Reversed Brayton cycle for food freezing at very low temperatures: Energy performance and optimisation

Biglia, Alessandro; Comba, Lorenzo; Fabrizio, Enrico; Gay, Paolo; Mannini, Achille; Mussinatto, Adriano; Aimonino, Davide Ricauda

doi:10.1016/j.ijrefrig.2017.05.022

Cited by 21 publications

(3 citation statements)

References 45 publications

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“…The cryogenic turbo-based refrigerator, which consists of the reverse Brayton cycle, Claude cycle, and Kapitza cycle etc., is extensively applied in many areas, such as the controllable nuclear fusion [1], air separation and liquefaction [2], Zero Boil Off liquid hydrogen storage [3], low temperature environmental simulator [4], superconducting [5,6], food industry [7,8], and heat pump [9]. Because of the low operational temperature, the thermal capacity of system components, and so on, the cooling process of a cryogenic turbo-based refrigerator is quite long and complex [4,7]. Moreover, the cryogenic refrigerator usually operates under varying conditions, which makes the dynamic performance more complex and unpredictable.…”

Section: Introductionmentioning

confidence: 99%

Simulation and Evaluation on the Dynamic Performance of a Cryogenic Turbo-Based Reverse Brayton Refrigerator

2019

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In this study, a cryogenic turbo-based refrigerator, with high-speed foil gas bearing turboexpander and plate-fin heat exchanger, was presented. For the cooling process of a cryogenic refrigerator is long and complex, the efficient simulation of the dynamic performance is vital for its evaluation and operation. It is difficult to achieve this purpose. Because the cryogenic refrigerator will go through great temperature changes, resulting in dynamic performances of components going to complexity. In this article, the turboexpander was simulated using CFX, and the matching models with expansion works of consumption and utilization were unified and modified. With numerical calculation of heat exchanger, the dynamic simulation model of the refrigerator was improved via MATLAB code. The calculation method of the required input energy of the refrigerator in cooling processes was proposed based on the simulation and integration. The energy efficiency and economy cost of the refrigerator were evaluated under different operation modes. The refrigerator with a motor was more stable than the one with a blower. The refrigerator was tested under different conditions, the results of which agreed well with simulation data. The simulation method is efficient to serve practical applications, improve energy efficiency and reduce costs.

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Section: Introductionmentioning

confidence: 99%

Simulation and Evaluation on the Dynamic Performance of a Cryogenic Turbo-Based Reverse Brayton Refrigerator

2019

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“…Freezing time relies on several factors, including food composition, the temperatures of the food, and the temperature and velocity of the air (Biglia et al, 2017). Numerical modeling of shrimp freezing in tunnel IQF freezer was studied by Narsaiah, Bedi, Ghodki, and Goswami (2021).…”

Section: Introductionmentioning

confidence: 99%

Phase change material‐assisted freezing of tuna: Impact on freezing process and thawing loss

Hakim

Fauzi

Pranoto

2022

J Food Process Engineering

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Due to slow freezing, freezing fresh fish in a chest freezer often leads to deterioration while products are thawed. Many approaches have been conducted to deal with it. One of them is the application of Phase Change Material (PCM) in refrigeration systems. This study aims to investigate the ability of PCM to accelerate the freezing of fish in the household freezers. The tuna used was stored in the freezer with PCM, which was put on a surface wall cabinet then compared with storage in the freezer without PCM. Besides, the door of the freezer was also opened frequently (three times a day, 1 hr each time) to find out the effect of fluctuating temperatures and freezing operations for 60 hr. The parameters observed include the evolution temperature of the air cabinet and fish, energy consumption of the freezer, and thawing loss. Results showed that PCM accelerated the cooling rate of air cabinets and fish but could not suppress the fluctuation temperature. The quality of the frozen tuna improved, which was indicated by a decreased thawing loss parameter from 3.10% to 1.76%. Overall, this finding revealed PCM has significant potential to improve the fish freezing process. Practical Applications The household chest freezer is widely used to freeze fish by small and medium‐sized enterprises (SMEs). The most important factors in freezer preferences are simple operations and low energy consumption. But, the freezer worked at slow freezing, which caused higher thawing losses of the product. Hence, the application of PCM to the household freezer potentially improves the freezing process of the fish. So, sellers and retailers of fish could maintain their products without replacing the freezer with an advanced one.

