Hybrid Modeling of a Solar Cooling System

Solar systems are deeply affected by weather conditions and their main energy source, irradiation, cannot be manipulated. This paper describes a solar cooling system located at the University of Almería, Spain. The system is composed by a solar collector, a gas heather, and two serial connected tanks to storage hot water. They are used as energy sources for an absorption machine whose objective is to obtain chilled water for the fan-coil system. All these components are included or excluded from the cooling system by means of switching valves and activating or deactivating signals. The switching among different configuration modes in real time increases the system challenge to be modeled or controlled, due to the mix of both discrete signals and continuous dynamics. In this paper, a model for each energy source is developed and afterwards they are integrated into one state-space model used to obtain a hybrid model. This hybrid model is able to simulate the different configuration modes of the solar cooling system. Some real tests are presented.