Journal of Thermal Engineering最新文献_第9页

Effect of module operating temperature on module efficiency in photovoltaic modules and recovery of photovoltaic module heat by thermoelectric effect 光伏组件中组件工作温度对组件效率的影响以及热电效应对光伏组件热量的回收

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-27 DOI: 10.18186/thermal.1243519

Ramazan KAYABAŞI1, Metin Kaya

{"title":"Effect of module operating temperature on module efficiency in photovoltaic modules and recovery of photovoltaic module heat by thermoelectric effect","authors":"Ramazan KAYABAŞI1, Metin Kaya","doi":"10.18186/thermal.1243519","DOIUrl":"https://doi.org/10.18186/thermal.1243519","url":null,"abstract":"One of the parameters affecting the efficiency of photovoltaic (PV) modules and PV systems is the temperature. The factors that increase the temperature in PV modules cause loss of efficiency. In this study, experiments have been conducted with the aim of re ducing the module temperature. For this purpose, four polycrystalline and four monocrystalline PV modules, all with the same features, were used. A pair of polycrystalline and monocrystalline modules were used as reference modules. The aim of this study is to reduce the operating temperature of the modules, while also decreasing the transient temperature fluctuations in the system, in order to prevent the loss of efficiency. For this reason, current, voltage and power values of PV modules have been examined and the relationship between these values and module temperature has been explained. As a result, temperature values were measured at 30-80°C in reference modules, 30-50°C in heat pipe modules, 30-37°C in modules using heat pipes and phase-changing material, and 30-66°C in modules using phase-changing material with flexible surfaces. If the PV module operating temperature is increased by 35°C, the module efficiency decreases by 10%. Heat pipe and PCM balance the temperature in PV/T/PCM monocrystalline and polycrystalline modules. In PV/T/PCM modules, efficiency loss caused by temperature increase is 1%. In addition, electrical energy is produced from the heat accumulated on the surface of the PV module by means of Thermoelectric Generator (TEG). When the temperature difference between the surfaces is 15°C, the naturally cooled TE provides 0.45V energy output, while the forced-cooled TEG provides 0.97V energy output. As the temperature gap between the surfaces increases, the voltage and current values of the TEG also increase. Briefly, TEG’s power values increase up to 5W depending on the temperature gap between surfaces.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43350372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Field-synergy and nanoparticle’s diameter analysis on circular jet impingement using three oxide–water-based nanofluids 三种氧化物-水性纳米流体环形射流冲击的场协同效应和纳米颗粒直径分析

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-27 DOI: 10.18186/thermal.1243512

A. Datta, P. Halder

{"title":"Field-synergy and nanoparticle’s diameter analysis on circular jet impingement using three oxide–water-based nanofluids","authors":"A. Datta, P. Halder","doi":"10.18186/thermal.1243512","DOIUrl":"https://doi.org/10.18186/thermal.1243512","url":null,"abstract":"The field synergy study is carried out using three oxide nanofluids impinging circular jet on the horizontal circular disc to analyse the synergetic interaction of cooling processes between temperature and flows fields. The h eat transfer effect o f the nanofluid is examined by rising the Reynolds number and the nanoparticle concentration depending on field synergy number. For jet impinged cooling process, the scale of synergy between the nanofluid flow speed and temperature is decayed with the increase of Reynolds number. Hence, it is contributed to a lower heat transfer efficiency of the nanofluid. Whe reas, the scale of synergy between the nanofluid flow speed and temperature can be enhanced by rising the particle concentration. Thus, the heat transfer efficiency of the nanofluid is increased. Analysis showed that Al2O3 nanofluid has the maximum relative field synergy among selected three oxide nanofluids. It is evident that the nanoparticle concentration, nanoparticle material and Reynolds number have significant effect on the heat transfer augmentation. In addition, the study is explored by varying jet-disk spacing. Moreover, the investigation has shown that the reducing heat transfer effect for the materials is Al2O3, CuO and TiO2 subsequently. It is revealed that the heat enhancement is higher for smaller nanoparticle’s diameter (i.e., 20 nm) than bigger nanoparticle’s diameter (i.e., 80 nm) of the same material.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41480588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Heat transfer performance of nanofluids in heat exchanger: a review 纳米流体在换热器中的换热性能研究进展

