Modelling and analysis of thermal networks through subnetworks for multizone passive solar buildings

An efficient method is presented for the computer analysis in the frequency domain of multizone passive solar buildings. This method models heat conduction and convection between rooms, heat flows which are often not accounted for in order to reduce computation time. Heat transfer through a building is modelled by a thermal network. Massive walls are represented as two-port elements, analogous to non-inductive electrical transmission lines. Nodes representing exterior surfaces, whose temperatures do not have to be explicitly determined, are eliminated by the Norton theorem. The resulting simplified, but still complex networks, are split into subnetworks corresponding to rooms by removing a few simple components; the solutions for the subnetworks are found by means of the nodal formulation and are then coupled to give the system solution, without ever having to solve directly the initial complex network. There are no errors introduced by this decomposition process. This significantly simplifies the analysis of the building network and provides physical insight into the modelling and coupling of its subsystems.