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- Numerical experimental evaluation of the aerodynamic drag of the air curtain in Vertical Open Refrigerated Display CabinetsPublication . Nascimento, Samuel Mariano do; Heidinger, Gustavo Galdi; Gaspar, Pedro Dinis; Silva, Pedro Dinho daThis paper presents the experimental and numerical results of a set of air curtain evaluations in a Vertical Open Refrigerated Display Cases (VORDC) when subjected to external disturbances due to the transfer of people in front of the air curtain. Previous experimental studies identified that the stability of the air curtain depends on the climatic conditions and ambient air movement inside the stores. The ambient air and VORDC air curtain can be disturbed during the movement of people in front of the VORDC, causing a certain amount of cold air to flow out of the VORDC and consequently hot and humid air entering. It is not possible to quantify exclusively the increase in energy consumption due to the transfer of people in the real case, due to the other variables involved in the process. Thus, a robot (Automated Mannequin for Interference Reproduction in the Air Curtain - MARIA) was mounted on a rail placed around the VORDC, in a climate chamber with controlled environment according to climatic class (n. º 3: T=25°C; =60%). MARIA performed clockwise and counterclockwise movements around the VORDC, with velocities of 0.2 m.s-1 at 0.8 m.s-1, with a pitch of 0.2 m.s-1. For the numerical evaluation, a 3D CFD model was developed to predict and analyze the air flow and heat transfer in the air curtain and outside both ways, refrigerated space and ambient air due to transfer of a body parallel to the air curtain.
- Experimental study of the influence of consumers movement parallel to the frontal opening of a multideck display case on the evaporator's thermal performancePublication . Heidinger, Gustavo Galdi; Nascimento, Samuel Mariano do; Gaspar, Pedro Dinis; Silva, Pedro Dinho daThis paper reports the results of experimental tests performed according to ISO 23953 (climate class n° 3: 25ºC and 60%) in an open refrigerated multideck display case (ORDC) to evaluate the influence of consumers passing in front of its opening on the thermal performance of the evaporator. The consumers’ passage in front of the ORDC is simulated by a robotic mannequin: MARIA - Mannequin for Automatic Replication of the Interference in the Air curtain. Tests are performed for MARIA velocity's ranging from 0.2 ms-1 to 0.8 ms-1, with 0.2 ms-1 velocity steps for two conditions: mannequin moving towards or against the airflow of the test room. All tests are performed in an ORDC with dual air curtain. The results quantify the influence of MARIA translational velocity on the frost formation in the evaporator coil and how this phenomenon affects the evaporator's airflow, inlet and outlet temperatures and sensible and latent heat loads. The analysis of experimental data provides valuable information for evaporator design taking into account usual in-store conditions.
- Comparing open and closed vertical refrigerated display cabinets at mild and tropical external environmentsPublication . Heidinger, Gustavo Galdi; Nascimento, Samuel Mariano do; Gaspar, Pedro Dinis; Silva, Pedro Dinho daThis paper reports the results of experimental tests performed according to ISO 23953 in vertical open and closed refrigerated display cabinets (VORDC vs. VCRDC). Tests were performed at a mild climate class (n. º 3: T=25°C; φ=60%) and a tropical one (n. º 6: T=27°C; φ=70%). The direct energy consumption is 46% higher at VCRDC due to the heated glass doors frame and defrost heaters. The product simulator temperature is higher and more stable at VORDC. The highest product simulator temperature is lower (-1.4°C) at the VCRDC and less stable (+2.7°C variation) due to the opening doors period. The total mass of condensed water at the evaporator is reduced 87% and the total heat load is 77% lower at the VCRDC. Thus, the estimated total energy consumption is reduced 42%. Given the current concerns with energy consumption and sustainability of the heat exchange processes, the VCRDC provide the best solution.