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-27 DOI: 10.18186/thermal.1243398

R. Barai, Devesh Kumar, A. Wankhade

{"title":"Heat transfer performance of nanofluids in heat exchanger: a review","authors":"R. Barai, Devesh Kumar, A. Wankhade","doi":"10.18186/thermal.1243398","DOIUrl":"https://doi.org/10.18186/thermal.1243398","url":null,"abstract":"Energy is a key aspect of any country’s economic development. Improving heat transfer performance leads to saving energy. Nanotechnology has a key role to play in optimizing heat exchangers. Fluids containing nanosized particles are called nanofluids. Nanofluids have higher thermal conductivity than typical liquids. This paper outlines current research on convective heat transfer performance, thermophysical properties, particle size, and volume concentration effects in nanofluid studies. M easurement m ethods f ort h ermal conductivity and correlations used by earlier researchers to determine thermal conductivity are also encompassed. The main applications of nanofluids as liibricants a nd radiator systems to improve the efficiency of he at removal fr om ve hicle en gines ha ve al so be en emphasized. Results suggest that by using a larger size of particle some drawbacks include particle sedimentation, clogging, erosion, stability, and increasing pressure drop. Enhancing thermal conductivity with optimum volume concentration. Improving the efficiency of heat exchange systems is one of the possible ways to reduce energy consumption. The need for optimum concentration of nanofluids is required. The Problem of stability, corrosion, and erosion arrived by increasing the volume concentration of nanoparticles in a nanofluid.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46587250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Design and analysis of an alkaline fuel cell 碱性燃料电池的设计与分析

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-27 DOI: 10.18186/thermal.1243498

M. Azzam, Zabayyan Qaq, M. Orhan

{"title":"Design and analysis of an alkaline fuel cell","authors":"M. Azzam, Zabayyan Qaq, M. Orhan","doi":"10.18186/thermal.1243498","DOIUrl":"https://doi.org/10.18186/thermal.1243498","url":null,"abstract":"This study provides a step-by-step, up-to-date fuel cell fundamentals, thermodynamic and electrochemical principles, and system evaluation factors via a case study of a 10-kW alkaline fuel cell designed to operate in space applications. The system also produces 100 kg of pure water and 5.5 kW of heat. The system is modelled using MATLAB and ANSYS Fluent. Then, the model is verified with theoretical and experimental results from the literature. A parametric study of various design and operating parameters, and material selection is carried out to optimize the overall performance. A net output voltage of 0.8 V is obtained at 150 mAcm-2 current density, which yields an overall efficiency of 75%. The results indicate that increasing the electrolyte thickness or operating temperature results in a lower net voltage output. Additionally, improving the performance of a fuel cell through the bipolar plate can be achieved by understanding the contribution of different parameters towards minimizing the pressure drop across the bipolar plate. It is found that implementing an optimized selection of fluid flow rate, channel width, channel depth, number of channels and current density minimize the pressure drop throughout the bipolar plate. Relative humidity has a significant effect on the pressure drop. Results indicate that increasing the relative humidity consequentially rises the pressure drop. Finally, the CFD simulation illustrates that the end-zones in the bipolar plate accumulates fluid due to the nature of stagnation at those locations. Thus, total pressure at those locations is the highest. One of the major contributions here is studying the effect of KOH concentration on the performance of the AFC at different operating temperatures. In addition, a wide range of design and operating parameters were analysed to understand their effect on the overall performance of the fuel cell.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49304593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of different aluminium oxide based nanofluid concentrations on the efficiency of solar water desalination system 不同氧化铝基纳米流体浓度对太阳能海水淡化系统效率的影响

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-26 DOI: 10.18186/thermal.1242844

Ajit Katiyar, N. Gupta

引用次数: 0

Optimization of energy and exergy parameters for a conceptual after burning turbojet engine 概念型涡喷发动机的能量和火用参数优化

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-26 DOI: 10.18186/thermal.1242919

