Analytische Behandlung des Schmelzens und Erstarrens von Latentwaermespeichermaterialien in Rippenrohrgeometrien (Analytical Treatment of the Melting and Solidification of Latent Heat Store Materials in Finned Tube Geometries)

摘要

The heat transfer in a latent heat store was theoretically investigated using a heat exchanger element with a circumferentially finned tube in which the space between the fins is filled with storage material. An analytical method, employing Green's function, was developed to solve the two-dimensional transient heat conduction problem in inhomogeneous materials with simultaneous phase change. The Fourier heat conduction equation and the boundary conditions at the phase front are simultaneously fulfilled by the final solution, and the initial temperature is independent of a given phase change temperature. Only a very small number of time steps is required. Good agreement with data from the literature and with experiments is found. Diagrams for the design and optimization of latent heat stores with finned tubes were developed.