Solar contribution to space heating

Summary

The solar contribution to space heating and cooling is evaluated through an analytical procedure. The method used simulates the building as a thermal network in which each node corresponds to the centre of a room and each mesh arm to a wall; building materials and frames are explicitly taken into account. The network is excited by a set of generators corresponding to external excitations (e.g. environmental temperature, solar flux, etc.) which are described by a truncated Fourier series. The network is resolved by an analytical method through the matrix formalism and gives either the time diagrams of indoor temperatures in each room, or the diagrams of the auxiliary energy required to maintain a set room temperature. The application to a residential environment is presented as an example and is discussed in relation to a passive retrofitting design. The results are briefly compared with those obtained through established procedures, to give evidence of the occurrence of strong fluctuations on the average values which significantly influence the conditions of comfort. The method can be implemented at the level of microcomputers.