Performance investigation of double-stage metal hydride based heat pump

Satheesh, A.; Muthukumar, P.

doi:10.1016/j.applthermaleng.2010.07.021

Cited by 29 publications

(7 citation statements)

References 19 publications

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“…The heating/cooling effect thus produced, can be used later in a variety of heat pump applications such as the air conditioning of vehicle interiors at the time of discharging or refueling the tank. [3][4][5][6][7][8][9] This work devises a framework to develop and optimize a hybrid FC propulsion source powered by MHTs for transport applications.…”

Section: Motivation and Challengesmentioning

confidence: 99%

Coupling a metal hydride tank with a PEMFC for vehicular applications: A simulations framework

et al. 2021

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This paper presents a thermal coupling topology of a proton exchange membrane fuel cell (PEMFC) with a metal hydride tank (MHT) based on FeTi metal hydride (MH) for vehicular applications. Usually, the heat produced by the PEMFC is evacuated to the ambient and MHT is heated by an external heat source, which negatively affects the efficiency of the PEMFC system as a whole. The idea is to reuse the heat generated by the PEMFC and re-inject it into the MHT to extract the usable hydrogen (H 2 ) for PEMFC. Initially, a comprehensive model of a multiphysics system to manage the exchange of energy flux among the PEMFC and MHT is developed. Subsequently, two distinctive heat exchangers are integrated into the multiphysics system. The performance of the overall system depends on the effective regulation of both temperature and pressure associated with introduced exchanges. For that, two parallel controllers are devised to simultaneously regulate the H 2 pressure and temperature of the PEMFC stack. The simulations of the system are established on MATLAB/Simulink software. It is shown by the simulation results that the proposed controller achieves the two requested objectives: maintaining the temperature and pressure of both the PEMFC stack and MHT for reliable operation.

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Section: Motivation and Challengesmentioning

confidence: 99%

Coupling a metal hydride tank with a PEMFC for vehicular applications: A simulations framework

et al. 2021

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“…where N is the number of atoms in the cell, k B is Boltzmann's constant, T is the absolute temperature, o L is the maximal frequency and g(o) is the frequency distribution function. Therefore, by adding the electronic contribution, E elec , calculated using DFT as implemented in VASP, the zero-point energy of the quantum harmonic oscillator, ZPE = E(0 K) = 1 2 ho, and the phonon contribution, the total internal energy E(T) = E elec + ZPE + E phonon (T) is obtained. The Helmholtz free energy, F(T), is given by F(T) = E(T) À TS(T) in which S(T) = S phonon (T) is the vibrational entropy at the absolute temperature T. The Helmholtz free energy was considered to be equal to the Gibbs free energy since the PV term (in which P is the pressure and V the volume) can be neglected for solids under the conditions mentioned before.…”

Section: Theoreticalmentioning

confidence: 99%

“…In particular, the need for better vehicular hydrogen storage systems has generated high demands on the energy density of storage media. Metal hydrides have a wide variety of applications outside of stationary and vehicular hydrogen storage, e.g., in metal hydride based refrigerators, 1 pneumatic actuators, 2 heat pumps utilizing metal hydrides as solid state compressors, 3 hydrogen separation from mixed gas streams and isotopic enrichment, 4 and metal hydride batteries 5 to name some. Several comprehensive reviews further enumerate numerous other applications of metal hydrides.…”

Section: Introductionmentioning

confidence: 99%

The catalytic reactions in the Cu–Li–Mg–H high capacity hydrogen storage system

Braga

El–Azab

2014

Phys. Chem. Chem. Phys.

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A family of hydrides, including the high capacity MgH2 and LiH, is reported. The disadvantages these hydrides normally display (high absorption/desorption temperatures and poor kinetics) are mitigated by Cu-hydride catalysis. This paper reports on the synthesis of novel CuLi0.08Mg1.42H4 and CuLi0.08Mg1.92H5 hydrides, which are structurally and thermodynamically characterized for the first time. The CuLi0.08Mg1.42H4 hydride structure in nanotubes is able to hold molecular H2, increasing the gravimetric and volumetric capacity of this compound. The catalytic effect these compounds show on hydride formation and decomposition of CuMg2 and Cu2Mg/MgH2, Li and LiH, Mg and MgH2 is analyzed. The Gibbs energy, decomposition temperature, and gravimetric capacity of the reactions occurring within the Cu-Li-Mg-H system are presented for the first time. First principles and phonon calculations are compared with experiments, including neutron spectroscopy. It is demonstrated that the most advantageous sample contains CuLi0.08Mg1.92 and (Li) ∼ Li2Mg3; it desorbs/absorbs hydrogen according to the reaction, 2CuLi0.08Mg1.42H4 + 2Li + 4MgH2 ↔ 2CuLi0.08Mg1.92 + Li2Mg3 + 8H2 at 114 °C (5.0 wt%) - 1 atm, falling within the proton exchange membrane fuel cell applications window. Finally the reaction 2CuLi0.08Mg1.42H4 + MgH2 ↔ 2CuLi0.08Mg1.92 + 5H2 at 15 °C (4.4 wt%) - 1 atm is found to be the main reaction of the samples containing CuLi0.08Mg1.92 that were analyzed in this study.

