Abstract

• Problem Statement: The transportation industry's push for efficient energy use and stricter emission regulations drives research into ORC-based EHR systems. Considering integrating these systems into vehicles, it's essential to study their operating conditions, energy, economic performance, and potential CO₂ savings. This research will help determine the feasibility of using EHR systems in long-haul trucks and guide future design and financial evaluations.
• Purpose of the Study: Exhaust heat recovery (EHR) has recently been considered a viable means of achieving sustainable use of fossil fuel resources in the transportation sector, meeting future CO₂ legislation, and improving thermal efficiency - the primary technological driver in internal combustion engine (ICE) research. The transportation industry accounts for a substantial share of global oil consumption, amounting to 64%, which translates to 16.2% of worldwide greenhouse gas (GHG) emissions. Among these emissions, on-road vehicles contribute 11.9%, with trucks alone responsible for 22% of the sector's total emissions. Unlike in developed nations, where dedicated environmental oversight entities monitor emissions from critical sectors, regions such as Nigeria and other developing countries lack adequate GHG monitoring systems, despite the profound impact of emissions on air quality and public health. Therefore, harnessing the exergy in these exhaust gases not only aids in emission reduction efforts but also enhances the efficiency of ICE technology. The study's objectives encompassed modeling the system coupled to a commercial truck engine, assessing its thermal efficiency, and quantifying its potential for emissions reduction.
• Methods: The investigation utilized two research methodologies: designing and simulating the ORC-based WHR system using GT-Suite software, and assessing its potential emissions reduction..
• Results: Employing R245fa as the working fluid and simulated in GT-Suite, the proposed model yielded notable results: a power output of 3.48 kW, thermal efficiency of 6.39%, and a 3.27% enhancement in specific fuel consumption (SFC) at a maximum truck speed of 119 km/h. Additionally, it achieved an annual reduction of up to 4,767 kgCO₂ emissions, marking a 4% decrease in typical commercial truck engine emissions. This research underscores the potential of integrating the proposed EHR system into automobiles to enhance ICE thermal efficiency while combating the global menace of greenhouse gas emissions from exhausts. Moreover, as a developing nation, Nigeria grapples with the adverse effects of global warming; including localized flooding and heightened temperatures due to increased fossil fuel combustion emissions. Hence, concerted efforts toward mitigation are imperative.
• Conclusion/Recommendation: The steady-state model research suggests that adding the proposed EHR system to trucks could greatly enhance engine thermal efficiency and cut greenhouse gas emissions. It also recommends creating a transient module with speed mode to assess the Organic Rankine Cycle (ORC) module, aiming to recover both coolant and exhaust heat while keeping the system design simple for better thermal performance.