Experimental evaluation of fuzzy controllers for the temperature control of the secondary refrigerant in a liquid chiller

Silva, Flávio Vasconcelos da; Filho, Lincoln C. Neves; Silveira, Vivaldo

doi:10.1016/j.jfoodeng.2005.03.061

Cited by 19 publications

(11 citation statements)

References 4 publications

(2 reference statements)

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“…The developed fuzzy controller acted consistently, corroborating with the results observed by SILVA et al (2006), inter-relating the linguistic variables determined by a expert, allowing a controlled deviation of the reference value of the PID controller. This deviation is larger, the smaller the difference between the air temperature at the evaporator inlet (T_air_Evap) and the air temperature at the center of the chamber (T_Center).…”

Section: Fuzzy Control Strategysupporting

confidence: 81%

“…In industrial processes, the use of fuzzy control has increased greatly in recent decades, especially in those difficult mathematical modeling processes, due to its ability to function in a system based solely on expert knowledge, and also to interrelate all the variables process (SILVA et al, 2006). HUANG et al (2010) conducted a comprehensive review of the literature on soft computing methods, among which the application of fuzzy logic in precision agriculture.…”

Section: Introdutionmentioning

confidence: 99%

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System for studies of control strategies applied in the refrigerated chambers

et al. 2011

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ABSTRACT:The process of cold storage chambers contributes largely to the quality and longevity of stored products. In recent years, it has been intensified the study of control strategies in order to decrease the temperature change inside the storage chamber and to reduce the electric power consumption. This study has developed a system for data acquisition and process control, in LabVIEW language, to be applied in the cooling system of a refrigerating chamber of 30m 3 . The use of instrumentation and the application developed fostered the development of scientific experiments, which aimed to study the dynamic behavior of the refrigeration system, compare the performance of control strategies and the heat engine, even due to the controlled temperature, or to the electricity consumption. This system tested the strategies for on-off control, PID and fuzzy. Regarding power consumption, the fuzzy controller showed the best result, saving 10% when compared with other tested strategies. KEYWORDS: energy-saving, PID controller, fuzzy controller, cold storage. SISTEMA PARA ESTUDOS DE ESTRATÉGIAS DE CONTROLE APLICADAS EM CÂMARAS FRIASRESUMO: O processo de armazenamento refrigerado em câmaras contribui, em grande parte, para a qualidade e a longevidade dos produtos. Nos últimos anos, têm-se intensificado os estudos de estratégias de controle com a finalidade de diminuir a variação da temperatura dentro da câmara de armazenamento e de reduzir o consumo de energia elétrica. Neste trabalho, foi desenvolvido um sistema para aquisição de dados e controle do processo, em linguagem LabVIEW, para ser aplicado no sistema de refrigeração de uma câmara frigorífica de 30m 3 . A utilização da instrumentação e do aplicativo desenvolvido possibilitou a realização de experimentos científicos, com o objetivo de estudar o comportamento dinâmico do sistema de refrigeração, comparar o desempenho das estratégias de controle da máquina térmica, tanto em função da temperatura controlada, quanto ao consumo de energia elétrica. Neste sistema, foram testadas as estratégias de controle liga-desliga, PID e fuzzy. Em relação ao consumo de energia elétrica, o controlador fuzzy obteve o melhor resultado, economizando 10% em relação às outras estratégias testadas. PALAVRAS-CHAVE: economia de energia, controlador PID, controlador fuzzy, armazenamento refrigerado.

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Section: Fuzzy Control Strategysupporting

confidence: 81%

Section: Introdutionmentioning

confidence: 99%

System for studies of control strategies applied in the refrigerated chambers

et al. 2011

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“…The pasteurized product, whose temperature was above the set point, was sent back to the other side of the regeneration section to be cooled off. The last stage is the cooling section, where propylene glycol at 50% m/m coming from a chiller (Silva et al . 2006) was responsible to cool the product down to storage temperature.…”

Section: Methodsmentioning

confidence: 99%

Design and Performance of Conventional and Fuzzy Controls for a High Temperature Short Time Pasteurization System

