1. A computer-implemented method comprising modeling on a computer the time- and space-variable flow of multiple physical entities in a physical transport system, the physical entities comprising at least heat and moisture and the physical transport system comprising at least a solid phase and a gaseous phase, wherein the transport of one of the physical entities in the physical transport system affects the transport of one or more others of the physical entities transported in the physical transport system, the method comprising: a) providing a numerical transport code running on a computer, the numerical transport code having at least one time-variable input and a time-variable output related to the time-variable input; b) executing at least one calculation with the numerical transport code using a time- and space-variable input to the numerical transport code, the time- and space-variable input being related to the flow of the multiple physical entities in the physical transport system and obtaining at least one time-variable output response from the numerical transport code; c) identifying a mathematical functional relationship between the time- and space-variable input to the numerical transport code and the time-variable output response from the numerical transport code wherein the mathematical functional relationship identified comprises a convolution integral and the convolution integral includes a kernel function and the kernel function is identified as the indicial admittance of each of the multiple physical entities and the convolution integral is approximated with a discretized admittance comprising a sum of the product of discrete elements, each discrete element comprising the kernel function represented at one time point or spatial point, the discretized admittance being identified by a new inverse convolution from the discretized values as vectors of at least one given input and one given output; and d) generating a functionalized surrogate model of the physical transport system from the mathematical functional relationship identified, the functionalized surrogate model describing the time- and space-variable flow of the multiple physical entities in the physical transport system.