Dwika Budianto, a doctoral student in the Mechanical Engineering Program at the Faculty of Engineering, Universitas Indonesia (FTUI), officially earned his Doctoral degree after successfully defending his dissertation in an open session held on Friday (June 13). In his dissertation, Dwika presented his research titled “Utilization of Low-Temperature Waste Heat Using Dual Organic Rankine Cycle (ORC) with R134a and R245fa Working Fluids.”
This research stems from the fact that a significant portion of energy from engines or power plants is lost as heat. If this waste heat can be recovered, overall energy efficiency can be improved. “One of the technologies used for this purpose is the Organic Rankine Cycle (ORC), a system capable of converting heat into electricity. However, at low temperatures, the performance of this system remains suboptimal. To address this, I developed a dual-cycle ORC system to capture and convert more waste heat into electrical energy,” explained Dwika during his presentation.
The system tested by Dwika is a small-scale prototype with a 2 kW capacity, utilizing two types of working fluids: R245fa for high-temperature and R134a for low-temperature applications. The test results showed that the system achieved a thermal efficiency of 10.74% and an exergy efficiency of 12.72% at a heat source temperature of 90 °C. In other words, the system is capable of effectively converting waste heat into electricity on a small scale.
Beyond the technical aspects, the research also explored the economic feasibility of the system. The construction cost is estimated at USD 36,652, with a levelized cost of energy (LCOE) of USD 0.31 per kWh. The system is expected to achieve a payback period of 9.3 years, making it a viable solution for industries that produce waste heat.
The Dean of FTUI, Prof. Dr. Ir. Kemas Ridwan Kurniawan, M.Sc., Ph.D., emphasized that this research represents a concrete contribution from academia in supporting energy efficiency. “This research is a great example of how technology can be utilized to address the energy challenges we face, especially in utilizing waste heat, which often goes untapped,” stated Prof. Kemas.
Dwika Budianto was officially conferred the title of Doctor in Mechanical Engineering from FTUI. Graduating with cum laude honours and a GPA of 3.90, Dr. Dwika becomes the 118th Doctoral graduate from the Department of Mechanical Engineering and the 598th Doctor conferred by the Faculty of Engineering, Universitas Indonesia. The doctoral defence session was chaired by Prof. Dr. Ir. Yanuar, M.Eng., M.Sc., with a supervisory team comprising Prof. Dr. Ir. Imansyah Ibnu Hakim, M.Eng. (Promoter), Prof. Dr. Ir. Muhammad Idrus Alhamid (Co-promoter 1), and Dr. Ir. Cahyadi, M.Kom (Co-promoter 2). The examination committee included: Prof. Dr. Ing. Ir. Nasruddin, M.Eng., Assoc. Prof. Dr. Eng. Muhammad Aziz, Dr. Eng. Arnas, S.T., M.T., and Dr. Tata Sutardi, S.T., M.T., Ph.D.
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