Daily characteristics of air temperature and solar irradiation-input data for modelling of thermal behaviour of buildings

Usually published simple building indoor temperature prediction methods oriented to the passive solar design often suppose the idealized monthly mean daily courses of the outdoor thermal excitations—solar irradiation and outdoor temperature. The thermal response to the interdiurnal changes of weather situations are either not considered or only schematically considered in those methods. The concept proposed in this paper enables detailed and simple indoor temperature calculation considering the influence of weather changes during each of the previous days. Thermal behaviour of buildings, usually modelled by a system of differential equations, can be modelled in many cases by only one differential equation. The input data for the solution of the differential equation are hourly values of the solar irradiation and outdoor air temperature. Assuming that the daily courses of the climatic elements can be approximated by simple functions, the thermal behaviour of a building can be simulated as a response to daily excitations of the outdoor environment—sums of solar irradiation and temperatures at 3 observation times.