Özet:

In this experimental study, heat transfer experiments were carried out by using pure water and two nanofluids (CuO/Water ve CuO+Fe/Water) whose base fluids are pure water in the heat pipe air-to-air heat exchanger. Nano fluids have a concentration of 2% by weight. The experimental setup consists of two overlapping air ducts. In the middle of the two ducts, there are 5 bundles of copper heat pipes perpendicular to the ducts.. The air passing through the lower duct is heated with 4 units of 1000 Watt heaters. The air in the upper duct cools the heat pipes and condenses the fluid in the heat pipe.. The experiments were carried out at 2 cold air flow rate, 3 hot air flow rate and 2 heating power. In all experiments, it has been observed that nanofluids provide better thermal efficiencies than pure water. Better thermal efficiency values were achieved than the other two fluids in CuO + Fe / Pure water nano fluid experiments. In CuO / Pure water nano fluid experiments, the highest efficiency increase was 68% compared to pure water. In CuO + Fe / Pure water nano fluid experiments the highest efficiency increase was 87% compared to pure water. These recovery rates were realized when the air flows in cold and hot channels were 0.75 m / s and 0.7 m / s, respectively. In addition, the use of CuO / Pure water and CuO + Fe / Pure water nano fluids instead of pure water has reduced the thermal resistance of heat pipes. It has been observed that the highest reduction rate in thermal resistance is 72% for CuO / water and 77% for CuO + Fe / Water.

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