And Conversion ◽  
Energy Materials

Abstract To drive the next ‘technical revolution’ towards commercialization, we must develop sustainable energy materials, procedures, and technologies. The demand for electrical energy is unlikely to diminish over the next 50 years, and how different countries engage in these challenges will shape future discourse. This perspective summarizes the technical aspects of nanomaterials’ design, evaluation, and uses. The applications include solid oxide fuel cells (SOFCs), solid oxide electrolysis cells (SOEC), microbial fuel cells (MFC), supercapacitors, and hydrogen evolution catalysts. This paper also described energy carriers such as ammonia which can be produced electrochemically using SOEC under ambient pressure and high temperature. The rise of electric vehicles has necessitated some form of onboard storage of fuel or charge. The fuels can be generated using an electrolyzer to convert water to hydrogen or nitrogen and steam to ammonia. The charge can be stored using a symmetrical supercapacitor composed of tertiary metal oxides with self-regulating properties to provide high energy and power density. A novel metal boride system was constructed to absorb microwave radiation under harsh conditions to enhance communication systems. These resources can lower the demand for petroleum carbon in portable power devices or replace higher fossil carbon in stationary power units. To improve the energy conversion and storage efficiency, we systematically optimized synthesis variables of nanomaterials using artificial neural network approaches. The structural characterization and electrochemical performance of the energy materials and devices provide guidelines to control new structures and related properties. Systemic study on energy materials and technology provides a feasible transition from traditional to sustainable energy platforms. This perspective mainly covers the area of green chemistry, evaluation, and applications of nanomaterials generated in our laboratory with brief literature comparison where appropriate. The conceptual and experimental innovations outlined in this perspective are neither complete nor authoritative but a snapshot of selecting technologies that can generate green power using nanomaterials.

Second Law Analysis of Tree-Shaped Fins for the Heat Transfer Enhancement in a PCM Thermal Storage System

2013 ◽  
Author(s):  
Adriano Sciacovelli ◽  
Elisa Guelpa ◽  
Vittorio Verda
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Heat Transfer Enhancement ◽  
Solidification Rate ◽  
High Energy ◽  
Second Law ◽  
Transfer Enhancement ◽  
Energy Storage Devices ◽  
Second Law Analysis ◽  
Melting And Solidification

Latent heat thermal energy storage (LHTES) systems based on phase change materials (PCMs) are a promising option to be employed as effective energy storage devices. PCM allows one to achieve high energy storage density and almost constant temperature energy retrieval, however LHTES systems performance is limited by poor thermal conductivity of the PCMs which leads to unacceptably low melting and solidification rates. Thus, heat transfer enhancement techniques are required in order to obtain acceptable melting and solidification rates. The preliminary design of a shell-and-tube LHTES unit is investigated by means of computational fluid-dynamics (CFD). Three different fin designs are considered: a conventional radial fin, a constructal Y-shaped fin design and a non-constructal Y-shaped configuration previously investigated by the authors. The performances of each fin configuration are evaluated by means of a Second-law analysis. Moreover, local and global entropy generation rates are analyzed in order to show the main source of thermodynamic irreversibilities occurring in the system. The analysis indicates that solidification rate is significantly enhanced when Y-shaped fins are adopted in the LHTES unit, however the constructal Y-shaped geometry is not optimal since further improvements can be achieved by means of a Y-shaped fins with elongated secondary branches.

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