Controle aplicado a um sistema de aquecimento solar de água

Abstract

The research advances on the use of solar energy has enabled a several number of practical applications. One of those forms aims at heating water using solar radiation. From this perspective, the work in question aims at the development of a control system for water heating. Such system relies on the use of solar energy associated with an auxiliary resistive system. This development promotes, in addition to energy savings when compared to only resistive systems, advantages by making the use of a clean, renewable and abundant energy source. In this context, the use of two control systems, the On-Off and the proportional-integral (PI) for auxiliary resistance management. In relation to solar heating, an evacuated tube collector has been used to act under a mode of circulation by termosiphon. The fluid heated by solar radiation is stored in a boiler, where the auxiliary resistance works in order to increase the capacity and dynamics of the heater. Once the thermal system was defined, the dynamic model was obtained to concentrated parameters from the equations of physical behavior. The closed-loop control system was designed and simulated through MATLAB, PSIM and Proteus. The simulation and implementation results indicate that the control systems with the resistance are efficient in terms of the traceability of the reference, satisfying the demand for heating, besides minimizing the time required for it to reach the desired temperature. In this way the system is able to keep the fluid at setpoint temperature even with low solar radiation indexes on the collector.