Experimental Investigation of an Al2O3 / Distilled Water Nanofluid Used In the Heat Pipes of Heat Exchangers

Abstract

This study investigates the thermal performance of a heat pipe heat recovery system in air-to-air heat recovery systems using a nanofluid of Al₂O₃ (aluminum oxide) particles and distilled water. The experimental setup used 15 wickless vacuumed copper pipes with a length of 1000 mm, a 10.5 mm inner diameter and a 12 mm outer diameter. The evaporator section consists of 450 mm of heat pipes, the condenser section is 400 mm, and the adiabatic section is 150 mm. In experimental studies, 33% of the evaporator volume of the heat pipes was filled with working fluids. Experiments were carried out at temperatures between 25ºC and 90ºC by using five different cooling air flows (40 g/s, 42 g/s, 45 g/s, 61 g/s and 84 g/s), and two different heating powers (3 kW and 6 kW) for the evaporation section, to determine the heat removed from the condensation section. Experiments were performed for distilled water and Al₂O₃ nanofluid, respectively, and the results were compared with each other. As a result of the experiments, it was observed that using a nanofluid as the working fluid increased the efficiency of the heat pipe. The highest efficiency (η = 59%) was obtained in the experiments carried out using an Al₂O₃ nanofluid at a heating power of 3 kW and an air flow of 112 g/s.

Keywords

• Aluminum oxide,heat pipe,heat recovery,nanofluid

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