PH-97-01-3 -- Cooling Power/Efficiency Diagrams for a Compressor-Driven Metal Hydride Heat Pump PDF

Finite-time thermodynamics is used to develop cooling power-efficiency diagrams for a compressor-driven metal hydride refrigerator. The two most important parameters - resistance to heat transfer between the reactors and the reservoirs and the thermal capacities of the system - are included in the analysis in a detailed and realistic way. The resistance to heat transfer due to low thermal conductivity inside the metal hydride reactor is appreciable and must be included in the analysis, unlike many other power systems. A simple quasi-steady-state model is used to investigate this effect and its relation to cooling power and efficiency of the system. Another interesting aspect of the metal hydride energy system is that increased finning outside the reactors reduces the efficiency - a trade-off exists between cooling power and coefficient of performance (COP). The effect of compression ratio on the system performance is also investigated. The finite-time thermodynamic analysis is a simple and powerful tool for investigating the effect of important system parameters on power and efficiency.

KEYWORDS: year 1997, Cooling, efficiency, metal hydride heat pumps, compressors, thermodynamics, heat flow, thermal capacity, thermal conductivity, cooling load, reactors, coefficient of performance, performance, calculating, refrigerators