Thermal Management of Electronic Devices Using Combined Effects of Nanoparticle Coating and Graphene–Water Nanofluid in a Miniature Loop Heat Pipe

The thermal management of electronic devices such as high-end central processing units, graphic processing units, insulated gate bipolar transistor, and circuit breaker in low-voltage switchboard operating between 20 and 380 W is investigated using a miniature loop heat pipe (mLHP) having nanoparticle-coated evaporator with graphene-water nanofluid. The thermal evaporation method is used to deposit copper nanoparticles on the evaporator surface for a coating thickness of 400 nm. The experimental results show that the combination of nanoparticle coating and nanofluid gives the highest heat transfer compared to the mLHP having uncoated and coated evaporator with distilled water as a working fluid. The use of nanofluid enhances the heat transfer performance of mLHP with an average reduction of 45.2% in thermal resistance and an average enhancement of 113.4% in evaporator heat transfer coefficient for the optimum nanofluid volume concentration of 0.006%. Similarly, the lowest evaporator temperatures are also obtained with the same concentration of nanofluid for various heat loads. The experimental results of mLHP having nanoparticle coating and nanofluid are also found to be repeatable from the repeated tests and suitable for a long-term operation.