Effect of airflow channel arrangement on the discharge of a composite metal foam-phase change material heat exchanger

The effect of various arrangements of airflow channel in a proposed storage heater based on copper foam soaked in a phase change material (PCM) is investigated. Different configurations of the air channel using a serpentine channel, as well as numbers of the air channels, are examined in a representative three-dimensional computer-based model (Ansys Fluent). Evaluation is performed by PCM discharging rate and output air temperature of the unit. The goal is to improve both uniformity and value of air temperature. Changing the airflow arrangement using serpentine configuration to increase heat exchange surface area reduces solidification time and increases output maximum air temperature as well as pressure drop; conversely, exit air achieves lower temperature uniformity. In the case of the shortest solidification time using one air-channel with the length of 51 cm, the solidification time reduces to almost 6 hours, compared with 13.6 hours for the straight channel with 37 cm length, with the average output temperature of 56 degrees C compared to 41 degrees C for the straight channel; however, the achieved temperature difference from the initial to the end of solidification time is 13.7 degrees C compared to 4.5 degrees C for the straight tube.

Automated summary

The study investigated the effect of different airflow channel arrangements in a storage heater based on copper foam and phase change material, using a representative three-dimensional computer model for evaluation. Increasing the heat exchange surface area by changing the airflow arrangement helped reduce solidification time and improve maximum output air temperature, but led to lower temperature uniformity of the exit air.