Experimental investigation of flow and thermal behavior in channels with PCM-filled thermal energy storage columns for potential application in photobioreactors
Abstract
Microalgae has been identified as a potential source for the production of biofuels and other bio-products. The growth of microalgae is sensitive to the temperature variations inside the photobioreactor. The present research investigated an innovative approach to thermally regulate photobioreactors by introducing passive thermal energy storage using phase change material (PCM). The research was specifically focused on a novel design to integrate thermal storage in the reactor channel in the form of offset columns containing PCM. Two column shapes were considered: circular and square. The first part of the study was focused on characterizing the influence of offset column shapes on flow dynamics in the channel over a range of Reynolds numbers 20-90. Experiments with microalgae Chlamydomonas reinhardtii were also conducted in a similar setup to determine if the presence of obstacles would impact the algae growth. The second part of the study was focused on the thermo-fluid characterization in a similar configuration using PCM-filled offset columns. Experiments were conducted over a Reynolds number range 40 to 120 at three inlet fluid temperatures 28 °C, 33 °C and 38 °C. The results show that the modification of the flow field in the channel due to the column shapes influenced the heat transfer into the PCM thermal storage.