Design of a Heat Exchanger for A Tubular Metal Hydride Storage Tank using Air as A Cooling Medium
Abstract
The article in question deals with the issue of cooling the designed tubular metal hydride storage tank with the use of active and passive cooling modules, which are implemented in the designed storage tank. The passive module used in the tank is realized by means of an aluminium heat transfer intensifier, which is placed directly in the metal hydride alloy of the tank, and as an active cooling module, air at a temperature of 10 °C is considered, and in the second simulation, an air temperature of 30 °C is considered.
Keywords
Download Options
Introduction
Sustainable energy conditions all aspects of the functioning of modern society. A fully integrated and well-functioning internal energy market is an essential part of a sustainable national economy, the gradual transformation of which into a system characterized by a significant degree of carbon neutrality is currently highly relevant. Achieving a balance between carbon emissions and their absorption by natural systems requires a significant shift away from the use of fossil energy sources, a rapid increase in the share of renewable energy in total energy consumption, the continuous development of ecological technologies with a view to increasing their efficiency, and the use of climate-neutral energy carriers such as hydrogen.
For hydrogen to become a real alternative to fossil fuels in the long term, it is necessary to look not only for ecological nonfossil sources for its production, but also for efficient systems enabling its long-term and safe storage. Hydrogen storage is a very important component of the hydrogen economy system [1]. Currently, there are many ways to store hydrogen in the world, but the most common storage methods are through compressed gas or high-pressure storage, liquid storage of hydrogen through cryogenic temperatures or based on absorption into a metal alloy or low-pressure hydrogen storage. Hydrogen in the absorption method of storage forms metal hydrides with metals and alloys, which in some cases have a higher storage density than storage in pressure and cryogenic vessels. Storage in metal hydrides is a safer and volume-efficient form of storage. A metal hydride is formed by a host metal lattice and hydrogen atoms. However, this type of storage has its disadvantages, the biggest disadvantage being its weight within the system and at the same time the need to remove the generated heat during the exothermic reaction of hydrogen and metal hydride.
The article in question deals with the design of a heat transfer intensifier for efficient removal of the generated heat from the core of the tubular tank and subsequent cooling of the tank by means of a cooling medium located in the space between the primary tank in which the metal hydride is stored and the outer shell.
Conclusion
The subject of this article was the creation of an efficient cooling system using the active cooling medium of air through external fins that were placed on the outer wall of the tank. The maximum temperatures during the process of absorption into the structure of the metal alloy at an air temperature of 10 °C created temperature fields of the metal hydride alloy at the level of 60 °C, and at an air temperature of 30 °C the temperature fields were at the level of 78 °C, which represents the limit temperature for the absorption of hydrogen into structure of the selected metal hydride alloy and thus it can be concluded that it meets the operating parameters. Based on the simulation, it is also possible to conclude that for the cooling of the tank system designed according to the STN EN 13322-2 standard, the use of external fins for cooling the system is completely sufficient, which reduces production costs.