Publications Repository - Gdańsk University of Technology

This paper deals with thermal energy storage with use of nanoparticle enhanced phase change material in shell-and-multitube unit. The experiments are conducted under atmospheric pressure. Paraffin wax and two different fatty acids are used as base phase change material. Graphite and multi-walled carbon nanotubes serve as nanoparticles. Graphite nanoparticles are tested at the concentrations of 0.1%, 1% and 5% by weight, while multi-walled carbon nanotubes only at 0.1%wt. Ultrasonic vibration and homogenizer are used in order to stabilize the dispersion of the nanoparticles. Polyvinylpyrrolidone surfactant is used to stabilize the suspension and the tested nano-enhanced phase change material exhibit satisfactory stability. Experimental measurements are performed for a bundle of 7 tubes with outside diameter of 6 mm in a staggered arrangement and a pitch ratio of 4.5. It is found that, regardless of the tested base phase change material, the addition of graphite nanoparticles with mass concentration of 0.1% does not significantly affect the charging and discharging times compared to base phase change material. The differences in charging and discharging times did not exceed 11%. For a graphite nanoparticles mass concentration of 5%, an increase in the charging time by up to 21% and a reduction in the discharging time by 24% was observed, depending on the type of base phase change material. An addition of multi-walled carbon nanotubes with mass concentration of 0.1% shows an increase in charging time regardless of the type base phase change material up to 144% with negligible influence on the discharging time. It was also observed that adding a surfactant to the produced nano-enhanced phase change material results in a reduction in charging time by up to 83% depending on the type of base phase change material.

Authors

• Maciej Fabrykiewicz,
• prof. dr hab. inż. Janusz Cieśliński link open in new tab