https://orcid.org/0000-0001-8612-2233
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ABSTRACT
In view of the current global energy situation, increasing the efficiency of heat exchangers can contribute significantly to reducing energy consumption and greenhouse gas emissions. In this study, the effects of nanofluids (SiO2/Water) prepared at different fluid flow rates and different volumetric concentrations (vol.%0.1-0.2-0.3) on three heat exchangers (Shell and Tube, Double Pipe, Plate) with the same capacity were investigated experimentally and statistically. It was concluded that there was an increase of 47% in effectiveness and 87.3% in NTU value with the increase in the volumetric concentrations of nanofluids and fluid flow rate. With the use of nanofluids, it was observed that entropy production decreased by up to 56.08%. The results obtained were analyzed using Response Surface Methodology (RSM) and mathematical models were created and the prediction capabilities of the models were 98% and above. Entropy minimization was performed using statistical methods and it was statistically determined that plate heat exchangers give better results among heat exchangers with the same capacity. It is concluded that the entropy production is minimum when the fluid flow rate is 2 lpm, the volumetric concentration is 0.3% and a plate heat exchanger is used. This study has provided a different and comprehensive perspective on heat exchangers, and it is thought that it will give many ideas to researchers working in this field.
Nomenclature
| A | = | Area (m2) |
| Cp | = | Specific heat capacity(J/kg.K) |
| k | = | Thermal conductivity (W/m.K) |
| L | = | Length (m) |
| m | = | Mass (kg) |
| = | Mass flow rate (kg/s) | |
| NTU | = | Number of Transfer Unit |
| = | Volumetric flow rate (kg/s) | |
| Q | = | Heat (W) |
| S | = | Entrophy (kJ/kg.K) |
| T | = | Temperature (K) |
| U | = | Overall heat transfer (W/m2K) |
| V | = | Voltage (V) |
| Subscripts | = | |
| c | = | cold |
| h | = | hot |
| out | = | Outlet |
| in | = | Inlet |
| nf | = | Nanofluid |
| np | = | Nanoparticle |
| th | = | Thermal |
| bf | = | Base fluid |
| p | = | Pressure |
| Greek symbols | = | |
| ε | = | Effectiveness |
| μ | = | Dynamic viscosity |
| σ | = | Boltzmann constant |
| ϕ | = | Volumetric Concentration |
| ρ | = | Density(kg/m3) |
| η | = | Efficiency |
Acknowledgements
The author(s) declared no potential conflicts of interest with respect to the research, author-ship, and/or publication of this article.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Notes on contributors
Kadir Gelis
Kadir Gelis is an associate professor at Bolu Abant Izzet Baysal University, Faculty of Engineering, Department of Mechanical Engineering. His interest areas include photovoltaic thermal systems, nanofluids, heat exchangers, fuel cells and energy efficiency, thermal system design and optimization.
Kadir Ozbek
Kadir Ozbek is a research assistant at Bolu Abant Izzet Baysal University, Faculty of Engineering, Department of Mechanical Engineering. His interest areas include photovoltaic thermal systems, nanofluids, heat exchangers, wind turbines, energy efficiency in buildings, mega scale photovoltaic system design.
Musaab Huwaish
Musaab Huwaish is an engineer at the Salah al-Din Governorate Office in Iraq. His areas of interest include mechanical engineering, heat transfer, power plants, etc.