Exploring the Impact of Microencapsulated Phase Change Materials (PCMs) on Heat Transfer Performance in an Oscillating Heat Pipe

This paper presents a comprehensive experimental study on the influence of Microencapsulated Phase Change Materials (MPCMs) on the heat transfer performance in an oscillating heat pipe (OHP) to improve its heat transfer efficiency. The concept is based on the sensible heat enhancement of MPCMs within the OHP: as the thermally excited oscillations propel MPCMs from the condenser to the evaporator, they undergo a phase change from solid to liquid, effectively absorbing and storing more thermal energy. Subsequently, when these MPCMs reach the condenser section, they change back to a solid state, releasing the stored thermal energy. In the investigation, MPCMs of various diameters (ranging from 10 μm to 27 μm) were prepared and added to water, the working fluid. The study explored the effects of encapsulation ratio, encapsulation efficiency, geometric dimensions, density, and latent heat of MPCMs on the overall thermal performance of the OHP. The experimental findings demonstrated that the incorporation of MPCMs into the working fluid enhanced the OHP's heat transport capability. The optimal performance was observed at an MPCM weight concentration of 3% in the base fluid (water), which resulted in an impressive 15.5% increase in thermal conductance for the OHP. These results highlight the promising potential of MPCMs as effective enhancers for OHPs, paving the way for more efficient and advanced heat transfer systems in various engineering applications.