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“…O meio de troca térmica age de forma a remover calor do produto por convecção e, em geral, os processos industriais empregam ar como meio, devido ao baixo custo e ao baixo risco de contaminação de produto e ambiente. Embora haja processos que empregam convecção natural, a maioria das aplicações do ar como meio de troca térmica envolvem convecção forçada, sendo que esta pode ser utilizada tanto para processos em batelada quanto contínuos (BIGLIA et al, 2017).…”

Section: Congelamento De Alimentosunclassified

Congelamento de alimentos em condições operacionais alternativas

de Paula Gonçalves

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pela concessão da bolsa de estudos (processo número 140704/2017-5).À Japanese Student Service Organization (JASSO), pela concessão da bolsa referente ao período sanduíche no Japão.À Unicamp, à FEA, e à Tokyo University of Agriculture and Technology pela oportunidade.Aos professores Vivaldo Silveira Junior e Seishu Tojo, pela oportunidade, orientação, paciência e confiança.Aos membros da banca examinadora, pela contribuição para a melhoria do trabalho.Aos companheiros do Laboratório de Automação e Controle de Processos de Alimentos, do Agro-Environment Control and Renewable Energy Laboratory e do programa La-CEP, pela parceria, incentivos e sugestões.Aos meus pais, pelo companheirismo, apoio e confiança.À minha família e aos amigos do Eletrota, Taekwondo Unicamp, ECA e BSGI, pela torcida e carinho. RESUMOO congelamento de alimentos se divide em três etapas: resfriamento, congelamento e têmpera. Na etapa de congelamento, ocorre a formação e crescimento de cristais de gelo, de cujo tamanho e distribuição depende a qualidade do produto. O tamanho dos cristais, por sua vez, depende da taxa de congelamento. Assim, quanto maior a taxa de congelamento, menores são os cristais, melhor é sua distribuição e melhor é a qualidade do produto. Visando alcançar essa qualidade, os processos convencionais de congelamento empregam baixas temperaturas do ar, que são mantidas constantes durante toda a operação, acarretando elevado consumo energético. Considerando que as etapas de resfriamento e têmpera não influem diretamente no tamanho dos cristais, foram propostas diferentes estratégias de congelamento, que envolvem a modificação das condições operacionais de temperatura do ar nestas etapas. As estratégias foram comparadas quanto à qualidade do produto e consumo energético do sistema. Para tanto, nabo oriental liofilizado foi produzido, empregando 4 condições operacionais distintas no congelamento das amostras: temperatura do ar constante a -20 °C, constante a -30 °C (processo convencional) e dois processos alternativos modificados (condições de temperatura do ar variáveis por diferentes patamares e condições dinâmicas). Todos os processos foram avaliados, quanto a suas taxas de congelamento, como congelamentos comerciais, sendo que os processos alternativos modificados apresentaram taxa mais próxima ao processo convencional. As amostras liofilizadas foram reidratadas por imersão em água destilada por 5 h. A qualidade das amostras foi avaliada com base em parâmetros de reidratação, referente às diferentes taxas de congelamento. Constatou-se que o processo de congelamento sob condições dinâmicas, resultou no produto de maior qualidade, em termos de reidratação, e que o processo variável por patamares apresentou qualidade similar ao convencional. Por fim, foi desenvolvido um simulador com o qual foram simulados os mesmos processos em condições constantes e modificadas, visando avaliar seu potencial de economia energética. Na simulação, os processos modificados apresentaram economia de energia da ordem de 9 %, com relação ao processo ...

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Reversed Brayton cycle for food freezing at very low temperatures: Energy performance and optimisation

Cited by 21 publications

References 45 publications

Simulation and Evaluation on the Dynamic Performance of a Cryogenic Turbo-Based Reverse Brayton Refrigerator

Simulation and Evaluation on the Dynamic Performance of a Cryogenic Turbo-Based Reverse Brayton Refrigerator

Phase change material‐assisted freezing of tuna: Impact on freezing process and thawing loss

Congelamento de alimentos em condições operacionais alternativas

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