Thermal performance of a novel heat transfer fluid containing multiwalled carbon nanotubes and microencapsulated phase change materials

Three new heat transfer fluids consisting of combinations of multi-walled carbon nanotubes (MWCNT) and microencapsulated phase change materials (MPCMs) were formulated, and tested in a turbulent flow heat transfer loop. Stable nanofluids have been prepared using different sizes of multi-walled carbon nanotubes and their thermal properties like thermal conductivity, viscosity and heat transfer coefficient have been measured. Microencapsulated phase change material slurries containing octadecane as phase change material have been tested to determine their durability and viscosity. A blend of MPCM slurry with MWCNT nanofluid has also been prepared to form a new heat transfer fluid that exhibits unique thermophysical properties including non-Newtonian viscous behavior. Heat transfer experiments have also been conducted to determine heat transfer coefficient and pressure drop values of the MWCNT nanofluids, MPCM slurries, and blends of MWCNT with MPCM under turbulent flow and constant heat flux conditions.