Author: Mohiodin Nazemi (University of Iceland) - Seaweed is regarded as an advanced biomass that is valued for its environmental benefits and wide range of applications. However, its high water content requires drying before it can be practically utilized. This study investigates the drying performance of Bladderwrack seaweed through the combined use of unheated (cold) and heated (warm) airflow. In the study, 15 g of Bladderwrack seaweed batches were dried with a constant airflow in a thermal insulated chamber by using a regular electric heater with solid-state relays, controlled by a Raspberry Pi through Python code.
The drying efficiency is compared with cold and warm airflow over a 30-minute period. Warm airflow achieved a higher water content (WC) reduction (45.45%) but required high energy consumption (1718 kJ). In contrast, cold airflow consumed only 38.1 kJ but had a lower WC reduction (17.96%). As the WC is lower(ed), drying seaweed with cold airflow is more feasible when combined with warm airflow. These results indicate that cold airflow is a more economical option during the early stages of drying when the moisture content is high in the seaweed. Based on these findings, the study proposes a dynamic drying strategy that initiates the drying process with cold airflow and gradually incorporates warm airflow as the drying process progresses.