Two-Temperature Integral Analysis of a Compressor-Driven Metal Hydride Heat Pump

Abstract

An integral method is used to analyze the performance of a complete system model of a compressor-driven metal hydride heat pump. CFD studies incorporating the transient non-isothermal fully compressible nature of such systems have confirmed that high specific powers and COPs comparable to vapour compression cycles are achievable. Finite-time thermodynamic studies focusing on specific aspects of external heat exchanger design have identified the need for less computationally intensive models which include in a detailed manner all parasitic thermal losses as well the capability of capturing the thermal phase lags which occur between the reactors and the heat exchangers during steady-state operation. This paper develops a rigorous intermediate model which captures these effects. Parametric studies are presented as well as comparision with data from a prototype device.

Performance study of a hydrogen powered metal hydride actuator

“…The input to the actuator can be quantified by identifying the two parameters namely, heat of reaction (Q r ) and heat lost (Q loss ) to the ambient. The heat of the reaction can be quantified by calculating the amount of hydrogen desorbed in moles, using gas law, and multiplying that by the reaction enthalpy (ΔH=−1.539×10 7 J kg −1 H 2 [24]) as shown in equation (5). Where, P, V, Z (1.008), R and T are pressure, volume, compressibility factor, gas constant and temperature respectively; subscript 0 and 1 represents the initial and final states of the process…”