- Inovenergy - Eficiência Energética no setor AgroIndustrial: Manual de Boas PráticasPublication . Andrade, Luís P.; Nunes, José; Silva, Pedro Dinho da; Gaspar, Pedro Dinis; Domingues, Luísa Catarina; Nobre, Telmo; Gaspar, Adélio; Feliciano, Manuel; Araújo, Alberta; Brito, Paulo; Félix, PedroNos últimos 150 anos o clima tem-se tornado progressivamente instável e mais quente. Se nada for feito, estas alterações tendem a acentuar-se e afetarem negativamente o ambiente, com efeitos a nível dos recursos hídricos, das zonas costeiras, da agricultura, da saúde humana, da energia, e da biodiversidade. Estas alterações climáticas estão diretamente relacionadas com o crescimento das emissões dos Gases de Efeito Estufa (GEE), em que se salienta o papel do dióxido de carbono (CO2). Outros gases relevantes para o efeito de estufa incluem o metano (CH4), os óxidos de azoto (NOx) e os compostos fluorados. As emissões de CO2 e de NOx produzidas pelo Homem são maioritariamente atribuídas ao setor energético e aos transportes. A solução para reduzir o excessivo consumo de energia está longe de ser conhecida, contudo devemos procurar fontes de energia alternativas e adotar medidas que promovam essa redução. É neste âmbito que se aplica a eficiência energética. A forma como a energia é utilizada é impreterivelmente uma questão chave neste processo. Como tal, é imprescindível aumentar a eficiência energética nas operações das empresas, de modo a promover a redução de custos, aumentando a competitividade, contribuindo ainda para a redução da intensidade energética global.
- Manual da ferramenta para a otimização da gestão da produção: CárneosPublication . Gândara, J.; Andrade, Luís P.; Pinheiro, R.; Paiva, Teresa; Gaspar, Pedro Dinis; Elias, M.; Pereira, C.D.; Soares, C.; Henriques, M.; Laranjo, Marta; Potes, Maria Eduarda; Santos, Ana Cristina Agulheiro; Santos, Fernando Charrua; Silva, Pedro Dinho da; Nunes, J.; Coutinho, P.; Carneiro, J.; Várzea, J.P.; Velho, Manuela Vaz; Araújo, M.A.; Ribeiro, M.; Santos, J.; Matias, JoãoA aplicação +Agro tem incluída um conjunto de ferramentas que permitem adaptar a informação apresentada de acordo com as suas necessidades. Não são ferramentas de configuração, edição ou eliminação, pelo que sintase confortável em experimentá -las, para averiguar da sua utilidade.
- Estudo de conservação sob atmosfera controlada na qualidade da cereja cv. Satin.Publication . Espírito Santo, Christophe; Belane, Yuran; Resende, Mafalda; Caseiro, Catarina; Beato, Helena; Reis, João; Brandão, Inês; Silveira, Ana; Riscado, Ana; Baptista, Cátia; Pintado, Cristina Miguel; Veloso, Abel; Ferreira, Dora; Andrade, Luís P.; Nunes, José; Simões, Maria Paula; Morais, Diogo Cerqueira; Teixeira, Maria Cristina Canavarro; Gaspar, Pedro Dinis; Silva, Pedro Dinho daA cerejeira (Prunus avium L.) é uma espécie pertencente à subfamília das Prunóideas e a produção de cereja apresenta elevada importância económica na região da Beira Interior, que, embora não seja a região com maior área de produção é a principal região de produção de Portugal. A cereja apresenta um elevado teor de compostos bioativos como vitamina C, fibra, antocianinas, quercetina e carotenóides relacionados com a prevenção de doenças cardiovasculares, diabetes e cancro (McCune et al., 2011; Wang et al., 2016). No entanto, este fruto não climatérico deteriora-se rapidamente após a colheita apresentando alterações na cor da pele, acastanhamento do pedúnculo, desidratação, amolecimento da polpa, diminuição da acidez e apodrecimento (Dugan & Roberts, 1997; Wang et al., 2016). A refrigeração, combinada com a utilização de atmosferas controladas, visa o atraso da deterioração e o consequente prolongamento da vida útil alargando o período de oferta. Esta técnica consiste no armazenamento a baixa temperatura num ambiente com uma concentração elevada de CO2, uma concentração baixa de O2 e uma humidade relativa elevada (Andrade et al., 2019). Os valores indicados na bibliografia relativos à concentração de CO2 variam entre 5% e 20% (Gross et al., 2016) e, para a concentração de O2, encontram-se entre 1% (Gross et al., 2016) e 10% (Ben-Yehoshua et al., 2005)
- Further development and experimental testing of a resistive sensor for monitoring frost formation in refrigeration systemsPublication . Aguiar, Martim; Gaspar, Pedro Dinis; Silva, Pedro Dinho daRefrigeration systems are widely accepted as a mean to prevent food degradation. These systems usually rely on fin-and-tube heat exchangers to lower the air temperature. Due to long operation times and surface temperatures below dew point, frost may form and accumulate on the evaporators fin surface. This frost accumulation reduces and may clog the airflow, decreasing the system efficiency. Usually, most systems use a time-controlled system (stopping the compressor with or without powering a heating resistor inserted among fins to heat) to melt the ice. This method does not measure or predict the amount of frost formed, thus it is not reliable. Ice sensors that are cheap, reliable and easy to implement in commercial systems are studied. A resistive sensor is purposed, that measures the voltage between two electrodes with the water phase change (condensation and solidification -freezing-), as these states have different resistive values. Different electrode materials, morphologies and configurations are studied in order to obtain the best design.
