A series of comparative experiments was conducted to investigate the laminar flow heat transfer characteristics with microencapsulated phase change material(MEPCM) suspensions in water flowing through rectangular mini-channels with a hydraulic diameter of 2.71 mm.MEPCM particles with an average size of 4.97 μm were used to form suspensions with mass concentrations ranging from 0% to 20%.The comparative experiments were done under the same mass flow rates and the same thermal conditions using water and water-based MEPCM suspensions.The cooling characteristics of MEPCM suspension strongly depend on the mass flow rate and the MEPCM mass concentration.The 5% suspension always shows better cooling performance than water with lower wall temperatures and enhanced heat transfer coefficient within the whole range of mass flow rates.At higher mass concentrations

however

the cooling performance is more effective only at low mass flow rates.At relatively higher mass flow rates

it shows less effective cooling performance than water at higher wall temperatures and lower Nusselt numbers.