In this thesis a supervisory control system for an academic building is presented with a specific focus on comfort indexes such as temperature and air quality control. The proposed supervisory control system is a solution that has the same benefits as nowadays installed system enriched with more features such as scalability and communication with different types of control architectures. Nowadays, PoliMi Building 25 has control system for temperature and air quality, whose feedback for the operator is the usual PID variables, like set point (SP), process value (PV) and controller output (U). However, there is a difference between this control problem and typical industrial control problems, in which it is desired to reach a specific value for a physical variable. In fact, in this case the system should provide comfort for the users, but for this purpose it is first needed to express comfort as a quantity. Another disadvantage of the actual control architecture is its poor scalability and capacity to connect with other devices. This is mainly because the actual control system is a specific solution for temperature and air quality control with unique brand devices. However, in practice the constant evolution of the building requirements calls for a collaboration between the existing one and the most innovative ones coming from different brand devices and focused not only on temperature and air quality, but even on the processes of each laboratory, physical security, fire prevention systems, etc. Finally, in case that the operator wants to export the data. This is currently done with a sampling time of 30 minutes, making it difficult to analyze and study the information that the system can provide. The solution presented in this project overcome all these problems and a closer look on how it is done can be found. Starting from a distributed sensors structure all over the rooms that need be controlled, with a collector for the data of the sensors, which later will send the information by a communication protocol to a graphical interface so that the operator has a feedback of the system. A Supervisory Control and Data Acquisition (SCADA) system solution is presented. This technology is normally used for industrial process (production), and even though this is not a so different system, it is not applied that much for thermal and air quality comfort. The SCADA system provides scalability with a large group of brands and devices to work with that can be easily attached by the different communication drivers. The SCADA systems can be applied to different architectures, like a self-server or server and multi-client structure, depending on the dimension of the application. For the specific case of this thesis a self-server structure is implemented. All the data of the SCADA is stored in the selected server, which later can be archived, with a configurable sample time, for future analysis. An approach to quantify the comfort in a room will be presented. The computation depends of an eligible number of comfort features, for the case of this project there are two comfort features: temperature and air quality. The proposed solution will have all the features to solve the problematic but scaled to a DEMO as the control structure will be simulated by MATLAB and the SCADA will run in a virtual machine with a limited memory (50 GB). Even though, this is enough to prove the benefits of the solution.
In questa tesi viene presentato un Sistema di controllo supervisivo applicato ad un edificio ad uso accademico, con attenzione specifica agli indici di comfort relativi alla temperatura ed al controllo della qualità dell’aria. Il controllo supervisivo proposto presenta le stesse caratteristiche dei sistemi attualmente all’avanguardia, presentando vantaggi dalla scalabilità alla comunicazione con differenti tipi di architetture di controllo. Oggigiorno, l’edificio 25 del Politecnico di Milano è equipaggiato con un sistema di controllo per la temperatura e la qualità dell’aria. Il feedback di tale sistema verso l’operatore è costituito dalle variabili tipiche di un semplice controllo PID, quali il suo set-point (SP), la sua variabile controllata (PV) e la variabile manipolata (U), rispecchiando un classico scenario di controllo industriale. A differenza di tale scenario, però, in questo scenario di controllo deve esser posta maggior attenzione alla definizione stessa del comfort dell’utente, per il quale deve essere proposta uno o più indici adeguati. Un ulteriore svantaggio dell’architettura di controllo attuale si può trovare nel suo basso livello di scalabilità e di connettività con diversi dispositivi. Questo fattore è dovuto principalmente alla specificità della soluzione dell’attuale sistema di controllo, dotato di brand specifici configurati a sistema chiuso. Oggigiorno, le soluzioni di controllo più adeguate sono immerse in uno scenario caratterizzato da una continua evoluzione, per cui diventa necessaria la possibilità di interfacciare vecchie soluzioni con i nuovi dispositivi offerti dal mercato. Tali dispositivi presentano una varietà di misure innovative e complesse, quali misure antifurto, prevenzione incendi ecc. Infine, nel caso in cui l’operatore desideri esportare i dati raccolti dalla rete di sensori, il tempo di campionamento attuale è limitato ad una media di 30 minuti a causa dei protocolli di comunicazione utilizzati. Questo tempo di campionamento rende difficile l’analisi di specifiche dinamiche termo-fisiche dell’edificio in questione, quali le