Hydrogen-Argon Power Cycle (HAPC) on a Wartsila medium-speed engine: an Investigation using 1D-Simulation.

The hydrogen argon power cycle (HAPC) is the next big thing for the energy sector. It offers a groundbreaking approach to achieving zero-emission and high-efficiency power generation by leveraging hydrogen's clean burning properties and argons’ superior thermodynamic characteristics. This study investigates the integration of HAPC into a medium-speed Wärtsilä (W6L20-2STC) engine, utilizing one-dimensional modelling in GT Suite software to analyse and investigate the engine performance across a range of operating conditions. The thesis investigates critical parameters influencing combustion dynamics, efficiency, and emissions in the closed-loop W6L20-2STC engine model. These parameters include variation in Argon to Oxygen ratios (mixture composition), the use of alternative inert gases (e.g., argon, helium) as diluents, compression ratios (CRs), exhaust back pressure, oxygen to fuel ratios, and hydrogen fuel impurities. The study combines a comprehensive literature review on the Argon power cycle (APC) with a detailed W20 engine model simulation. A six-cylinder closed-loop simulation model was developed in GT-Suite for HAPC operations based on a fully functional and rigorously validated W6L20-2STC engine model obtained from Wärtsilä. The turbocharger was removed, and a new condenser was introduced to separate H2O from the HAPC Cycle, for a controlled environment evaluation. The simulations were conducted across various parameter sweeps to systematically examine their impact on HAPC engine and system performance. This thesis provides critical insight into optimizing HAPC-based engine systems to improve its performance and environmental impacts. The integration of a valued simulation model with literature findings offers a robust framework for advancing sustainable engine technology. Results reveal that replacing air with an argon and oxygen mixture in a closed-loop configuration enhances thermal efficiency compared to state-of-the-art marine engines. The simulations depict an optimized efficiency reaching 58.04% while eliminating NOx emissions completely due to the absence of atmospheric nitrogen. The integration of essential components such as water condensers and an ejector, oxidizers, and fuel injectors ensure a closed-loop operation that conserves argon and maintains high system efficiency. These system-level simulation outcomes were critically analysed with the design constraints of the closed-loop HAPC system for the W20 engine while considering real-world implementation scenarios. An optimal argon-to-oxygen mixture composition for the closed-loop HAPC was identified as 90% to 88% argon with 10% to 12% oxygen, achieving an effective balance between power output, efficiency, and engine durability. A compression ratio of 11.90 was found to maximize the engine efficiency while stoichiometric mixtures (λ=1) with an exhaust back pressure after the condenser of 3.23 bar enhanced combustion performance with rather than border-line thermal load levels. Furthermore, impurities in hydrogen, such as dilution with 2% nitrogen, have been shown to significantly reduce in-cylinder pressure and combustion efficiency over time in consecutive simulation cycles, indicating a miserable decline in HAPC efficiency gains over conventional air cycles. This study highlights HAPC as a sustainable energy solution, offering superior efficiency and environmental benefits over conventional air cycles. HAPC has the potential to bridge the gap between renewable energy storage and flexible power generation while supporting global decarbonization and clean energy goals. The findings from this thesis work contribute towards the development of system-level understanding of the HAPC power systems.