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

Year 2018, Volume: 31 Issue: 2, 616 - 626, 01.06.2018

Ahmet Öztürk , Mehmet Özalp , Adnan Sözen

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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