Programski modul za optimizacijo vodenja ogrevanja v primeru izpadov temperaturnih senzorjev

NIKOLOVSKI, STEFAN (author), Klančar, Gregor (mentor), Vrančić, Damir (comentor)

Zmanjševanje porabe energije spada med najbolj pereče globalne izzive današnjega časa. Za ogrevanje zgradb se porabi približno 40 % svetovne proizvodnje energije. Med največje porabnike energije v zgradbah spadajo sistemi za ogrevanje, prezračevanje in klimatizacijo (angl. Heating, Ventilation and Air Conditioning, HVAC). Za varčno porabo energije je tako potrebno zagotoviti zanesljivo delovanje HVAC sistema. Pri načrtovanju vodenja HVAC sistemov je treba upoštevati, da se lahko vsak sestavni del opreme pokvari. Izpadi posameznih elementov lahko povečajo porabo energije, skrajšajo življenjsko dobo ostale opreme in praviloma zmanjšajo bivalno udobje. Izpad posameznih merilno-regulacijskih členov v sistemu, pri vodenju temperature, povzroči neželene spremembe v celotni regulacijski zanki, saj regulator ne dobi pravilen odčitek senzorja. Ob izpadu merilnega člena v nekem prostoru je običajna praksa, da ''zamrznemo'' izhod iz ustreznega regulatorja. Le-to pa ni vedno najbolj ustrezna rešitev, ker lahko s tem povzročimo znatna odstopanja temperature v prostoru. Problem, ki smo ga obravnavali v diplomskem delu, je razviti in testirati algoritem, ki bo uspešno nadomestil izpadli merilni člen. Omenjen algoritem mora biti enostaven in primeren za implementacijo v praksi. V diplomskem delu je predlagan inovativni koncept za določanje odprtosti izvršnega člena ob izpadu senzorja. Temelji na ugotovitvi, da so odprtosti ventilov v sosednjih prostorih in dejavniki, ki vplivajo na temperaturo posameznih prostorov, medsebojno korelirani. Zato vpeljemo nove funkcije, ki odražajo medsebojna razmerja odprtosti ventilov sosednjih prostorov. Pri izpadu določenega senzorja, predlagani sistem vklopi regulacijsko strukturo za vodenje temperature na osnovi izračunanih funkcij razmerij odprtosti ventilov. Algoritem smo preiskusili na simulacijskem modelu prostora, zgrajenem v programskem okolju MATLAB/Simulink. Za potrebe simulacije smo uporabili realne vremenske podatke za mesto Ljubljana za obdobje enega leta, s frekvenco vzorčenja ene ure. Rezultati so pokazali veliko ujemanje med sistemom brez izpadov in sistemom z odpovedjo enega merilnega člena ob uporabi predlaganega algoritma. Glede na relativno enostavnost in robustnost algoritma ga lahko vgradimo tudi v sistemih vodenja z nezahtevno procesorsko močjo.

• Language: Slovenian
• Keywords: temperaturni model, izpad senzorja, vodenje na osnovi razmerja izvršnih členov, HVAC sistemi
• Work type: Undergraduate thesis
• Organization: FE - Faculty of Electrical Engineering
• Year: 2015
• PID: 20.500.12556/RUL-30720
• Publication date in RUL: 24.04.2015

Secondary language

• Language: English
• Title: Program module for optimisation of heating control in case of temperature sensors failure

Abstract

Reducing energy demand and consumption in residential buildings is a global challenge. Heating of buildings consums nearly 40 % of global energy production. The largest energy consumers in buildings are the Heating, Ventilation and Air Conditioning (HVAC) systems. For reducing energy consumption, reliable control of HVAC systems is required. When designing HVAC control systems, one should take into consideration a possibile sensor failure. Fault of any component in the control loop can increase the energy consumption, shorten lifespan of the rest of the equipment and usually degrade the living comfort. Single fault of the measurement and control component in the temperature control system leads to unwanted changes in the overall control loop, since controller does not receive accurate sensor data. A general practice during the sensor failure is to ''freeze'' the appropriate controller output. Usually, this is not the most appropriate solution, since it can cause larger temperature deviations in a particular room where sensor failure occurs. The scope of the problem presented is to develop and evaluate fault-tolerant algorithm. Developed algorithm should be simple and suitable for implementaion in practice. In this thesis, an innovative concept is proposed for maintaining high control performance when sensor failure occurs. It is based on the findings that valves openings and indoor temperatures are correlated. Therefore, we introduce the new functions which reflect interacting ratios of the valves openings in adjacent rooms. When sensor failure occurs, the proposed system claculates the control signal from the valve openings of the adjacent rooms. We evaluated the algorithm on simulation-based experiment of building model, developed in MATLAB/Simulink programming environment. In the simulations we used real-world weather data for the city of Ljubljana, for a period of one year, with a sampling rate of one hour. It was shown high correlation between the fault-free system and the system with a single sensor fault while using the proposed algorithm. Since the algorithm is relatively simple and robust, it could be implemented in practice in a control systems with low processing power.

• Keywords: temperature model, sensor fault, actuators ratios based control, HVAC system