Design of Passive Internal Heat Transfer Intensifier for Metalhydride Vessels for Mobile Applications
Abstract
For the development of modern transport systems that meet the demanding goals of reducing greenhouse gas emissions, set in the Paris Agreement from the end of 2015, it is necessary to consider new technologies and new vehicle concepts. In addition to the contractually agreed and accelerating need to contribute to significant emissions reductions, such developments would help to replace fossil fuel energy that most countries around the world are heavily dependent from. Thus, fossil fuels cannot be part of a suitable transport system.
The aim of this work is to design an effective passive cooling system for metal hydride pressure vessel which is used for mobile applications.
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Introduction
A promising technological concept that meets the above requirements is the use of hydrogen in combination with fuel cells and an electric engine. Compared to battery electric vehicles, such an approach has the advantage that hydrogen cars could be driven for much longer distances without refuelling. But such a hydrogen-based mobility concept will be successfully implemented in the existing mass market only if hydrogen can be stored safely, quickly and in a technically advanced, economically efficient, and ecological way.
The biggest advantage of using hydrogen in mobile applications is the zero production of emissions (NOx, CO2) when it is burned in fuel cells. An important aspect of the applicability of hydrogen in mobile applications is its energy content. A kilogram of hydrogen has three times higher energy content compared to commonly used fuels such as gasoline (H2: 39.4 kWh·kg-1, gasoline: 12.9 kWh·kg-1 , CNG: 15 kWh·kg-1 and LPG: 14 kWh·kg-1 ). In a volume comparison, the energy content of hydrogen is significantly lower than that of commonly used fuels (H2: 1.6 kWh·l-1 , gasoline: 9.5 kWh·l-1 , CNG: 2.5 kWh·l1 and LPG: 7.3 kWh·l-1 )
Conclusion
The goal of the simulation in the ANSYS CFX program was to design an internal heat transfer intensifier that will effectively remove heat from the core of the metal hydride storage vessel to the outer shell, where the storage vessel is cooled by a cooling liquid. The simulation results showed that the designed intensifier achieves optimal values in all areas of investigation.