Experimental analysis of a paraffin-based cold storage tank

•Analysis of an experimental cold storage tank containing paraffin.•Temperature measurements of the phase-change material and heat transfer fluid.•Thermal power, storage capacity and overall efficiency are discussed.•Up to 31% of dead volume in the center and base of the tank.•The highest efficiency is reached for low supply temperatures and mass flow rates.

The aim of this study is to characterize a paraffin-based cold storage tank. Novel experimental results are presented for this system which combines a significant amount of paraffin (1450 kg) immersed around 18 spiral-shaped coils disposed in counter-current flow. The paraffin has a phase-change temperature in the range 4–8 °C as measured by a 3-layer calorimeter. Different tests have been carried out with a constant mass flow rate and supply temperature. Around 31% of the paraffin has hardly any contact with the coils and hereby acts as a dead mass. The results show the importance of natural convection within the phase-change-material, particularly during the melting process. The highest efficiency has been achieved for the lowest supply temperatures and mass flow rates of the heat transfer fluid.