H. Aygun

{"title":"Optimization of energy and exergy parameters for a conceptual after burning turbojet engine","authors":"H. Aygun","doi":"10.18186/thermal.1242919","DOIUrl":"https://doi.org/10.18186/thermal.1242919","url":null,"abstract":"In this study, parametric cycle analysis of a conceptual turbojet engine with an afterburner (TJEAB) was conducted at sea level conditions-zero Mach. Based on this analysis, exergetic sustainability parameters of TJEAB were scrutinized for military mode (MM) and afterburner mode (ABM). Constitutively, several design parameters of TJEAB were chosen so as to optimize performance and exergetic parameters which consist of specific fuel consumption (SFC), overall efficiency, exergy efficiency, environmental effect factor (EEF) and exergetic sustainability index (ESI). In this context, compressor pressure ratio (CPR), turbine inlet temperature (TIT) were preferred due to high effect of these variables on engine performance. CPR ranges from 4 to 11 whereas TIT varies from 1150 K to 1550 K. According to optimization of performance parameters, minimum SFC was achieved as 28.59 g/kN.s at MM and 43.95 g/kN.s at ABM. On the other hand, maximum overall efficiency is determined as to be 13.07 % at MM and to be 8.5 % at ABM. As for exergetic parameters, exergy efficiency was calculated as maximum with 30.85 % at MM and 23.2 %at ABM. Finally, maximum exergetic sustainability index of TJEAB was computed as 0.446 at MM and 0.269 at ABM. It is thought that energetic and exergetic parameters analyzed in this analysis could guide in designing turbojet engines in terms of lower fuel consumption thereby environmental-benign.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45153111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparative analysis and optimization of thermodynamic behavior of combined gas-steam power plant using grey-taguchi and artificial neural network 基于灰田口法和人工神经网络的燃气-蒸汽联合电厂热力行为对比分析与优化

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-26 DOI: 10.18186/thermal.1242832

K. Madan, O. Singh

{"title":"Comparative analysis and optimization of thermodynamic behavior of combined gas-steam power plant using grey-taguchi and artificial neural network","authors":"K. Madan, O. Singh","doi":"10.18186/thermal.1242832","DOIUrl":"https://doi.org/10.18186/thermal.1242832","url":null,"abstract":"In the published studies, to the best of the authors’ understanding, the grey Taguchi-based statistical technique has not been applied for the optimization of combined gas-steam power plants. In view of this, seven essential input parameters namely compressor inlet air temperature, pressure ratio, fuel temperature, volumetric flow rate of fuel, gas turbine maximum temperature, compressor efficiency, and turbine efficiency are chosen with the aim of determining the optimal combination of design variables that maximize the net power generation, thermal efficiency, exergetic effciency, and minimize the specific fuel consumption. Also, the impact weight of each parameter on output indicators has been evaluated. While the Taguchi approach helps to create an orthogonal array of L27 (3^7), the ANOVA method determines the contribution of each input argument on the objective function. Unlike the Taguchi and ANOVA optimization methodology, the grey relational analysis is performed to transform the multi-objective function into a single objective by way of estimating its grey relational grade. The most favorable combination of input parameters is determined as A1B1C1D1E3F3G3 and under this state, the optimum values of power generation, thermal efficiency, exergetic efficiency, and specific fuel consumption are found to be 259911 kW, 64.9 %, 66.27 %, and 0.1839 kg/kWh respectively. Moreover, the contribution ratio on the output characteristic of the combined cycle is found to be maximum for turbine efficiency (42.41 %) and minimum for fuel temperature (0.59 %). The effectiveness of the grey-Taguchi method is acknowledged and validated using an artificial neural network technique in MATLAB.","PeriodicalId":45841,"journal":{"name":"Journal of Thermal Engineering","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48676338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A sensitivity study for n similar partly enclosed with photovoltaic thermal flat plate collectors having series connection n个相似部分封闭串联光伏热平板集热器的灵敏度研究

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-26 DOI: 10.18186/thermal.1242825

Anuj Raturi, R. Patel, D. Singh

引用次数: 0

Performance improvement of shell and tube heat exchanger by using Fe3O4/water nanofluid Fe3O4/水纳米流体对管壳式换热器性能的改善

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-20 DOI: 10.18186/thermal.1239793

Saad M. Najim, A. Hussein, S. Danook

引用次数: 0

Buoyancy force and magnetic field effects on laminar vortex breakdown and fluid layers 浮力和磁场对层流涡破裂和流体层的影响

IF 1.1

Journal of Thermal Engineering Pub Date : 2023-01-11 DOI: 10.18186/thermal.1232431

B. Mahfoud, M. Moussaoui

引用次数: 1