Reproducibility of solidification and melting processes in a latent heat thermal storage tank

• Experimental performance tests on a cold storage tank.
• Paraffin with a phase-change temperature in the range 3–8 °C.
• Analysis of the performance reproducibility depending on the tank preparation.
• Only 2% difference in capacity for identical preparation and operation conditions.
• Up to 33% different capacities depending on the supply temperature of the preparation.

This study analyzes the reproducibility of solidification and melting tests in a tank containing 181 kg of paraffin for cold storage at around 8 °C. Firstly, an experimental campaign of 10 identical tests was carried out. The performance is practically the same in terms of PCM temperatures and thermal power, with a maximum deviation of 2% in the capacity of all tests. In a second campaign, the impact of the initial conditions was studied. The results indicate that fixing a same mean PCM temperature at the beginning of the tests is insufficient to ensure an accurate reproducibility. Depending on the heat transfer rate during the preparation tests, the capacity differed in up to 33%. In tanks with such quantities of PCM, fixing a uniform initial PCM temperature is hardly possible, thus it is important to prepare the tank with same operation conditions.