The Department of Mechanical Engineering, Faculty of Engineering, Universitas Indonesia (FTUI), has produced another doctoral graduate through a doctoral promotion defense held on Tuesday (August 6, 2025). Indra Buana successfully defended his dissertation titled “Enhancing the Evaporation Rate of a Horizontal Vacuum Freeze Dryer by Optimizing Airflow and Air Injection.” His research presents an effective method to improve the evaporation rate in a vacuum freeze dryer system configured with a drying chamber aligned parallel to the cold trap.
In his dissertation, Indra addressed the issue of low evaporation rates commonly found in vacuum freeze-drying systems. This problem often results in prolonged drying time, increased energy consumption, and reduced operational efficiency. To overcome these challenges, Indra proposed two innovative approaches: installing a fan between the drying chamber and the cold trap, and introducing controlled air injection into the drying chamber.
“The research findings show that the fan plays a major role in accelerating vapor flow from the drying chamber to the cold trap, significantly increasing the evaporation rate. Meanwhile, air injection also enhances evaporation, although to a lesser extent compared to the fan. This is likely due to the injected air not being completely dry, thereby adding load to the cold trap,” explained Indra.
Furthermore, Indra emphasized that his research not only contributes to improving the performance of vacuum freeze-drying systems but also offers practical implications for various industries.
“With higher energy efficiency, the drying process can be completed faster and more economically, which could potentially reduce production costs in the pharmaceutical, food, and biotechnology industries,” he stated.
Through his study, Indra demonstrated that optimizing vapor flow using a fan and controlled air injection can enhance the energy efficiency of horizontal vacuum freeze dryers. Certain configurations even yielded the best results by shortening the drying time while reducing energy consumption.
For his academic achievement, Indra Buana graduated with the distinction of Very Satisfactory and a Cumulative Grade Point Average (CGPA) of 3.92. He is officially recognized as the 125th Doctor from the Department of Mechanical Engineering and the 622nd Doctor from the Faculty of Engineering, Universitas Indonesia.
FTUI Dean Prof. Kemas Ridwan Kurniawan, S.T., M.Sc., Ph.D., expressed his appreciation for Indra’s accomplishment “This research is highly relevant to today’s industrial challenges, particularly in energy efficiency and sustainability. FTUI is proud to produce outstanding doctoral graduates who not only contribute academically but also provide real solutions to societal and industrial needs,” said Prof. Kemas.
The open doctoral defense was chaired by Prof. Dr. Ir. Harinaldi, M.Eng. as Head of the Committee. The promoter was Prof. Dr. Ir. Engkos Achmad Kosasih, M.T., with Ir. Ardiyansyah, S.T., M.Eng., Ph.D. as co-promoter. The examination committee included Prof. Dr. Ir. Deendarlianto, S.T., M.Eng.; Prof. Dr. Ir. Ahmad Indra Siswantara; Prof. Dr. Ir. Muhammad Idrus Alhamid; Prof. Dr.-Ing. Ir. Nandy Setiadi Djaya Putra; and Dr.-Ing. Ridho Irwansyah, S.T., M.T.
This achievement further strengthens FTUI’s academic reputation in producing distinguished doctoral graduates who contribute meaningfully to the advancement of science and technology in Indonesia.
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Public Communication Office
Faculty of Engineering, Universitas Indonesia
