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

A detailed mathematical model of a compressor driven metal hydride (CDMH) cooling system is presented. The model takes into account the transient characteristics of the coupled metal hydride reactors with external fins, reciprocating compressor and conditioned space. The model can be used for predicting the system performance during the initial pull-down as well as the stable cycling periods. Results are obtained for a 1 kW capacity air conditioning system using optimized reactors packed with Zr0.9Ti0.1Cr0.55Fe1.45 hydride. The COP's obtained are in the range of 1.7-2.2 depending on operating conditions while the specific cooling power obtained is about 600 U kg alloy(-1) h(-1). It is shown that in order to make these systems commercially viable it is important to select suitable materials with fast reaction kinetics. Since, system performance parameters can be predicted more effectively, the model can be used for design of optimized systems. (C) 2005 Elsevier Ltd and IIR. All rights reserved.