Optimización y control de sistemas de refrigeración mediante sistemas de almacenamiento con material de cambio de fase

Abstract

The demand of energy associated with refrigeration systems has become an essential in the energy structure. Whether in industry, as in domestic sphere, cold generation is a tool used worldwide, with several studies in the literature that detail its economic and environment impact. Given this footprint, new methods of cold generation and conservation are developed, among them, the development of the materials, design and technologies, as the used of thermal energy storage systems, can be cited. This Thesis, which is both theoretical and practical in nature, addresses the optimal operation of a vapour compression refrigeration cycle that adds an energy storage system focusing on this last component, although the others elements are also discussed. Among the objectives with more theoretical foundation we can mention the following: the storage system modelling, the design of a control strategy and the optimisation stage. Regarding the topics that will be covered it is worth mentioning the design and manufacturing of the storage system, and, as far as possible, the experimental application and evaluation of the theoretical results will be discussed. First of all, the models of the system elements will be exposed, being widely developed the storage system. A full-system simulator is made taking three cooling power as outputs: one generated at the evaporator, another which is transferred to the storage and the last released from the storage. The behaviour of the system is studied and the design and sizing of the storage are defined for the production. Secondly, a suitable cooling power control strategy is suggested. Energy efficiency objectives are also included on the plan, in order to make in order to make the cooling power demand feasible for each one of the power control signals would be achieved using the least possible external energy. Thirdly, a management system with the aim of providing optimal references to the low-level cooling power signals, according to the demand profile and the available cooling resources. The last one is defined as the sum of the power from the evaporator and the power released from the storage. Furthermore, being already known the cost of the temporal profile power generation, procedures to maximise economic efficiency are added. Eventually, there is an experimental plant of vapour compression refrigeration located in the laboratory of the Department of System and Automatic Control of the University of Seville to which the designed storage system has been added. The theoretical results, as far as possible, would be tested and evaluated on this plant.