An analysis of a metal hydride-based system for simultaneous heat transformation and refrigeration is presented. A six-reactor configuration comprising of three different hydriding alloys has been considered taking account of the coupled heat and mass transfer in the reactors. The influence of parameters like cycle time and operating temperatures has been studied. It was found that the cycle time plays an important role and has to be selected judiciously for specified output. Among the various operating temperatures it was observed that the heat source and heat rejection temperatures have significant influence on the system performance. © The Author 2009. Published by Oxford University Press. All rights reserved.

M. Prakash Maiya

Department of Mechanical Engineering

CYCLE TIME

Heat and mass transfer

HEAT TRANSFORMATIONS

Metal hydride

SIX REACTOR CONFIGURATION

Heat transfer

Hydrides

MASS TRANSFER

Metals

Refrigeration

Temperature

Coupled circuits

Fulltext

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IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

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IIT Madras

International Journal of Low-Carbon Technologies

Out of the many promising applications of metal hydrides, refrigeration, heat pumping and heat transformation are important. In order to achieve improved performance, a novel three-alloy cycle is proposed in which, for heat input at an intermediate temperature, heat outputs at high temperature and also at warm temperature are obtained in addition to refrigeration. The performance of this cycle using the alloys LaNi4.6Sn0.4, LaNi4.7Al0.3 and MmNi4.5Al0.5 is studied based on thermodynamics and reaction kinetics. Coefficients of performance, half-cycle times and specific alloy outputs are evaluated. © 2003 Elsevier Ltd. All rights reserved.

Renewable Energy

Analysis of a novel metal hydride cycle for simultaneous heating and cooling

International Journal of Hydrogen Energy

Heat transfer characteristics of expanded graphite matrices in metal hydride beds

Simulation of hydride heat pump operation

Thermal modelling and analysis of a metal hydride chiller for air conditioning

The performance of a metal-hydride refrigerator working with a ZrMnFe MmNi4.5Al0.5 pair is predicted by solving the coupled heat- and mass-transfer equations of the two reactors. Effects of bed parameters such as bed thickness and effective thermal conductivity, and operating parameters such as heat-source temperature and refrigeration temperature are studied. Results show that the specific output, and hence the cost of the system, depend significantly on these parameters. Of the four processes which constitute the cycle, desorption at the low-temperature reactor is the slowest. For a given bed thickness, there is an optimum effective thermal conductivity above which its effect on cycle time and specific output is negligible. This optimum value increases with increasing bed thickness, thereby emphasizing the advantages of thin beds. © 1995.

Prediction of metal-hydride refrigerator performance based on reactor heat and mass transfer

Performance of a metal hydride device for simultaneous heat transformation and refrigeration

Journal	International Journal of Low-Carbon Technologies
ISSN	17481317
Open Access	Yes