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- Estudo numérico do desempenho térmico de um armário exterior para equipamentos de telecomunicações móveisPublication . Duarte, Miguel Vicente; Silva, Pedro Dinho da; Pires, Luís Carlos Carvalho; Gaspar, Pedro DinisOutdoor cabinets that house telecommunication equipment are used to protect electronic equipment from the harsh environmental conditions. The number of outdoor cabinets used has been growing in recent decades, boosted by the world expansion of mobile telecommunications networks. The disposition of telecommunications equipment inside a cabinet (i.e., the thermal design) became a critical factor due to the miniaturization of electronic components and the increase of packing density. To mitigate this problem, energy-intensive cooling techniques (e.g., air conditioning) began to be used. Studies shown that approximately 25% of the total energy consumed in an outdoor cabinet is used for cooling. It is intended with this work, the thermal study of an outdoor cabinet using a CFD software to characterize its thermal behaviour, according to the influence of the environment temperature, the air flow through the cabinet and the heat dissipated in its interior by the telecommunications equipment. According the results obtained in this study it can be concluded that even for the less favourable case (TA=20.1 °C; Qar=60 m3 h -1 e qdis=480 W), none of the telecommunications equipment inside the cabinet is under risk, since the Tmax,cabinet ≈ 4 0°C is lower than the Tmax,recommended ≈55°C.
- Experimental study and numerical simulation of the interior flow in a telecommunications cabinetPublication . Delgado, Christopher B.; Silva, Pedro Dinho da; Pires, Luís Carlos Carvalho; Gaspar, Pedro DinisThe sector of information and communication technologies, especially telecommunications, has grown in a relentless way, leading to an increase in the number of necessary infrastructure to ensure the geographical coverage of the service, having the outdoor telecommunications cabinets (OTC) been an increasingly preferred choice of this type of infrastructure. These cabinets need cooling systems to maintain interior temperatures between desired values, but an effective cooling depends directly on the air flow inside. This paper includes the experimental results of the internal flow and heat transfer in a model a of real OTC, in order to characterize its thermal behavior. The internal air flow is visualized through experimental methods and compared with numerical predictions. The flow occurs mainly in turbulent regime, possessing greater magnitude on the back area of the OTC, where also exist some recirculation zones that can difficult an effective cooling. The results allow to conclude that forced ventilation is an effective method of OTC cooling, combined with low energy consumption.
- Characterization of the thermal performance of an outdoor telecommunication cabinetPublication . Silva, Pedro Dinho da; Pires, Luís; Patrício, Carlos Miguel Rosado; Gaspar, Pedro DinisThis work describes the analysis of the thermal performance of an outdoor telecommunication cabinet (OTC) using the computational tool DesignBuilder. The simulation results are compared to the experimental data collected in real cabinet under normal operating conditions. The simulation results show that the air temperature predicted by the model is closer to the temperature measured experimentally inside the cabinet particularly when the weather data files of the computational model have a similar behavior to the actual weather data. Numerical studies show that the use of mechanical ventilation is effective in the extraction of heat generated inside the cabinet.
- Caracterização do comportamento térmico de um armário exterior de telecomunicações móveisPublication . Patrício, Carlos Miguel Rosado; Silva, Pedro Dinho da; Pires, Luís Carlos Carvalho; Gaspar, Pedro DinisThe growing use of telecommunication technologies by society has led the industry to develop infrastructure to support this growth. The telecommunications outdoor cabinets are an important element in the telecommunications network, allowing host and protect the equipment needed to run the network in adverse conditions. The enclosure must have a proper thermal performance to ensure a temperature below 55 ° C, limit for the operation of equipment, and avoid an excessive consumption of electricity. This study aims to characterize the thermal performance of the cabinet using numerical studies with DesignBuilder/EnergyPlus. The development of the numerical model is followed by experimental studies using a real cabinet in operation, to ensure that the model is valid and allows to obtain reliable results. Results allowed to elaborate, quantitatively, a thermal characterization of the cabinet and improve the utilization profile.
- Characterization of the thermal performance of outdoor telecommunication cabinetsPublication . Silva, Pedro Dinho da; Pires, Luís Carlos Carvalho; Patrício, Carlos Miguel Rosado; Gaspar, Pedro DinisThe growing use of telecommunication technologies has led the industry to develop infrastructure to support this progress. The outer telecommunications cabinets are part of the Base Transceiver Station allowing to accommodate and protect from outer adverse conditions a set of electronic equipment needed to operate the mobile communication network. This kind of cabinets should have a proper thermal performance to ensure indoor air temperature below 55°C to avoid exceeding the maximum operating temperature of the electronic equipment. This work describes the analysis of the thermal performance of an outdoor telecommunication cabinet using the computational tool DesignBuilder. The simulation results are compared to the experimental data collected in real cabinet under normal operating conditions. The simulation results show that the air temperature predicted by the model is closer to the temperature measured experimentally inside the cabinet particularly when the weather data files of the computational model have a similar behavior to the actual weather data. Numerical studies show that the use of mechanical ventilation is effective in the extraction of heat generated inside the cabinet. However, there is a limit beyond which increasing the air flow rate does not result in a significant decrease of the cabinet air temperature. The studies also show the importance of the radiant properties and the geographical location of the cabinet. High values of the outer surface cabinet emissivity impair the thermal performance of the cabinet during the day and for some locations, an operational mechanical ventilation system may not be enough to maintain the indoor air temperature below 55°C. Overall, the use of DesignBuilder proved to be very effective for characterizing the thermal performance of telecommunications outdoor cabinets.