Heat transfer in latent heat thermal energy storage unit using paraffin/carbon-fiber composite material

摘要

A new thermal energy storage unit of shell-and-tube type is developed. The feature of this unit is that brushes made of carbon fibers with a high thermal conductivity (190 W/(m·K)) are inserted to enhance the effective thermal conductivity of the energy storage media. The temperatures of the inlet and outlet fluid as well as those of the shell side are measured during energy charge and discharge processes. It is found that the carbon brushes essentially enhance the heat exchange rate between the heat transfer fluid and the energy storage media during both processes. A mathematical model describing the three-dimensional heat transfer in the unit is numerically solved using a finite volume method. Numerical results are consistent with the experimental results when the thermal resistance between tubes and thermal energy storage media is considered.