Optimizing the thermal performance of the thermosyphon heat pipe for energy saving with graphene oxide nanofluid

Abstract

A thermosyphon heat pipe (THP) involves a vacuum tube with a specific quantity of liquid. Due to its simplicity of design and structure, THP has many applications in heat recovery and renewable energy devices. Prior studies showed that using stable nanofluids can improve THPs' energy efficiency. In this evaluation, the effect of working fluid type, input heat, two types of surfactants, and nanoparticle concentration on the energy efficiency and thermal resistance of a THP was investigated and optimized. A magnetic stirrer and ultrasonic waves were used to create stability. Imaging and spectrophotometric analysis showed that graphene oxide (GO) nanofluid with SDS surfactant is more stable. The most notable decrease in thermal resistance at an input power of 100 W with GO nanofluids compared to distilled water at an F.R. of 50% was 12%. The highest decrease in the evaporator temperature section was achieved with GO and SDS surfactant at a weight ratio of 0.3% wt, equal to 12.3 °C. This was also confirmed by measuring the contact angle. The highest percentage increase in thermal efficiency of THP with the mixture of GO nanoparticles and SDS surfactant in distilled water with 0.3 wt percent and input heat of 200 W was 18% compared to distilled water. In the optimum condition, the highest percentage increase in thermal efficiency of THP with the mixture of GO nanoparticles and SDS surfactant in distilled water with 0.3 wt percent and input heat of 200 W was 18% compared to distilled water.