Investigation of heat-transfer and fluid dynamic of nanofluids used in heating building

This paper proposes an approach to investigating numerically the behavior of pressure drop and heat transfer flowing through a pipe under constant wall heat flux for copper (II) oxide (CuO), aluminum oxide (Al₂O₃) and silicon dioxide (SiO₂) nanofluids. This approach consists of (a) using the industrial computational fluid dynamics code Ansys CFX 15 for all the simulations reported in this paper, (b) validating the numerical results for the flow of water by comparing the Nusselt number and friction factor in a circular tube used in heating buildings in cold regions and (c) evaluating the use of the three nanofluids in heating buildings. An excellent concordance is obtained with the water- and nanofluid-associated theoretical–empirical heat transfer and pressure drop correlations. Numerical results showed that the use of nanofluids in heating buildings is more efficient. From the thermal condition, the aluminum oxide nanofluid is more effective than the copper (II) oxide and silicon dioxide nanofluids, and the performance index of the aluminum oxide nanofluid is also higher compared with those of copper (II) oxide and silicon dioxide nanofluids. The analysis shows that using nanofluids in heat exchangers could reduce volumetric and mass flow rates. Nanofluids require smaller heating systems, which are able to distribute the same quantity of thermal energy using base fluids. This will also reduce environmental pollutants because smaller heating units use less power.