Intermittent heatind system control based on the quadratic optimization principle

This paper deals with an optimal control algorithm which enables to regulate the heating installation of a building with discontinuous occupation. The control structure is based on the quadratic optimization principle. It seems to have several characteristics that are worth mentioning, in particular its simple calculating method and its easy installation. As opposed to the optimal control algorithms based on the minimum principle, the above-mentioned algorithm can be set up in microprocessors of very low capacity. This should make it possible to incorporate it easily into building energy management systems. One optimal control model using this algorithm has been developed and tested by simulation. The results obtained showed that this control model was able both to forecast the preheating time precisely and to control perfectly the temperatures of the buildings when occupied, whatever the external temperature or the maximum heating installation power. Simulations for a specific heating season have also been performed by using respectively the optimal control and one intermittency scheduler (the pre-heat phase starts at the same time all over the year) associated with a P.I. controller. As compared to the latter, the optimal control provides not only more reliable comfort, but also high energy conservation. Furthermore, the method described above makes it possible for any experienced user to elaborate rapidly optimal control models suitable for many different types of systems.