Analytical solution to the equations for parallel-flow four-channel heat exchangers. Part 2: Double Zero Eigenvalue Case

This paper presents an analytical solution to the set of linear differential equations of the first order with constant coefficients describing the heat transport in a parallel-flow multi-channel heat exchanger for the case of double zero eigenvalue of the coefficient matrix of the set. This paper is a continuation of the author's previous work in which the case of simple eigenvalues of the coefficient matrix was analysed.