Abstract Heat exchanger design plays a significant role in the performance of solid state hydrogen storage device. In the present study, a cylindrical hydrogen storage device with an embedded annular heat exchanger tube with radial circular copper fins, is considered. A 3-D mathematical model of the storage device is developed to investigate the sorption performance of metal hydride (MH). A prototype of the device is fabricated for 1 kg of MH alloy, LaNi<inf>5</inf>, and tested at constant supply pressure of hydrogen, validating the simulation results. Absorption characteristics of storage device have been examined by varying different operating parameters such as hydrogen supply pressure and cooling fluid temperature and velocity. Absorption process is completed in 18 min when these parameters are 15 bar, 298 K and 1 m/s respectively. A study of geometric parameters of copper fins (such as perforation, number and thickness of fin) has been carried out to investigate their effects on absorption process. © 2015 Hydrogen Energy Publications, LLC.

M. Prakash Maiya

Department of Mechanical Engineering

Anurag Singh

Absorption cooling

Copper

Fins (heat exchange)

Heat exchangers

Hydrides

Hydrogen

MASS TRANSFER

Virtual storage

ABSORPTION CHARACTERISTICS

Heat and mass transfer

HEAT EXCHANGER DESIGN

HYDROGEN STORAGE DEVICE

Metal hydrides

Operating parameters

Solid-state hydrogen storage

SORPTION PERFORMANCE

Hydrogen storage

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IIT Madras

International Journal of Hydrogen Energy

In the present study, a cylindrical solid state hydrogen storage device embedded with finned heat exchanger is numerically investigated. The finned heat exchanger consists of two ‘U’ shaped tube and circular fins brazed on the periphery of the tubes. 1 kg of LaNi5 alloy is filled inside the device and 80 g of copper flakes is evenly distributed in between the fins to increase the overall thermal conductivity of the metal hydride. Water is used as heat transfer fluid. Absorption performance of the storage device is investigated at constant hydrogen supply pressure of 15 bar and cooling fluid temperature and velocity of 298 K and 1 m/s respectively. At these operating conditions, the required charging time is found to be around 610 s for a storage capacity of 12 g (1.2 wt%). The study is extended to examine the influence of different heat exchanger configurations based on number of fins, thickness of the fins, diameter of tubes, holes in fins, amount of copper flakes etc. An analysis for the same weight of the heat exchanger assembly has also been carried out by changing the number of fins at different thickness and pitch. © 2017 Hydrogen Energy Publications LLC

Performance of a solid state hydrogen storage device with finned tube heat exchanger

The absorption and desorption performances of a solid state (metal hydride) hydrogen storage device with a finned tube heat exchanger are experimentally investigated. The heat exchanger design consists of two “U” shaped cooling tubes and perforated annular copper fins. Copper flakes are also inserted in between the fins to increase the overall effective thermal conductivity of the metal hydride bed. Experiments are performed on the storage device containing 1 kg of hydriding alloy LaNi5, at various hydrogen supply pressures. Water is used as the heat transfer fluid. The performance of the storage device is investigated for different operating parameters such as hydrogen supply pressure, cooling fluid temperature and heating fluid temperature. The shortest charging time found is 490 s for the absorption capacity of 1.2 wt% at a supply pressure of 15 bar and cooling fluid temperature and velocity of 288 K and 1 m/s respectively. The effect of copper flakes on absorption performance is also investigated and compared with a similar storage device without copper flakes. © 2017 Hydrogen Energy Publications LLC

Experiments on solid state hydrogen storage device with a finned tube heat exchanger

Effects of heat exchanger design on the performance of a solid state hydrogen storage device

Journal	Data powered by TypesetInternational Journal of Hydrogen Energy
Publisher	Data powered by TypesetElsevier Ltd
ISSN	03603199
Open Access	No