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“…Nishizaki et al have reported a model for COP estimation of HSRS by employing LaNi 4.7 Al 0.3 ‐LaNi 5 pair 4 . Muthukumar and co‐workers used metal hydride pairs of MmNi 4.6 Al 0.4 ‐MmNi 4.6 Fe 0.4, 5 LaNi 4.1 Al 0.52 Mn 0.38 ‐LmNi 4.91 Sn 0.15 ‐Ti 0.99 Zr 0.01 V 0.43 Fe 0.09 Cr 0.05 Mn 1.5, 6 La 0.35 Ce 0.45 Ca 0.2 Ni 4.95 Al 0.05 ‐LaNi 5 ‐LaNi 4.35 Al 0.65 , 7 and LaNi 5 ‐LaNi 4.35 Al 0.65 8 for the development of cooling and heating systems. Recently, the thermodynamic simulation and, heat and mass transfer analysis of a metal hydride system is carried out by Man Mohan et al 9 to produce refrigeration as well as heating effects.…”

Section: Introductionmentioning

confidence: 99%

Performance comparison betweenH₂‐metal hydrides andCO₂‐adsorbents‐based sorption refrigeration systems

Syed

Sharma

2020

Int J Energy Res

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In the present study, the performance of H 2-metal hydrides-based (HSRS) and CO 2-adsorbent-based refrigeration systems (CSRS) are investigated and compared. The pair of metal hydrides (MH) used for HSRS is La 0.9 Ce 0.1 Ni 5-LaNi 4.7 Al 0.3 whereas, for CSRS, it is Activated Carbon-Pore Expanded Mesoporous Silica (PEMS) adsorbents. The above pairs are chosen due to their suitability toward the sorption refrigeration system, which results from the screening of different pairs. The performances of these systems are investigated through the thermodynamic simulation as well as computational fluid dynamics (CFD) approach. The thermodynamic cycles of both the systems are analyzed for the operating temperatures of 0 C (T r ; refrigeration), 25 C (T a ; heat sink), and 100 C (T s ; heat source). Upon thermodynamic simulation, the refrigeration output, coefficient of performance (COP), specific refrigeration power, and second law efficiency are observed as 87.04 kJ, 0.91, 24.17 W/kg, and 41.6% for HSRS whereas, it is 49.32 kJ, 0.72, 20.55 W/kg, and 33.1% for CSRS, respectively, using 0.5 kg of each alloy. The CFD simulation results in the behavior of absorbent/adsorbent beds concerning temperature and gas mass variations. The minimum bed temperature is observed to be −31 C in HSRS, which is lower than that of CSRS (i.e.,-9 C). The overall cycle time is predicted to be 3600 seconds for HSRS and 2400 seconds for CSRS. The shorter cycle time in CSRS is due to the high-pressure differential between coupled beds during reactions and higher reaction rates of adsorbent materials than metal hydrides. Though CSRS possessed shorter cycle time, HSRS is found to be more suitable for refrigeration application due to better thermodynamic performance, in the given operating temperature range. Besides, the influence of variations in operating temperatures on the system performance is investigated and obtained the optimum temperature range of T r = 5 C, T a = 20 C, and T s = 95 C. Finally, the thermodynamic performances of HSRS, CSRS, and CO 2-based vapor adsorption refrigeration system (CO 2 VARS) are compared and observed that HSRS possessed better refrigeration performance among three.

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Performance investigation of double-stage metal hydride based heat pump

Cited by 29 publications

References 19 publications

Coupling a metal hydride tank with a PEMFC for vehicular applications: A simulations framework

Coupling a metal hydride tank with a PEMFC for vehicular applications: A simulations framework

The catalytic reactions in the Cu–Li–Mg–H high capacity hydrogen storage system

Performance comparison betweenH₂‐metal hydrides andCO₂‐adsorbents‐based sorption refrigeration systems

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Performance investigation of double-stage metal hydride based heat pump

Cited by 29 publications

References 19 publications

Coupling a metal hydride tank with a PEMFC for vehicular applications: A simulations framework

Coupling a metal hydride tank with a PEMFC for vehicular applications: A simulations framework

The catalytic reactions in the Cu–Li–Mg–H high capacity hydrogen storage system

Performance comparison betweenH2‐metal hydrides andCO2‐adsorbents‐based sorption refrigeration systems

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Performance comparison betweenH₂‐metal hydrides andCO₂‐adsorbents‐based sorption refrigeration systems