- Performance variation of vertical open refrigerated display cases in-situ operation and testing according to ISO and ASHRAE standardsPublication . Nascimento, Samuel Mariano do; Heidinger, Gustavo Galdi; Gaspar, Pedro Dinis; Silva, Pedro Dinho daRefrigerated display cases are an equipment widely used in sales environments, such as stores and super markets. Most equipment are open type since they provide a good marketing appeal. This type of equipment is used to expose perishable foods or chilled drinks. Manufacturers seek during the design phase of the equipment to certify its suitability to the testing standards with the lowest energy consumption and ensuring food safety. With the aim to assist the development of new equipment that meet the test conditions established by testing standards and market needs, experimental tests were conducted comparing real operation conditions and test conditions following the testing standards ISO 23953/2005 and ASHRAE 72-2005. The experimental results show that test conditions required by standards are stricter than in-situ operation, providing higher conservation temperatures (56% increase) and energy consumption (17% increase). The experimental study considers an open vertical refrigerated display case that demands high electrical energy consumption due to its characteristics. The tests performed in the laboratory using a climatic chamber determine approximately 17% higher thermal load values than those of in-situ operation with remote refrigeration system. This condition arises from the different airflow conditions that are found inside stores when comparing with the conditions and patterns imposed by standards for equipment testing. This difference has a negative impact in the commercial scope since equipment manufacturers relate lower thermal load values than those determined in tests of similar models according to standards.
- Parametric Numerical Study of the Airflow and Thermal Performance in a Real Data Center for Improving SustainabilityPublication . Macedo, Diogo Gonçalves Costa e Silva de; Godina, Radu; Gaspar, Pedro Dinis; Silva, Pedro Dinho da; Covas, Miguel TrigueirosIn recent years, reducing energy consumption has been relentlessly pursued by researchers and policy makers with the purpose of achieving a more sustainable future. The demand for data storage in data centers has been steadily increasing, leading to an increase in size and therefore to consume more energy. Consequently, the reduction of the energy consumption of data center rooms is required and it is with this perspective that this paper is proposed. By using Computational Fluid Dynamics (CFD), it is possible to model a three-dimensional model of the heat transfer and air flow in data centers, which allows forecasting the air speed and temperature range under diverse conditions of operation. In this paper, a CFD study of the thermal performance and airflow in a real data center processing room with 208 racks under di erent thermal loads and airflow velocities is proposed. The physical-mathematical model relies on the equations of mass, momentum and energy conservation. The fluid in this study is air and it is modeled as an ideal gas with constant properties. The model of the e ect of turbulence is made by employing a k–" standard model. The results indicate that it is possible to reduce the thermal load of the server racks by improving the thermal performance and airflow of the data center room, without a ecting the correct operation of the server racks located in the sensible regions of the room.
- Guia de Boas Práticas: Gestão de Processos ProdutivosPublication . Andrade, Luís P.; Nunes, J.; Paiva, Teresa; Gândara, J.; Pinheiro, R.; Gaspar, Pedro Dinis; Elias, M.; Pereira, C. D.; Soares, C.; Henriques, M.; Laranjo, M.; Potes, Maria Eduarda; Santos, A. C. Agulheiro; Santos, Fernando Charrua; Silva, Pedro Dinho da; Coutinho, P.; Carneiro, J.; Várzea, J. P.; Velho, Manuela Vaz; Araújo, M. A.; Ribeiro, M.; Santos, J.; Matias, JoãoO projeto +Agro - Qualificação organizacional, +AGRO energética e de segurança e saúde no trabalho da indústria agroalimentar visa qualificar as Pequenas e Médias Empresas (PME’s) do setor agroalimentar para a adoção de estratégias inovadoras, com recurso às Tecnologias da Informação, Comunicação & Eletrónica (TICE), que lhes permitam aumentar a sua produtividade e eficiência ao nível da prevenção de riscos de Segurança e Saúde no Trabalho (SST), da eficiência energética e da otimização de processos de produção. O projeto incide nomeadamente nos subsetores dos produtos cárneos, dos produtos hortofrutícolas, dos produtos lácteos e dos produtos de padaria, por serem estes nos quais existem maior número de empresas com produtos diferenciados com valorização nos mercados nacional e internacional.