During the doctoral promotion session held on January 9, 2023, Wisnu Indrawan presented an innovative solution aimed at improving the efficiency of dehumidification in air conditioning systems. A doctoral student from the Mechanical Engineering program at FTUI, Wisnu conducted research in response to concerns about the spread of SARS viruses through building air conditioning systems. To address this issue, Wisnu developed a more effective air drying system, considering the balance between energy requirements and good air quality.
Wisnu’s innovation involves the use of liquid desiccant based on ionic solution as an alternative to conventional air dehumidification technology. This research explores optimal dehumidification and regeneration systems through a series of experiments, including a heat exchanger consisting of cooling and heating coils.
“To achieve optimal values, these experiments involved setting the cold water temperature at 10 °C during dehumidification and hot water at 36 °C during regeneration. The results showed an increase in solution temperature and air output, along with a decrease in relative humidity. Additionally, the correlation between the air mass flow rate and humidity ratio provides insights into mass transfer performance during the dehumidification process,” said Wisnu.
The research results indicate that increasing the solution flow rate during the dehumidification process produces a significant difference in humidity ratio between the incoming and outgoing air. Similarly, during regeneration, an increase in the solution flow rate reduces the humidity ratio between incoming and outgoing air. Furthermore, the findings suggest that lower ionic liquid temperatures result in a larger humidity ratio.
A reduction in water content in the incoming air channel also contributes to reducing the humidity ratio. In developing the prototype of the liquid desiccant dehumidifier with ionic liquid, Wisnu used two tube columns, five rows of tubes, a fin length of 2 x 10 m, a fin pitch of 2 x 10, an outer tube diameter of 1.4 x 102 m, the tube wall thickness of 1.3 x 10 m, horizontal tube pitch of 3 x 102 m, and vertical tube pitch of 3 x 10 m. This apparatus has a total frame length of meters with a tool width of 50 cm.
“The best liquid desiccant distributor geometry is using a pattern distributor 2 and a diameter of 1.0 mm because it has a wetting ratio of 71 sides of the fin out of 80 fin sides available, with a wetting ratio of 22.5%. The results show an increase in dehumidification and enthalpy effectiveness with the increasing wetting ratio value during the regeneration process,” explained Wisnu.
FTUI Dean, Prof. Dr. Heri Hermansyah, ST., M.Eng., IPU, gave a response regarding this research, “This research not only provides a deep understanding of the use of liquid desiccant in dehumidifier systems but also offers sustainable solutions to improve air quality in various indoor spaces. Through this research, Wisnu Indrawan has proven that his innovation can provide an efficient solution to enhance indoor air quality and is expected to serve as a foundation for the development of more sustainable technologies in the future.”
Thanks to his research, Wisnu Indrawan successfully earned a doctoral degree with a GPA of 3.93 and the predicate Cum Laude in this doctoral promotion session. Wisnu is the 102nd doctoral graduate from the Department of Mechanical Engineering and the 528th doctoral graduate from FTUI. Additionally, he is also one of the recipients of the Master’s Education toward Doctorate for Superior Bachelor’s (PMDSU) scholarship.
The Doctoral Promotion Session was led by the Chair of the Session, Prof. Dr. Ir. Yanuar, M.Eng., M.Sc., with the Supervisor, Prof. Dr. Ir. M. Idrus Alhamid, and Co-Supervisor, Dr. Eng. Arnas, S.T., M.T. The Examination Committee consisted of Assoc. Prof. Ts.dr. Haslinda Binti Mohamed Kamar, Prof. Dr.-Ing. Ir. Nasruddin, M.Eng, Dr. Ir. Budihardjo, Dipl. Ing, Ardiyansyah, S.T., M.Eng., Ph.D, and Dr. Eng. Muhammad Arif Budiyanto, S.T., M.T.
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