Energy and Buildings, Vol.138, 415-431, 2017
Accurate model reduction and control of radiator for performance enhancement of room heating system
Since radiator takes an important role in controlling indoor air temperature and heat output of district heating system, efficient control of radiator is essential for thermal comfort and energy conservation. The governing equation of radiator heat transfer is a partial differential equation (PDE), which is not suitable for controller design. In this paper, an accurate model reduction method was established to reduce the radiator model. Comparison of the reduced and PDE models via Bode diagrams shows good approximation of the reduced model. The integrated model of room heating system was developed based on the reduced radiator model. In order to enhance the dynamic performance of room heating system, a new control algorithm, the two-degrees-of-freedom H-infinity control was proposed. The reference tracking and disturbance rejection performances of room heating system with H-infinity and PI controllers were compared. Dynamic performances of closed-loop system controlled by the two control algorithms under capacity parameter uncertainties were analyzed to verify the robustness of the proposed control algorithm. Results show that the proposed two-degrees-of-freedom H-infinity controller can ensure better reference tracking and disturbance rejection performances even when system uncertainty exists. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Radiator model reduction;Model comparison;Room heating system;Robust control;Reference tracking;Disturbance rejection