Modeling and Control the Temperature Inside a Public Building

Rooms in public buildings are characterized by alternating periods of use and non-use of these rooms, resulting from the limited number of working periods and the alternation of working and non-working days. The article presents measurements of thermal energy consumption in a selected office room and creates a thermal mathematical model of a room heated by a central heating. The dependences of the heat power consumed by the room as a function of the internal and external temperature for a steady state are given. Also a two-part transfer function describing the relation of the indoor temperature on the outdoor temperature and the radiator power is described. A radiator control algorithm was proposed to ensure thermal comfort in the room during working hours while saving energy during periods when no people are present in the room. Energy is saved by lowering the room temperature. Restoring thermal comfort uses a mathematical model of the room, thanks to which it is possible to estimate in simulation the hour of turning the heating on again in order to regain the thermal comfort temperature for a given hour. Based on the developed models, a method was developed and described for estimating the savings resulting from lowering the temperature inside the room during periods when no people are present in it. Savings are calculated as the difference between the energy supplied to the room in a hypothetical situation of no temperature reduction, calculated on the basis of a mathematical model of the room, and the actual, measured energy supplied to the room. The results obtained in the 2023/2024 heating season indicate the possibility of achieving from 20 % to 30 % thermal energy savings.