We extend our previous work on the dynamics of regenerators in the harmonic
approximation by including the enthalpy flow and nonideal gas behavior. Th
e derivation is based on the energy conservation of the matrix and of the g
as, the flow resistance of the matrix, and mass conservation. The model is
one-dimensional. Expressions are derived for the gradients of the regenerat
or parameters which can be integrated directly from the boundary conditions
. It is not necessary to assume an initial temperature profile. This provid
es a very fast and convenient tool for designing cryocoolers; such as pulse
-tube refrigerators. (C) 2001 Elsevier Science Ltd. All rights reserved.