Berto¹,

Silveira

2011

J Food Process Engineering

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Fuzzy control was applied in a high-temperature short time (HTST) pasteurization system and experimentally evaluated and compared with proportional-integralderivative (PID)/feedback and PID/feedback/feedforward controllers. The product, a juice model solution, was pasteurized for 91C/40 s in a three-stage plate heat exchange (regeneration, heating and cooling sections). Hot water and propylene glycol were responsible to heat and cool the product, respectively. A control system was designed to assure the pasteurization temperature manipulating the hot fluid flow rate. Controllers were evaluated by means of dynamic behavior of the pasteurization temperature and performance criteria after the imposed step changes of the product inlet temperature. Configured controllers kept the process temperature within HTST requirements, having a variation of Ϯ0,5C, and the similar values of performance criteria indicate an efficiency for all three tested controllers. PRACTICAL APPLICATIONSThe continuous need for better food products, standardized within the consumer demands, has expanded the applications and the search for solutions using automation and control techniques. The use of control strategies and automation in chemical, petroleum and other industrial processes are more intensive as compared with the same applications in food industries. The complex execution of experimental tests in lab-scale or pilot plants is the main reason for the great number of simulations in the process control area. Based on the importance of accomplishing experimental errors and uncertainties, this paper results from an extensive research developed in a pilot plant of HTST process. Theoretical methods for tuning controllers were applied and evaluated. Conventional controllers (PID/feedback and PID/ feedback/feedforward) were tuned and compared with fuzzy control, one of the most recognized nonconventional controllers. Results showed that the requirements to maintain pasteurization temperature after changes in inlet process conditions were performed in all three strategies, indicating the accomplishment of the research purpose.cessing. It is used to sterilize a wide range of liquid foods, including milk, fruit juices and concentrates, cream, yogurt, salad dressing, egg and ice cream mixes (Fellows 2000). Orange juice pasteurization studies have been demonstrated that lower temperatures are sufficient to inactivate microorganism activities, although, to prevent the loss of cloudiness, bs_bs_banner Journal of Food Process Engineering ISSN 1745-4530 58 Journal of Food Process Engineering 36 (2013) 58-65

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“…The fuzzification subsystem measures the values of input variables, performs a scale mapping that transfers the range of values of input variables into corresponding universes of discourses, and performs the function of fuzzification that converts input data into suitable linguistic values which may be viewed as labels of fuzzy sets [22,23,25] In the inference mechanism, fuzzy results are inferred from the memberships of fuzzy sets with the aid of the knowledge base. In the inference subprocess, the truth value for the premise of each rule is computed, and applied to the conclusion part of each rule.…”

Section: The Basis Of the Fuzzy Expert Systemmentioning

confidence: 99%

Fuzzy Modeling of Performance of Counterflow Ranque-Hilsch Vortex Tubes with Different Geometric Constructions

Dinçer

Taşdemir

Baskaya

et al. 2008

Numerical Heat Transfer, Part B: Fundamentals

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In this article, we present the development of a fuzzy expert system (FES) for fuzzy modeling of the performance of counterflow Ranque-Hilsch vortex tubes for different geometric constructions. Experimental values were obtained from a detailed experimental investigation. With these experimental values, FES models of the Ranque-Hilsch vortex tube behavior were designed using the MATLAB 6.5 fuzzy logic toolbox in Windows XP running on an Intel 3.0-Ghz PC. For this process P, N, n, and L/D were chosen as input and DT h , DT c , DT as output parameters. FES results agree well with experimental data. It was found that the coefficient of multiple determination (R 2 value) between the actual and fuzzy predicted data is DT h ¼ 0.9801, the R 2 value for DT c values is 0.9841, and the R 2 value for DT values is 0.9748.

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Experimental evaluation of fuzzy controllers for the temperature control of the secondary refrigerant in a liquid chiller

Cited by 19 publications

References 4 publications

System for studies of control strategies applied in the refrigerated chambers

System for studies of control strategies applied in the refrigerated chambers

Design and Performance of Conventional and Fuzzy Controls for a High Temperature Short Time Pasteurization System

Fuzzy Modeling of Performance of Counterflow Ranque-Hilsch Vortex Tubes with Different Geometric Constructions

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