dinamiche dei sistemi di generazione dell’energia termica. La soluzione presentata è in grado di ovviare a questo problema. Una rete di sensori distribuita nelle diverse stanze dell’edificio sarà governata da un data collector, che a sua volta sarà in grado di trasmettere – sotto richiesta – i dati ad un sistema di data monitoring al fine di rendere l’analisi di tali dati facilmente fruibile all’operatore. Una soluzione SCADA (Supervisory Control and Data Acquisition) è presentata nella presenta tesi. Questa soluzione, tipicamente applicata in ambiti industriali, trova un ottima applicazione nel contesto di controllo oggetto di questo studio. Il sistema SCADA fornisce la necessaria scalabilità verso un ampio spettro di diversi gruppi di dispositivi ed offre la concreta possibilità di interfacciarli verso un unico sistema centralizzato. Il sistema SCADA offre inoltre la possibilità di configurare la rete sotto diverse architettura, attribuendo ruoli di self-server, server o multi-client in base all’estensione dell’applicazione. Per il caso specifico di questa tesi, una struttura self-server è implementata. Tutti i dati dello SCADA vengono salvati in tale server per poter poi esser eventualmente archiviati per future analisi. Uno specifico approccio per quantificare il comfort dell’utente nella stanza sarà presentato. Tale calcolo dipende da uno specifico numero di variabili. Per questo caso, vengono considerate due quantità, ovvero la temperatura ed il livello di CO2 nell’aria. La soluzione proposta presenterà tutte le funzioni necessarie alla soluzione delle problematiche presentate. L’applicazione di tale soluzione sarà presentata tramite una demo, simulando la struttura di controllo in ambiente MATLAB, mentre il sistema SCADA sarà fatto girare su una macchina virtuale con memoria limitata (50 GB). La configurazione di tale test sarà sufficiente a provare i benefici della soluzione presentata.
Scada system for thermal and air quality comfort in an academic building
ORDONEZ MERA, MIGUEL ANGEL
2018/2019
Abstract
In this thesis a supervisory control system for an academic building is presented with a specific focus on comfort indexes such as temperature and air quality control. The proposed supervisory control system is a solution that has the same benefits as nowadays installed system enriched with more features such as scalability and communication with different types of control architectures. Nowadays, PoliMi Building 25 has control system for temperature and air quality, whose feedback for the operator is the usual PID variables, like set point (SP), process value (PV) and controller output (U). However, there is a difference between this control problem and typical industrial control problems, in which it is desired to reach a specific value for a physical variable. In fact, in this case the system should provide comfort for the users, but for this purpose it is first needed to express comfort as a quantity. Another disadvantage of the actual control architecture is its poor scalability and capacity to connect with other devices. This is mainly because the actual control system is a specific solution for temperature and air quality control with unique brand devices. However, in practice the constant evolution of the building requirements calls for a collaboration between the existing one and the most innovative ones coming from different brand devices and focused not only on temperature and air quality, but even on the processes of each laboratory, physical security, fire prevention systems, etc. Finally, in case that the operator wants to export the data. This is currently done with a sampling time of 30 minutes, making it difficult to analyze and study the information that the system can provide. The solution presented in this project overcome all these problems and a closer look on how it is done can be found. Starting from a distributed sensors structure all over the rooms that need be controlled, with a collector for the data of the sensors, which later will send the information by a communication protocol to a graphical interface so that the operator has a feedback of the system. A Supervisory Control and Data Acquisition (SCADA) system solution is presented. This technology is normally used for industrial process (production), and even though this is not a so different system, it is not applied that much for thermal and air quality comfort. The SCADA system provides scalability with a large group of brands and devices to work with that can be easily attached by the different communication drivers. The SCADA systems can be applied to different architectures, like a self-server or server and multi-client structure, depending on the dimension of the application. For the specific case of this thesis a self-server structure is implemented. All the data of the SCADA is stored in the selected server, which later can be archived, with a configurable sample time, for future analysis. An approach to quantify the comfort in a room will be presented. The computation depends of an eligible number of comfort features, for the case of this project there are two comfort features: temperature and air quality. The proposed solution will have all the features to solve the problematic but scaled to a DEMO as the control structure will be simulated by MATLAB and the SCADA will run in a virtual machine with a limited memory (50 GB). Even though, this is enough to prove the benefits of the solution.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/149967