Experimental investigation of the effect of the use of graphen oxide as nano fluid on thermal performance in heat exchangers

In this study, it has been tried to increase the thermal efficiency by using nanofluid in plate type heat exchangers. In the experiments, a combined hot water preparation system with a plate heat exchanger was used as the experiment set. The aim of the study is to experimentally investigate the effect of using graphene oxide-water nanofluid as hot fluid on thermal efficiency compared to pure water in plate type heat exchangers. The average particle size of the graphene oxide particles used in the experiments is 7.5 nm and the purity is 99.8%. The experiments were carried out under counter flow conditions, and in the experiments, nanofluids formed by adding graphene oxide particles in volumetric ratios of 0.02% to 0.04%to pure water were used. In the study, five different values were chosen so that the cold water flows would be 4,5,6,7,8 l/min. The inlet temperatures of the hot fluid to the plate heat exchanger are taken as 40, 45, 50, 55, 60 ˚C. In all experiments, the amount of heat transfer, efficiency coefficient and improvement rate were analyzed. The highest improvement rate value was reached in experiments with 0.04% graphene oxide-water nanofluid. When the results obtained were examined, the highest improvement rate of 0.04% by volume of nanofluid was obtained as 8.8%at 4 l/min. The efficiency coefficient increased in direct proportion to the increase in the hot fluid inlet temperature. As the flow rate increases, the efficiency coefficient decreases. It has been observed that the use of nanofluid significantly increases the heat transfer compared to pure water.