An accurate thermal calculation is the key for a proper high efficiency building. In hot weather conditions, such as the Italian ones, the steady state models are not suitable, since during the day there are sensible variation in the boundary conditions. An example can be seen in the external temperatures fo July in Brescia. The average monthly temperature (use for steady state calculation) is 22.2°C, this means that with a cooling set point of 26°C, the consumption is zero.
This is not realistic. The problem is that using steady state models peaks are ignored. Until 2017 the only alternative to steady state models was the “whole building simulation” or “dynamic simulation”. Now a new code has been published for the so called “hourly dynamic simulation”.
This new approach permits to have a more accurate thermal calculation, considering the peaks, the user behaviour and the building inertia, but without the big computational effort that is required we carrying out a whole building simulation.
Furthermore the dynamic hourly simulation can provide information on comfort, that are not available with the traditional steady state. At the same time the same model can be used to verify the compliance with the legal requirements. This is not possible if using a whole building simulation program.