Assessment of heat dissipation performance for nanofluid

A thermal management system that governs the operating temperature is crucial to green energy/power sources. This paper evaluated the feasibility of alumina (Al2O3)/water nanofluid for these cooling systems using an air-cooled heat exchanger for heat dissipation. The Al2O3/water nanofluid was produced by the direct synthesis method at the concentrations of 0.5, 1.0, and 1.5 wt.%. The experiment aimed for measuring the heat dissipation performance at the above weight fractions, fluid flow rates (1.8, 2.1, and 2.4 L/min), and sample temperatures (30, 40, 50, and 60 °C) within the operating range of green energy/power sources. Firstly, the thermal conductivity was measured to prove the enhancement of heat dissipation. After formulating the solid/water parameters and uncertainty analysis, key issues were investigated by controlling the fluid temperatures, flow rates, and weight fractions of nanoparticles. The experiments show that the maximum enhancement of heat exchange compared with distilled water is of 40% at high weight fraction of nanoparticles (1.5 wt.%) and low nanofluid temperature (30 °C). Moreover, the maximum enhanced ratio of pumping power occurs at high temperature of 60 °C and high weight fraction of nanoparticles (1.5 wt.%). Through the experiments, one can obtain the key factors to optimize a thermal management system of green energy/power sources in the near future.

► Al2O3/water nanofluid for an air-cooled heat exchanger of green energies is studied.
► Controlled factors are weight fractions, flow rates, and temperatures of nanofluids.
► Thermal conductivity, heat exchange, pumping power measured under controlled factors.
► High enhanced ratio of heat exchange at low flow rate and low temperature (max. 34%).
► High enhanced ratio of pumping power at high weight fraction and high temperature.