Compressor-driven metal-hydride heat pumps

Compressor driven metal hydride cooling systems—mathematical model and operating characteristics

“…In addition, it is also shown by the authors that the problem of compressor overloading during start-up and during sudden load changes are less severe in compressor driven metal hydride systems compared to the conventional VCRS [8]. Initial thermodynamic studies show that the compressor-driven metal hydride heat pumps (CDMHHPs) have the potential to yield COPs comparable to or even better than that of VCRS [9]. Simple transient computational models developed also indicated the same [10].…”

On the degradation mechanisms of Mg hydride pellets for hydrogen storage in tanks

“…This effect is particularly important in Mg which, having a relatively low melting temperature, displays a noticeable atomic mobility at the expected operating temperature. Powder particle coarsening generally reduces hydrogen permeability in the hydride bed, increases the hydraulic losses and reduces thermal conductivity with a detrimental effect on the device performances [7]. In other words, during operation, an increasing part of the active material is not anymore reacting with hydrogen because of the lack of heat or mass supply.…”

Conceptual design analysis of a compressor-driven sorption cooling system

“…In recent times, refrigeration and air conditioning systems based on metal hydrides have attracted considerable attention [13][14][15][16][17]19,20]. Metal hydride heating and cooling systems are based on the solid-gas reactions between a pair of alloy and hydrogen gas.…”

“…Metal hydride heating and cooling systems are based on the solid-gas reactions between a pair of alloy and hydrogen gas. The CDSR using metal hydride has been studied experimentally [13,21,22] as well as theoretically by many researchers [12][13][14][15][16][17]19,20]. The performance of these systems has been found to be satisfactory.…”

“…The main reasons for this are the high initial cost of the alloys, poor heat and mass transfer of the hydride reactors [23][24][25][26][27] leading to high alloy inventory [28]. Moreover, gradual transformation of metal hydride from granules to powder form causes substantial deterioration in heat transfer [13].…”