Approximate method for the solution to the equations for parallel and mixed-flow multi-channel heat exchangers

Abstract Approximate solutions for the steady state lumped linear formulation of heat transfer in multi-channel parallel-and-mixed-flow heat exchangers are obtained using polynomial approximations for the temperatures in each stream. Simple second and third degree polynomials result in acceptable errors when compared with the exact solutions. The method is especially suited for the practical treatment of exchangers with a large number of channels when other methods cease to be applicable. Extension of the method to treat the non-linear and transient problem is outlined.