Numerical Simulations on the Thermal Performance of a Metal Hydride Based Heat Pump

Abstract

Over the decade, the energy utilised for heating, ventilation, refrigeration, and air-conditioning extended about 24% of the total energy consumption. Due to this amplified energy consumption and need for immense clean energy, metal hydride based heating and cooling systems utilising low-grade heat recovery and eco-friendly working fluid have attracted more lavish attention by researchers globally. In this manuscript, such a system comprising LaNi4.3Mn0.7 (high-temperature bed) and LaNi5 (lowtemperature bed) metal hydride pair considered as the working pair for a heat pump system. The single stage-metal hydride heat pump encapsulates spiral heat exchanger configuration in a standard AISI 316L 2” diameter seamless welded reactor filled with 0.7 kg alloy of LaNi4.3Mn0.7 and LaNi5. The heat transformer's dynamic thermal performance is evaluated using a numerically designed unsteady 3-D finite element method in COMSOL Multiphysics 5.6 by solving the coupled heat and mass transfer equations across the reactors. Performance evaluation parameters, namely coefficient of performance of the system (COP) and specific heating power (SHP) of the heat pump, are calculated as 0.365 and 210.54 W/kghydride, respectively. The maximum temperature lift and thermal efficiency of the heat pump are evaluated as 46.27 K and 0.53 for the given operating range of 180/120/30°C (TH/TM/TC). The numerically estimated outcomes matched the data published in the literature with a reasonable level of accuracy