Reducing energy demand and consumption in residential buildings is a global challenge. Heating of buildings consums nearly 40 % of global energy production. The largest energy consumers in buildings are the Heating, Ventilation and Air Conditioning (HVAC) systems. For reducing energy consumption, reliable control of HVAC systems is required.
When designing HVAC control systems, one should take into consideration a possibile sensor failure. Fault of any component in the control loop can increase the energy consumption, shorten lifespan of the rest of the equipment and usually degrade the living comfort. Single fault of the measurement and control component in the temperature control system leads to unwanted changes in the overall control loop, since controller does not receive accurate sensor data. A general practice during the sensor failure is to ''freeze'' the appropriate controller output. Usually, this is not the most appropriate solution, since it can cause larger temperature deviations in a particular room where sensor failure occurs.
The scope of the problem presented is to develop and evaluate fault-tolerant algorithm. Developed algorithm should be simple and suitable for implementaion in practice.
In this thesis, an innovative concept is proposed for maintaining high control performance when sensor failure occurs. It is based on the findings that valves openings and indoor temperatures are correlated. Therefore, we introduce the new functions which reflect interacting ratios of the valves openings in adjacent rooms. When sensor failure occurs, the proposed system claculates the control signal from the valve openings of the adjacent rooms.
We evaluated the algorithm on simulation-based experiment of building model, developed in MATLAB/Simulink programming environment. In the simulations we used real-world weather data for the city of Ljubljana, for a period of one year, with a sampling rate of one hour. It was shown high correlation between the fault-free system and the system with a single sensor fault while using the proposed algorithm. Since the algorithm is relatively simple and robust, it could be implemented in practice in a control systems with low processing power.