The thermodynamic relations of exergy efficiency, exergy destruction, thermal and friction entropy generation, Bejan number, and collector efficiency was evaluated experimentally by considering water-based nanodiamond nanofluids circulating in the flat plate collector (FPC) at different particle loadings (ϕ = 0.2% to ϕ = 1.0%) and Reynolds number (5000 – 13000). Additionally, heat transfer, pumping power, friction factor was also evaluated. Thermo-physical properties were measured experimentally and developed regression correlation models to obtain the thermal conductivity, viscosity, specific heat, and density of nanofluids. Experiments indicate that the collector thermal efficiency for water is 53%; however, it is increased to 74% for 1.0% volume concentration of ND/water nanofluid in the FPC. The exergy efficiency is increased to 7.21%; exergy destruction and thermal entropy generation is decreased to 5.14% and 5.81%, and the frictional entropy generation is increased to 23% at 1.0% particle loading and Reynolds number of 10098.1, against the water data. The Nusselt number is enhanced to 32.31% at 1.0% vol. concentration of nanofluid at Reynolds number of 10098.1, with friction factor penalty of 26.77% compared to water. Furthermore, collector cost, energy, and environmental analyses are also performed for water and ND/water nanofluids. Relevant regression equations are proposed to evaluate the Nusselt number and friction factor.

中文翻译：

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在平板太阳能集热器中循环的纳米金刚石/水纳米流体的传热，能量和火用效率提高

通过考虑平板式集热器（FPC）中循环的水基纳米金刚石纳米流体在不同颗粒负载下（ϕ = 0.2％）进行的实验评估了（火用）效率，（火用）破坏，热和摩擦熵产生，贝詹数和收集器效率的热力学关系。至ϕ = 1.0％）和雷诺数（5000 – 13000）。此外，还评估了热传递，泵送功率，摩擦系数。实验测量了热物理性质，并建立了回归相关模型，以获得纳米流体的热导率，粘度，比热和密度。实验表明，集热器对水的热效率为53％。但是，FPC中ND /水纳米流体的体积浓度为1.0％时，它增加到74％。火用效率提高到7.21％；相对于水数据，在1.0％的颗粒负载和10098.1的雷诺数下，火用破坏和热熵的产生分别降低到5.14％和5.81％，摩擦熵的产生增加到23％。体积为1.0％时，Nusselt数增加到32.31％。雷诺数为10098.1时纳米流体的浓度，与水相比，摩擦系数损失为26.77％。此外，还对水和ND /水纳米流体进行了收集器成本，能源和环境分析。提出了相关的回归方程来评价努塞尔数和摩擦系数。体积为1.0％时为31％雷诺数为10098.1时纳米流体的浓度，与水相比，摩擦系数损失为26.77％。此外，还对水和ND /水纳米流体进行了收集器成本，能源和环境分析。提出了相关的回归方程来评价努塞尔数和摩擦系数。体积为1.0％时为31％雷诺数为10098.1时纳米流体的浓度，与水相比，摩擦系数损失为26.77％。此外，还对水和ND /水纳米流体进行了收集器成本，能源和环境分析。提出了相关的回归方程来评价努塞尔数和摩擦系数。