Eldesoukey Ayman, Hassan Hamdy
Energy Resources Engineering Department, Egypt-Japan University of Science and Technology (E-JUST), Alexandria, Egypt.
Mechanical Engineering Department, Faculty of Engineering, Kafrelsheikh University, Kafr el-Sheikh, Egypt.
Environ Sci Pollut Res Int. 2022 Oct;29(49):74242-74263. doi: 10.1007/s11356-022-21015-1. Epub 2022 May 30.
A huge number of chimneys all over the world utilized in many industrial applications and applications like restaurants, homes, etc. contribute badly on the global warming and climate change due to their waste heat. So, in this paper, the performance of thermoelectric generator (TEG) cooled by microchannel heat spreader having nanofluid and used for waste heat recovery from vertical chimney is investigated. Using heat spreader with microchannel cooling system increases the output TEG power compared to natural convection cooling system. In this paper, the impact of microchannel sizes, using nanofluid and heat spreader with different sizes on the TEG performance and cooling, is considered. Three-dimensional mathematical models including TEG, microchannel, nanofluid, and heat spreader are presented and solved by Ansys Fluent software utilizing user-defined memory, user-defined function, and user-defined scalar. All TEG effects (Joule, Seebeck, and Thomson) are considered in TEG model. Results indicate that TEG power rises with increasing the heat spreader and microchannel sizes together. Increasing microchannel and heat spreader sizes four times of TEG size raises the TEG output power by 10%. This also achieves the maximum cooling system efficiency of 88.9% and the maximum net output power. Microchannel heat spreader cooling system raises the system (TEG power-pumping power) net power by 125.2% compared to the normal channel and decreases the required cooling fluid flow rate. Utilizing copper-water and AlO-water nanofluids rises maximally the TEG output power by 14% and 4%, respectively; however, it increases the pumping power. Moreover, using nanofluids increases the net output power at low Reynolds number and decreases it at higher Reynolds number.
全球大量的烟囱被用于许多工业应用以及餐厅、家庭等场所，因其废热对全球变暖和气候变化造成了严重影响。因此，本文研究了由具有纳米流体的微通道散热器冷却、用于从垂直烟囱回收废热的热电发电机（TEG）的性能。与自然对流冷却系统相比，使用带有微通道冷却系统的散热器可提高TEG的输出功率。本文考虑了微通道尺寸、使用纳米流体以及不同尺寸的散热器对TEG性能和冷却的影响。通过Ansys Fluent软件利用用户定义内存、用户定义函数和用户定义标量，建立并求解了包括TEG、微通道、纳米流体和散热器的三维数学模型。在TEG模型中考虑了所有TEG效应（焦耳效应、塞贝克效应和汤姆逊效应）。结果表明，TEG功率随着散热器和微通道尺寸的同时增加而上升。将微通道和散热器尺寸增加到TEG尺寸的四倍，可使TEG输出功率提高10%。这还实现了88.9%的最大冷却系统效率和最大净输出功率。与普通通道相比，微通道散热器冷却系统使系统（TEG功率-泵浦功率）净功率提高了125.2%，并降低了所需的冷却液流速。使用铜水和氧化铝水纳米流体分别使TEG输出功率最大提高14%和4%；然而，这会增加泵浦功率。此外，使用纳米流体在低雷诺数时会增加净输出功率，而在高雷诺数时会降低净输出功率。
