This thesis is focused on the development of a Hybrid MPC for the control of the heating system with radiators of a 3-floors building. This control strategy is implemented to minimize the thermal power exchanged by the radiators with the room, guaranteeing the user’s thermal comfort. To generate the hybrid MPC, it is required to build a hybrid model, able to describe the dynamics that govern the thermal exchanges that occur in the different zones. For the sake of simplicity and for data availability, only one zone per floor is considered, 3 total zones, and one radiator per zone. The thermal model is developed with lumped parameters and it is sufficiently detailed to describe the prevailing dynamics of the system, moreover, this modelling choice allows a stronger physic representativeness of the results, on which the predictive control strategy will be developed. At first, the model is implemented in Matlab environment, in which a parameters identification is carried out. The identified parameters are those relative to the thermal characteristics of walls, pavements and ceiling and the remedial coefficient of the thermal power issued by the radiators. The identification is performed through a Grey-Box model, by analysing the 3 floors separately, to then report the estimated parameters in the whole model of the building. Subsequently, in Hysdel environment, through logical propositions, the hysteresis behaviour, that characterizes the progress of the temperature of each zone, is described and the model is made hybrid. To describe the hysteresis behaviour, Boolean variables and expressions related to the propositional calculus are exploited, and then are connected to the continuous thermal dynamics to generate an MLD model (Mixed Logical Dynamical), useful to the hybrid MPC. Once the hybrid MPC is developed, some simulations are performed, and the results obtained are compared with those got from the same hybrid system but regulated by a simple logic ON-OFF, and the advantages gained with the strategy of the predictive control are shown. Finally, two performances analysis are carried out, the first based on different constructive features of the building while the second based on different temperature set points imposed to the hysteresis. To conclude a robustness analysis, of the predictive control developed, is performed.
La presente tesi è dedicata allo sviluppo di un MPC ibrido nel contesto del controllo dell’impianto di riscaldamento a radiatori di un edificio a 3 piani. Questa strategia di controllo è implementata con il fine di minimizzare la potenza termica scambiata dai radiatori con la stanza garantendo allo stesso tempo il comfort termico dell’utente. Si è scelto di generare un MPC ibrido, poiché il modello, in grado di descrivere le dinamiche che regolano gli scambi termici che avvengono all’interno delle diverse zone, è ibrido. È stata considerata una sola zona per piano, quindi 3 zone totali, ed un radiatore equivalente per zona. Il modello termico è stato sviluppato a parametri concentrati ed è sufficientemente dettagliato da riuscire a descrivere le dinamiche dominanti del sistema; inoltre questa scelta modellistica permette una maggiore rappresentatività fisica dei risultati sulla base dei quali la strategia di controllo predittiva sarà sviluppata. Inizialmente, il modello è sviluppato in ambiente Matlab in cui è stata effettuata un’identificazione di parametri ignoti. I parametri identificati sono quelli relativi alle caratteristiche termiche di pareti, pavimenti, tetto e i coefficienti correttivi della potenza termica emanata dai radiatori. L’identificazione è fatta con un modello Grey-Box, analizzando i 3 piani separatamente, per poi riportare i parametri stimati nel modello complessivo dell’edificio. Successivamente, in ambiente Hysdel è descritto, tramite proposizioni logiche, il comportamento ad isteresi caratterizzante l’andamento della temperatura di ogni zona e quindi il modello è reso ibrido a tutti gli effetti. Nel descrivere il comportamento ad isteresi, sono sfruttate variabili booleane ed espressioni relative al calcolo proposizionale, messe poi in relazione con le dinamiche termiche continue per poter creare un modello di tipo MLD (Mixed Logical Dynamical) sfruttabile dal MPC ibrido. Dopo aver sviluppato l’MPC ibrido, vengono svolte alcune simulazioni, ed i risultati ottenuti sono confrontati con quelli ricavati dallo stesso sistema ibrido regolato da una semplice logica ON-OFF e vengono evidenziati i vantaggi, in termini di risparmio energetico, raggiunti con la strategia del controllo predittivo. Infine, vengono effettuate due analisi delle performance basate su differenti caratteristiche costruttive dell’edificio e su differenti set point di temperatura imposti. Per concludere viene effettuata un’analisi della robustezza del sistema di controllo predittivo sviluppato.
Development of a hybrid MPC technique to increase the energy efficiency of a building heating system
CERUTI, FEDERICO
2018/2019
Abstract
This thesis is focused on the development of a Hybrid MPC for the control of the heating system with radiators of a 3-floors building. This control strategy is implemented to minimize the thermal power exchanged by the radiators with the room, guaranteeing the user’s thermal comfort. To generate the hybrid MPC, it is required to build a hybrid model, able to describe the dynamics that govern the thermal exchanges that occur in the different zones. For the sake of simplicity and for data availability, only one zone per floor is considered, 3 total zones, and one radiator per zone. The thermal model is developed with lumped parameters and it is sufficiently detailed to describe the prevailing dynamics of the system, moreover, this modelling choice allows a stronger physic representativeness of the results, on which the predictive control strategy will be developed. At first, the model is implemented in Matlab environment, in which a parameters identification is carried out. The identified parameters are those relative to the thermal characteristics of walls, pavements and ceiling and the remedial coefficient of the thermal power issued by the radiators. The identification is performed through a Grey-Box model, by analysing the 3 floors separately, to then report the estimated parameters in the whole model of the building. Subsequently, in Hysdel environment, through logical propositions, the hysteresis behaviour, that characterizes the progress of the temperature of each zone, is described and the model is made hybrid. To describe the hysteresis behaviour, Boolean variables and expressions related to the propositional calculus are exploited, and then are connected to the continuous thermal dynamics to generate an MLD model (Mixed Logical Dynamical), useful to the hybrid MPC. Once the hybrid MPC is developed, some simulations are performed, and the results obtained are compared with those got from the same hybrid system but regulated by a simple logic ON-OFF, and the advantages gained with the strategy of the predictive control are shown. Finally, two performances analysis are carried out, the first based on different constructive features of the building while the second based on different temperature set points imposed to the hysteresis. To conclude a robustness analysis, of the predictive control developed, is performed.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/152584